diff --git a/gtk2_ardour/about.cc b/gtk2_ardour/about.cc
index 5ecc075c30..571f602e71 100644
--- a/gtk2_ardour/about.cc
+++ b/gtk2_ardour/about.cc
@@ -28,7 +28,6 @@
 #include "pbd/file_utils.h"
 
 #include "ardour/svn_revision.h"
-#include "ardour/ardour.h"
 #include "ardour/version.h"
 #include "ardour/filesystem_paths.h"
 
diff --git a/gtk2_ardour/actions.cc b/gtk2_ardour/actions.cc
index 0db4831e6f..5391d58f42 100644
--- a/gtk2_ardour/actions.cc
+++ b/gtk2_ardour/actions.cc
@@ -31,7 +31,6 @@
 #include "pbd/error.h"
 #include "pbd/file_utils.h"
 
-#include "ardour/ardour.h"
 #include "ardour/filesystem_paths.h"
 #include "ardour/rc_configuration.h"
 
diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index d54ae5e291..6236bcd5dc 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -60,26 +60,18 @@
 #include "midi++/manager.h"
 
 #include "ardour/ardour.h"
-#include "ardour/callback.h"
+#include "ardour/audioengine.h"
+#include "ardour/audiofilesource.h"
+#include "ardour/diskstream.h"
+#include "ardour/filename_extensions.h"
+#include "ardour/port.h"
+#include "ardour/process_thread.h"
 #include "ardour/profile.h"
-#include "ardour/plugin_manager.h"
+#include "ardour/recent_sessions.h"
 #include "ardour/session_directory.h"
 #include "ardour/session_route.h"
 #include "ardour/session_state_utils.h"
 #include "ardour/session_utils.h"
-#include "ardour/port.h"
-#include "ardour/audioengine.h"
-#include "ardour/playlist.h"
-#include "ardour/utils.h"
-#include "ardour/audio_diskstream.h"
-#include "ardour/audiofilesource.h"
-#include "ardour/recent_sessions.h"
-#include "ardour/port.h"
-#include "ardour/audio_track.h"
-#include "ardour/midi_track.h"
-#include "ardour/filesystem_paths.h"
-#include "ardour/filename_extensions.h"
-#include "ardour/process_thread.h"
 
 typedef uint64_t microseconds_t;
 
@@ -121,6 +113,7 @@ using namespace ARDOUR;
 using namespace PBD;
 using namespace Gtkmm2ext;
 using namespace Gtk;
+using namespace std;
 
 ARDOUR_UI *ARDOUR_UI::theArdourUI = 0;
 UIConfiguration *ARDOUR_UI::ui_config = 0;
@@ -130,7 +123,7 @@ sigc::signal<void>      ARDOUR_UI::RapidScreenUpdate;
 sigc::signal<void>      ARDOUR_UI::SuperRapidScreenUpdate;
 sigc::signal<void, framepos_t, bool, framepos_t> ARDOUR_UI::Clock;
 
-bool could_be_a_valid_path (const string& path);
+bool could_be_a_valid_path (const std::string& path);
 
 ARDOUR_UI::ARDOUR_UI (int *argcp, char **argvp[])
 
@@ -335,7 +328,7 @@ ARDOUR_UI::ARDOUR_UI (int *argcp, char **argvp[])
 
 /** @return true if a session was chosen and `apply' clicked, otherwise false if `cancel' was clicked */
 bool
-ARDOUR_UI::run_startup (bool should_be_new, string load_template)
+ARDOUR_UI::run_startup (bool should_be_new, std::string load_template)
 {
 	delete _startup;
 	_startup = new ArdourStartup ();
diff --git a/gtk2_ardour/ardour_ui2.cc b/gtk2_ardour/ardour_ui2.cc
index 05addb98e3..74353d21c0 100644
--- a/gtk2_ardour/ardour_ui2.cc
+++ b/gtk2_ardour/ardour_ui2.cc
@@ -37,11 +37,9 @@
 #include <gtkmm2ext/click_box.h>
 #include <gtkmm2ext/tearoff.h>
 
-#include "ardour/session.h"
-#include "ardour/audioengine.h"
-#include "ardour/ardour.h"
 #include "ardour/profile.h"
-#include "ardour/route.h"
+#include "ardour/session.h"
+#include "ardour/types.h"
 
 #include "ardour_ui.h"
 #include "keyboard.h"
diff --git a/gtk2_ardour/ardour_ui_ed.cc b/gtk2_ardour/ardour_ui_ed.cc
index 35100e940b..bd99be4ff2 100644
--- a/gtk2_ardour/ardour_ui_ed.cc
+++ b/gtk2_ardour/ardour_ui_ed.cc
@@ -61,7 +61,6 @@
 #include "ardour/session.h"
 #include "ardour/profile.h"
 #include "ardour/audioengine.h"
-#include "ardour/control_protocol_manager.h"
 
 #include "control_protocol/control_protocol.h"
 
diff --git a/gtk2_ardour/ardour_ui_options.cc b/gtk2_ardour/ardour_ui_options.cc
index 6c8319e808..19e7106378 100644
--- a/gtk2_ardour/ardour_ui_options.cc
+++ b/gtk2_ardour/ardour_ui_options.cc
@@ -26,10 +26,8 @@
 
 #include <gtkmm2ext/utils.h>
 
-#include "ardour/configuration.h"
-#include "ardour/session.h"
-#include "ardour/audioengine.h"
 #include "ardour/rc_configuration.h"
+#include "ardour/session.h"
 
 #ifdef HAVE_LIBLO
 #include "ardour/osc.h"
diff --git a/gtk2_ardour/audio_clock.cc b/gtk2_ardour/audio_clock.cc
index 76abb9d6bb..e20dfffcd8 100644
--- a/gtk2_ardour/audio_clock.cc
+++ b/gtk2_ardour/audio_clock.cc
@@ -24,17 +24,16 @@
 #include "pbd/enumwriter.h"
 
 #include <gtkmm/style.h>
+#include <sigc++/bind.h>
 
 #include "gtkmm2ext/cairocell.h"
 #include "gtkmm2ext/utils.h"
 #include "gtkmm2ext/rgb_macros.h"
 
-#include "ardour/ardour.h"
+#include "ardour/types.h"
 #include "ardour/session.h"
 #include "ardour/tempo.h"
 #include "ardour/profile.h"
-#include "ardour/slave.h"
-#include <sigc++/bind.h>
 
 #include "ardour_ui.h"
 #include "audio_clock.h"
diff --git a/gtk2_ardour/audio_region_editor.cc b/gtk2_ardour/audio_region_editor.cc
index e06e50f113..2aeb2dbe60 100644
--- a/gtk2_ardour/audio_region_editor.cc
+++ b/gtk2_ardour/audio_region_editor.cc
@@ -17,17 +17,17 @@
 
 */
 
+#include <cmath>
+
+#include <gtkmm2ext/utils.h>
+
 #include "pbd/memento_command.h"
 #include "pbd/stateful_diff_command.h"
 #include "pbd/pthread_utils.h"
 
-#include "ardour/session.h"
 #include "ardour/audioregion.h"
-#include "ardour/playlist.h"
-#include "ardour/utils.h"
+#include "ardour/session_event.h"
 #include "ardour/dB.h"
-#include <gtkmm2ext/utils.h>
-#include <cmath>
 
 #include "audio_region_editor.h"
 #include "audio_region_view.h"
diff --git a/gtk2_ardour/audio_streamview.cc b/gtk2_ardour/audio_streamview.cc
index be8601170f..22e07c0ec9 100644
--- a/gtk2_ardour/audio_streamview.cc
+++ b/gtk2_ardour/audio_streamview.cc
@@ -26,11 +26,9 @@
 
 #include "pbd/stacktrace.h"
 
-#include "ardour/audioplaylist.h"
 #include "ardour/audioregion.h"
 #include "ardour/audiofilesource.h"
 #include "ardour/audio_track.h"
-#include "ardour/source.h"
 #include "ardour/region_factory.h"
 #include "ardour/profile.h"
 #include "ardour/rc_configuration.h"
diff --git a/gtk2_ardour/audio_time_axis.cc b/gtk2_ardour/audio_time_axis.cc
index a34d6421a2..45204971e6 100644
--- a/gtk2_ardour/audio_time_axis.cc
+++ b/gtk2_ardour/audio_time_axis.cc
@@ -36,19 +36,10 @@
 #include <gtkmm2ext/bindable_button.h>
 #include <gtkmm2ext/utils.h>
 
-#include "ardour/amp.h"
-#include "ardour/audioplaylist.h"
 #include "ardour/event_type_map.h"
-#include "ardour/location.h"
 #include "ardour/pannable.h"
 #include "ardour/panner.h"
 #include "ardour/panner_shell.h"
-#include "ardour/playlist.h"
-#include "ardour/processor.h"
-#include "ardour/profile.h"
-#include "ardour/session.h"
-#include "ardour/session_playlist.h"
-#include "ardour/utils.h"
 
 #include "ardour_button.h"
 #include "ardour_ui.h"
@@ -67,8 +58,6 @@
 #include "audio_streamview.h"
 #include "utils.h"
 
-#include "ardour/audio_track.h"
-
 #include "i18n.h"
 
 using namespace std;
diff --git a/gtk2_ardour/automation_controller.cc b/gtk2_ardour/automation_controller.cc
index d6c3d5b824..bb51b94fc4 100644
--- a/gtk2_ardour/automation_controller.cc
+++ b/gtk2_ardour/automation_controller.cc
@@ -23,12 +23,8 @@
 
 #include "pbd/error.h"
 
-#include "ardour/automation_list.h"
-#include "ardour/automation_control.h"
-#include "ardour/event_type_map.h"
 #include "ardour/automatable.h"
-#include "ardour/panner.h"
-#include "ardour/pan_controllable.h"
+#include "ardour/automation_control.h"
 #include "ardour/session.h"
 
 #include "ardour_ui.h"
diff --git a/gtk2_ardour/automation_region_view.cc b/gtk2_ardour/automation_region_view.cc
index ed1283e024..0fb22b05bc 100644
--- a/gtk2_ardour/automation_region_view.cc
+++ b/gtk2_ardour/automation_region_view.cc
@@ -26,7 +26,6 @@
 #include "ardour/midi_automation_list_binder.h"
 #include "ardour/midi_region.h"
 #include "ardour/session.h"
-#include "ardour/source.h"
 
 #include "automation_region_view.h"
 #include "editing.h"
diff --git a/gtk2_ardour/automation_streamview.cc b/gtk2_ardour/automation_streamview.cc
index ba3426678e..65df722e3c 100644
--- a/gtk2_ardour/automation_streamview.cc
+++ b/gtk2_ardour/automation_streamview.cc
@@ -26,7 +26,6 @@
 
 #include "ardour/midi_region.h"
 #include "ardour/midi_source.h"
-#include "ardour/region_factory.h"
 
 #include "automation_streamview.h"
 #include "region_view.h"
diff --git a/gtk2_ardour/axis_view.cc b/gtk2_ardour/axis_view.cc
index 43763abcc3..7a449843e0 100644
--- a/gtk2_ardour/axis_view.cc
+++ b/gtk2_ardour/axis_view.cc
@@ -32,9 +32,6 @@
 #include <gtkmm2ext/selector.h>
 #include <gtkmm2ext/gtk_ui.h>
 
-#include "ardour/session.h"
-#include "ardour/utils.h"
-
 #include "public_editor.h"
 #include "ardour_ui.h"
 #include "gui_object.h"
diff --git a/gtk2_ardour/bundle_manager.cc b/gtk2_ardour/bundle_manager.cc
index 1c89f7b3cd..9dff8f82d2 100644
--- a/gtk2_ardour/bundle_manager.cc
+++ b/gtk2_ardour/bundle_manager.cc
@@ -27,7 +27,6 @@
 
 #include "ardour/session.h"
 #include "ardour/user_bundle.h"
-#include "ardour/audioengine.h"
 #include "bundle_manager.h"
 #include "gui_thread.h"
 #include "i18n.h"
diff --git a/gtk2_ardour/canvas-flag.h b/gtk2_ardour/canvas-flag.h
index ef78221803..c8b32c72a5 100644
--- a/gtk2_ardour/canvas-flag.h
+++ b/gtk2_ardour/canvas-flag.h
@@ -6,8 +6,6 @@
 #include <libgnomecanvasmm/widget.h>
 #include <libgnomecanvasmm/text.h>
 
-#include "ardour/midi_model.h"
-
 #include "simplerect.h"
 #include "simpleline.h"
 
@@ -20,19 +18,19 @@ class CanvasFlag : public Group
 {
 public:
 	CanvasFlag(MidiRegionView& region,
-                   Group&          parent,
-                   double          height,
-                   guint           outline_color_rgba = 0xc0c0c0ff,
-                   guint           fill_color_rgba = 0x07070707,
-                   double          x = 0.0,
-                   double          y = 0.0);
+	           Group&          parent,
+	           double          height,
+	           guint           outline_color_rgba = 0xc0c0c0ff,
+	           guint           fill_color_rgba = 0x07070707,
+	           double          x = 0.0,
+	           double          y = 0.0);
 
 	virtual ~CanvasFlag();
 
 	virtual bool on_event(GdkEvent* ev);
 
 	virtual void set_text(const std::string& a_text);
-        virtual void set_height (double);
+	virtual void set_height (double);
 
 protected:
 	Text*            _text;
diff --git a/gtk2_ardour/canvas-sysex.h b/gtk2_ardour/canvas-sysex.h
index 281cbb557a..718f81fd6a 100644
--- a/gtk2_ardour/canvas-sysex.h
+++ b/gtk2_ardour/canvas-sysex.h
@@ -20,6 +20,8 @@
 #ifndef CANVAS_SYSEX_H_
 #define CANVAS_SYSEX_H_
 
+#include <string>
+
 #include "canvas-flag.h"
 
 class MidiRegionView;
@@ -33,7 +35,7 @@ public:
 	CanvasSysEx(
 			MidiRegionView& region,
 			Group&          parent,
-			string&         text,
+			std::string&    text,
 			double          height,
 			double          x,
 			double          y);
diff --git a/gtk2_ardour/edit_note_dialog.cc b/gtk2_ardour/edit_note_dialog.cc
index 5f3cb16502..4195ab8962 100644
--- a/gtk2_ardour/edit_note_dialog.cc
+++ b/gtk2_ardour/edit_note_dialog.cc
@@ -19,11 +19,11 @@
 
 #include <gtkmm/stock.h>
 #include <gtkmm/table.h>
-#include "ardour/midi_model.h"
-#include "ardour/midi_region.h"
-#include "edit_note_dialog.h"
+
 #include "canvas-note-event.h"
+#include "edit_note_dialog.h"
 #include "midi_region_view.h"
+
 #include "i18n.h"
 
 using namespace Gtk;
diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index 0ba5f4054c..d19359a0f3 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -60,20 +60,14 @@
 #include "gtkmm2ext/cell_renderer_pixbuf_toggle.h"
 
 #include "ardour/audio_track.h"
-#include "ardour/audioplaylist.h"
+#include "ardour/audioengine.h"
 #include "ardour/audioregion.h"
 #include "ardour/location.h"
-#include "ardour/midi_region.h"
-#include "ardour/plugin_manager.h"
 #include "ardour/profile.h"
 #include "ardour/route_group.h"
-#include "ardour/session_directory.h"
-#include "ardour/session_route.h"
-#include "ardour/session_state_utils.h"
+#include "ardour/session_playlists.h"
 #include "ardour/tempo.h"
 #include "ardour/utils.h"
-#include "ardour/session_playlists.h"
-#include "ardour/audioengine.h"
 
 #include "control_protocol/control_protocol.h"
 
diff --git a/gtk2_ardour/editor_actions.cc b/gtk2_ardour/editor_actions.cc
index e544f7d8c3..074d51428e 100644
--- a/gtk2_ardour/editor_actions.cc
+++ b/gtk2_ardour/editor_actions.cc
@@ -20,17 +20,16 @@
 #include <gio/gio.h>
 #include <gtk/gtkiconfactory.h>
 
-
 #include "pbd/filesystem.h"
 #include "pbd/file_utils.h"
 #include "pbd/search_path.h"
 
 #include "gtkmm2ext/tearoff.h"
 
-#include "ardour/ardour.h"
 #include "ardour/filesystem_paths.h"
 #include "ardour/profile.h"
 #include "ardour/session.h"
+#include "ardour/types.h"
 
 #include "actions.h"
 #include "ardour_ui.h"
diff --git a/gtk2_ardour/editor_audio_import.cc b/gtk2_ardour/editor_audio_import.cc
index 8bd17c92f6..aaf587a464 100644
--- a/gtk2_ardour/editor_audio_import.cc
+++ b/gtk2_ardour/editor_audio_import.cc
@@ -33,22 +33,16 @@
 
 #include <gtkmm2ext/choice.h>
 
-#include "ardour/session.h"
-#include "ardour/session_directory.h"
-#include "ardour/audioplaylist.h"
-#include "ardour/audioregion.h"
-#include "ardour/audio_diskstream.h"
-#include "ardour/midi_track.h"
-#include "ardour/midi_region.h"
-#include "ardour/utils.h"
 #include "ardour/audio_track.h"
-#include "ardour/audioplaylist.h"
 #include "ardour/audiofilesource.h"
-#include "ardour/region_factory.h"
-#include "ardour/source_factory.h"
-#include "ardour/session.h"
-#include "ardour/smf_source.h"
+#include "ardour/audioregion.h"
+#include "ardour/midi_region.h"
+#include "ardour/midi_track.h"
 #include "ardour/operations.h"
+#include "ardour/region_factory.h"
+#include "ardour/smf_source.h"
+#include "ardour/source_factory.h"
+#include "ardour/utils.h"
 #include "pbd/memento_command.h"
 
 #include "ardour_ui.h"
diff --git a/gtk2_ardour/editor_audiotrack.cc b/gtk2_ardour/editor_audiotrack.cc
index 5eadac1ca5..df88f7b65f 100644
--- a/gtk2_ardour/editor_audiotrack.cc
+++ b/gtk2_ardour/editor_audiotrack.cc
@@ -17,8 +17,6 @@
 
 */
 
-#include "ardour/location.h"
-#include "ardour/audio_diskstream.h"
 #include "ardour/rc_configuration.h"
 
 #include "ardour_ui.h"
diff --git a/gtk2_ardour/editor_canvas_events.cc b/gtk2_ardour/editor_canvas_events.cc
index 77bc5ec27b..e6b0b8ec9e 100644
--- a/gtk2_ardour/editor_canvas_events.cc
+++ b/gtk2_ardour/editor_canvas_events.cc
@@ -24,10 +24,8 @@
 
 #include "pbd/stacktrace.h"
 
-#include "ardour/audioplaylist.h"
-#include "ardour/audioregion.h"
-#include "ardour/region_factory.h"
 #include "ardour/midi_region.h"
+#include "ardour/region_factory.h"
 
 #include "editor.h"
 #include "keyboard.h"
diff --git a/gtk2_ardour/editor_export_audio.cc b/gtk2_ardour/editor_export_audio.cc
index dbe95c229f..509e629aee 100644
--- a/gtk2_ardour/editor_export_audio.cc
+++ b/gtk2_ardour/editor_export_audio.cc
@@ -29,10 +29,8 @@
 
 #include "pbd/pthread_utils.h"
 
-#include "ardour/audio_diskstream.h"
 #include "ardour/audio_track.h"
 #include "ardour/audiofilesource.h"
-#include "ardour/audiofilesource.h"
 #include "ardour/audioplaylist.h"
 #include "ardour/audioregion.h"
 #include "ardour/chan_count.h"
diff --git a/gtk2_ardour/editor_keys.cc b/gtk2_ardour/editor_keys.cc
index 2da3122d48..d887697d63 100644
--- a/gtk2_ardour/editor_keys.cc
+++ b/gtk2_ardour/editor_keys.cc
@@ -21,17 +21,17 @@
 #include <cmath>
 #include <string>
 
+#include <gtkmm/treeview.h>
+
 #include "pbd/error.h"
 
 #include "ardour/session.h"
-#include "ardour/region.h"
-#include <gtkmm/treeview.h>
 
 #include "ardour_ui.h"
 #include "editor.h"
-#include "time_axis_view.h"
 #include "region_view.h"
 #include "selection.h"
+#include "time_axis_view.h"
 
 #include "i18n.h"
 
diff --git a/gtk2_ardour/editor_mouse.cc b/gtk2_ardour/editor_mouse.cc
index 7f4445652a..b5c7635265 100644
--- a/gtk2_ardour/editor_mouse.cc
+++ b/gtk2_ardour/editor_mouse.cc
@@ -62,20 +62,14 @@
 #include "editor_cursors.h"
 #include "verbose_cursor.h"
 
-#include "ardour/types.h"
-#include "ardour/profile.h"
-#include "ardour/route.h"
-#include "ardour/audio_track.h"
-#include "ardour/playlist.h"
-#include "ardour/audioplaylist.h"
 #include "ardour/audioregion.h"
-#include "ardour/midi_region.h"
-#include "ardour/dB.h"
-#include "ardour/utils.h"
-#include "ardour/region_factory.h"
-#include "ardour/source_factory.h"
-#include "ardour/session.h"
 #include "ardour/operations.h"
+#include "ardour/playlist.h"
+#include "ardour/profile.h"
+#include "ardour/region_factory.h"
+#include "ardour/route.h"
+#include "ardour/session.h"
+#include "ardour/types.h"
 
 #include <bitset>
 
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index d6cae9a8e2..7f4c22616e 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -49,12 +49,10 @@
 #include "ardour/quantize.h"
 #include "ardour/region_factory.h"
 #include "ardour/reverse.h"
-#include "ardour/route_group.h"
 #include "ardour/session.h"
 #include "ardour/session_playlists.h"
 #include "ardour/strip_silence.h"
 #include "ardour/transient_detector.h"
-#include "ardour/utils.h"
 
 #include "ardour_ui.h"
 #include "debug.h"
diff --git a/gtk2_ardour/editor_regions.cc b/gtk2_ardour/editor_regions.cc
index ab4f7afe3c..01b26705f5 100644
--- a/gtk2_ardour/editor_regions.cc
+++ b/gtk2_ardour/editor_regions.cc
@@ -28,10 +28,9 @@
 
 #include "ardour/audioregion.h"
 #include "ardour/audiofilesource.h"
+#include "ardour/silentfilesource.h"
 #include "ardour/region_factory.h"
 #include "ardour/session.h"
-#include "ardour/session_playlists.h"
-#include "ardour/silentfilesource.h"
 #include "ardour/profile.h"
 
 #include "gtkmm2ext/choice.h"
diff --git a/gtk2_ardour/editor_selection.cc b/gtk2_ardour/editor_selection.cc
index 8e2b668375..6e12a03856 100644
--- a/gtk2_ardour/editor_selection.cc
+++ b/gtk2_ardour/editor_selection.cc
@@ -22,12 +22,11 @@
 
 #include "pbd/stacktrace.h"
 
-#include "ardour/session.h"
-#include "ardour/playlist.h"
-#include "ardour/route_group.h"
-#include "ardour/profile.h"
 #include "ardour/midi_region.h"
-#include "ardour/audioplaylist.h"
+#include "ardour/playlist.h"
+#include "ardour/profile.h"
+#include "ardour/route_group.h"
+#include "ardour/session.h"
 
 #include "control_protocol/control_protocol.h"
 
diff --git a/gtk2_ardour/editor_snapshots.cc b/gtk2_ardour/editor_snapshots.cc
index c47c815984..093e21952f 100644
--- a/gtk2_ardour/editor_snapshots.cc
+++ b/gtk2_ardour/editor_snapshots.cc
@@ -25,7 +25,6 @@
 #include "editor_snapshots.h"
 #include "ardour_ui.h"
 #include "i18n.h"
-#include "editor.h"
 #include "utils.h"
 #include "prompter.h"
 
diff --git a/gtk2_ardour/editor_timefx.cc b/gtk2_ardour/editor_timefx.cc
index 34c974e102..b942f04cca 100644
--- a/gtk2_ardour/editor_timefx.cc
+++ b/gtk2_ardour/editor_timefx.cc
@@ -37,14 +37,12 @@
 #include "region_selection.h"
 #include "time_fx_dialog.h"
 
-#include "ardour/session.h"
-#include "ardour/region.h"
-#include "ardour/audioplaylist.h"
-#include "ardour/audio_track.h"
 #include "ardour/audioregion.h"
-#include "ardour/stretch.h"
 #include "ardour/midi_stretch.h"
 #include "ardour/pitch.h"
+#include "ardour/region.h"
+#include "ardour/session.h"
+#include "ardour/stretch.h"
 
 #ifdef USE_RUBBERBAND
 #include "rubberband/RubberBandStretcher.h"
diff --git a/gtk2_ardour/engine_dialog.cc b/gtk2_ardour/engine_dialog.cc
index 712871fcef..de613f3cf4 100644
--- a/gtk2_ardour/engine_dialog.cc
+++ b/gtk2_ardour/engine_dialog.cc
@@ -39,7 +39,6 @@
 #include <alsa/asoundlib.h>
 #endif
 
-#include "ardour/profile.h"
 #include <jack/jack.h>
 
 #include <gtkmm/stock.h>
diff --git a/gtk2_ardour/export_channel_selector.cc b/gtk2_ardour/export_channel_selector.cc
index b9c2dd5a78..78dd8d20f8 100644
--- a/gtk2_ardour/export_channel_selector.cc
+++ b/gtk2_ardour/export_channel_selector.cc
@@ -24,12 +24,9 @@
 
 #include "pbd/convert.h"
 
-#include "ardour/audio_port.h"
 #include "ardour/audio_track.h"
-#include "ardour/audioengine.h"
 #include "ardour/audioregion.h"
 #include "ardour/export_channel_configuration.h"
-#include "ardour/export_handler.h"
 #include "ardour/io.h"
 #include "ardour/route.h"
 #include "ardour/session.h"
diff --git a/gtk2_ardour/export_channel_selector.h b/gtk2_ardour/export_channel_selector.h
index 511ccd5b78..4cb9902ed0 100644
--- a/gtk2_ardour/export_channel_selector.h
+++ b/gtk2_ardour/export_channel_selector.h
@@ -24,7 +24,6 @@
 #include <list>
 
 #include "ardour/export_profile_manager.h"
-#include "ardour/export_channel.h"
 
 #include <gtkmm.h>
 #include <sigc++/signal.h>
diff --git a/gtk2_ardour/export_filename_selector.cc b/gtk2_ardour/export_filename_selector.cc
index e2d360984c..1b85d6585c 100644
--- a/gtk2_ardour/export_filename_selector.cc
+++ b/gtk2_ardour/export_filename_selector.cc
@@ -22,10 +22,6 @@
 
 #include "export_filename_selector.h"
 
-#include "ardour/export_handler.h"
-#include "ardour/session.h"
-#include "ardour/session_directory.h"
-
 #include "i18n.h"
 
 using namespace ARDOUR;
diff --git a/gtk2_ardour/export_format_selector.cc b/gtk2_ardour/export_format_selector.cc
index 146b31ab51..f66d13d62e 100644
--- a/gtk2_ardour/export_format_selector.cc
+++ b/gtk2_ardour/export_format_selector.cc
@@ -24,7 +24,6 @@
 
 #include "ardour/export_format_specification.h"
 #include "ardour/export_profile_manager.h"
-#include "ardour/session.h"
 
 #include "i18n.h"
 
diff --git a/gtk2_ardour/export_timespan_selector.cc b/gtk2_ardour/export_timespan_selector.cc
index 41257e1248..a96ea69b6d 100644
--- a/gtk2_ardour/export_timespan_selector.cc
+++ b/gtk2_ardour/export_timespan_selector.cc
@@ -22,7 +22,6 @@
 
 #include "ardour_ui.h"
 
-#include "ardour/tempo.h"
 #include "ardour/location.h"
 #include "ardour/types.h"
 #include "ardour/session.h"
diff --git a/gtk2_ardour/export_timespan_selector.h b/gtk2_ardour/export_timespan_selector.h
index 420baa5806..2118a57b83 100644
--- a/gtk2_ardour/export_timespan_selector.h
+++ b/gtk2_ardour/export_timespan_selector.h
@@ -21,7 +21,6 @@
 #ifndef __export_timespan_selector_h__
 #define __export_timespan_selector_h__
 
-#include "public_editor.h"
 #include "audio_clock.h"
 
 #include <list>
@@ -40,6 +39,7 @@ namespace ARDOUR {
 }
 
 using ARDOUR::CDMarkerFormat;
+using ARDOUR::framecnt_t;
 
 /// Timespan Selector base
 class ExportTimespanSelector : public Gtk::VBox, public ARDOUR::SessionHandlePtr
diff --git a/gtk2_ardour/fft_result.h b/gtk2_ardour/fft_result.h
index 2873138dfd..ddf2bb1842 100644
--- a/gtk2_ardour/fft_result.h
+++ b/gtk2_ardour/fft_result.h
@@ -21,7 +21,6 @@
 #ifndef __ardour_fft_result_h
 #define __ardour_fft_result_h
 
-#include "ardour/types.h"
 #include <fftw3.h>
 
 #include <gdkmm/color.h>
diff --git a/gtk2_ardour/gain_meter.cc b/gtk2_ardour/gain_meter.cc
index b571ed52c7..9f4e286f3a 100644
--- a/gtk2_ardour/gain_meter.cc
+++ b/gtk2_ardour/gain_meter.cc
@@ -20,10 +20,7 @@
 #include <limits.h>
 
 #include "ardour/amp.h"
-#include "ardour/io.h"
-#include "ardour/route.h"
 #include "ardour/route_group.h"
-#include "ardour/session.h"
 #include "ardour/session_route.h"
 #include "ardour/dB.h"
 #include "ardour/utils.h"
diff --git a/gtk2_ardour/io_selector.cc b/gtk2_ardour/io_selector.cc
index 19f25dcf1c..db165b8b3c 100644
--- a/gtk2_ardour/io_selector.cc
+++ b/gtk2_ardour/io_selector.cc
@@ -17,21 +17,18 @@
 
 */
 
+#include <stdint.h>
+
 #include <glibmm/objectbase.h>
 
 #include <gtkmm2ext/doi.h>
 
-#include "ardour/port_insert.h"
-#include "ardour/session.h"
-#include "ardour/io.h"
 #include "ardour/audioengine.h"
-#include "ardour/track.h"
-#include "ardour/audio_track.h"
-#include "ardour/midi_track.h"
-#include "ardour/mtdm.h"
-#include "ardour/data_type.h"
-#include "ardour/port.h"
 #include "ardour/bundle.h"
+#include "ardour/data_type.h"
+#include "ardour/io.h"
+#include "ardour/port.h"
+#include "ardour/session.h"
 
 #include "io_selector.h"
 #include "utils.h"
@@ -207,13 +204,13 @@ IOSelector::list_is_global (int dim) const
 	return (dim == _other);
 }
 
-string
+std::string
 IOSelector::disassociation_verb () const
 {
 	return _("Disconnect");
 }
 
-string
+std::string
 IOSelector::channel_noun () const
 {
 	return _("port");
@@ -256,7 +253,7 @@ void
 IOSelectorWindow::on_show ()
 {
 	Gtk::Window::on_show ();
-	pair<uint32_t, uint32_t> const pm_max = _selector.max_size ();
+	std::pair<uint32_t, uint32_t> const pm_max = _selector.max_size ();
 	resize_window_to_proportion_of_monitor (this, pm_max.first, pm_max.second);
 }
 
@@ -264,8 +261,8 @@ void
 IOSelectorWindow::io_name_changed (void*)
 {
 	ENSURE_GUI_THREAD (*this, &IOSelectorWindow::io_name_changed, src)
-
-	string title;
+		
+	std::string title;
 
 	if (!_selector.find_inputs_for_io_outputs()) {
 		title = string_compose(_("%1 input"), _selector.io()->name());
diff --git a/gtk2_ardour/keyeditor.cc b/gtk2_ardour/keyeditor.cc
index 055a9bcae0..dbe374fcbc 100644
--- a/gtk2_ardour/keyeditor.cc
+++ b/gtk2_ardour/keyeditor.cc
@@ -23,8 +23,6 @@
 
 #include <map>
 
-#include "ardour/profile.h"
-
 #include <gtkmm/stock.h>
 #include <gtkmm/label.h>
 #include <gtkmm/accelkey.h>
diff --git a/gtk2_ardour/level_meter.cc b/gtk2_ardour/level_meter.cc
index 7268e8a2f4..9ccff8d9c9 100644
--- a/gtk2_ardour/level_meter.cc
+++ b/gtk2_ardour/level_meter.cc
@@ -19,9 +19,6 @@
 
 #include <limits.h>
 
-#include "ardour/session.h"
-#include "ardour/session_route.h"
-#include "ardour/dB.h"
 #include "ardour/meter.h"
 
 #include <gtkmm2ext/utils.h>
@@ -39,8 +36,6 @@
 #include "keyboard.h"
 #include "public_editor.h"
 
-#include "ardour/session.h"
-
 #include "i18n.h"
 
 using namespace ARDOUR;
diff --git a/gtk2_ardour/location_ui.cc b/gtk2_ardour/location_ui.cc
index 4ef413aef7..ea6a3f544c 100644
--- a/gtk2_ardour/location_ui.cc
+++ b/gtk2_ardour/location_ui.cc
@@ -22,8 +22,6 @@
 
 #include <gtkmm2ext/utils.h>
 
-#include "ardour/utils.h"
-#include "ardour/configuration.h"
 #include "ardour/session.h"
 #include "pbd/memento_command.h"
 
diff --git a/gtk2_ardour/lv2_plugin_ui.cc b/gtk2_ardour/lv2_plugin_ui.cc
index ab3fe1b39d..e2120e112a 100644
--- a/gtk2_ardour/lv2_plugin_ui.cc
+++ b/gtk2_ardour/lv2_plugin_ui.cc
@@ -18,13 +18,10 @@
 */
 
 #include "ardour/lv2_plugin.h"
-#include "ardour/plugin_manager.h"
-#include "ardour/processor.h"
 #include "ardour/session.h"
 #include "pbd/error.h"
 
 #include "ardour_ui.h"
-#include "gui_thread.h"
 #include "lv2_plugin_ui.h"
 
 #include "lv2/lv2plug.in/ns/extensions/ui/ui.h"
diff --git a/gtk2_ardour/midi_region_view.cc b/gtk2_ardour/midi_region_view.cc
index 142b6c6988..299ca8ee50 100644
--- a/gtk2_ardour/midi_region_view.cc
+++ b/gtk2_ardour/midi_region_view.cc
@@ -31,8 +31,6 @@
 #include "pbd/memento_command.h"
 #include "pbd/stateful_diff_command.h"
 
-#include "ardour/playlist.h"
-#include "ardour/tempo.h"
 #include "ardour/midi_region.h"
 #include "ardour/midi_source.h"
 #include "ardour/midi_model.h"
diff --git a/gtk2_ardour/midi_streamview.cc b/gtk2_ardour/midi_streamview.cc
index 2c8c91ebcd..676aa52028 100644
--- a/gtk2_ardour/midi_streamview.cc
+++ b/gtk2_ardour/midi_streamview.cc
@@ -24,14 +24,12 @@
 
 #include <gtkmm2ext/gtk_ui.h>
 
-#include "ardour/midi_diskstream.h"
-#include "ardour/midi_playlist.h"
 #include "ardour/midi_region.h"
 #include "ardour/midi_source.h"
 #include "ardour/midi_track.h"
 #include "ardour/region_factory.h"
-#include "ardour/smf_source.h"
 #include "ardour/session.h"
+#include "ardour/smf_source.h"
 
 #include "ardour_ui.h"
 #include "canvas-simplerect.h"
diff --git a/gtk2_ardour/midi_time_axis.cc b/gtk2_ardour/midi_time_axis.cc
index f38913fe31..4df22c7c96 100644
--- a/gtk2_ardour/midi_time_axis.cc
+++ b/gtk2_ardour/midi_time_axis.cc
@@ -38,22 +38,22 @@
 #include "gtkmm2ext/bindable_button.h"
 #include "gtkmm2ext/utils.h"
 
-#include "ardour/file_source.h"
-#include "ardour/ladspa_plugin.h"
-#include "ardour/location.h"
-#include "ardour/midi_diskstream.h"
+#include "ardour/event_type_map.h"
 #include "ardour/midi_patch_manager.h"
 #include "ardour/midi_playlist.h"
 #include "ardour/midi_region.h"
 #include "ardour/midi_source.h"
+#include "ardour/midi_track.h"
 #include "ardour/operations.h"
 #include "ardour/playlist.h"
-#include "ardour/processor.h"
+#include "ardour/region.h"
 #include "ardour/region_factory.h"
+#include "ardour/route.h"
 #include "ardour/session.h"
-#include "ardour/session_playlist.h"
-#include "ardour/tempo.h"
-#include "ardour/utils.h"
+#include "ardour/session_object.h"
+#include "ardour/source.h"
+#include "ardour/track.h"
+#include "ardour/types.h"
 
 #include "midi++/names.h"
 
diff --git a/gtk2_ardour/missing_plugin_dialog.cc b/gtk2_ardour/missing_plugin_dialog.cc
index d5edd4ca36..ddbca3a5f4 100755
--- a/gtk2_ardour/missing_plugin_dialog.cc
+++ b/gtk2_ardour/missing_plugin_dialog.cc
@@ -17,7 +17,6 @@
 */
 
 #include <gtkmm/label.h>
-#include "ardour/session.h"
 #include "missing_plugin_dialog.h"
 #include "i18n.h"
 
diff --git a/gtk2_ardour/mixer_group_tabs.cc b/gtk2_ardour/mixer_group_tabs.cc
index 6482abebc2..db586eed7e 100644
--- a/gtk2_ardour/mixer_group_tabs.cc
+++ b/gtk2_ardour/mixer_group_tabs.cc
@@ -22,7 +22,6 @@
 #include "gtkmm2ext/utils.h"
 
 #include "ardour/route_group.h"
-#include "ardour/session.h"
 #include "mixer_group_tabs.h"
 #include "mixer_strip.h"
 #include "mixer_ui.h"
diff --git a/gtk2_ardour/mixer_strip.cc b/gtk2_ardour/mixer_strip.cc
index 542ab7b21f..ff3fd54624 100644
--- a/gtk2_ardour/mixer_strip.cc
+++ b/gtk2_ardour/mixer_strip.cc
@@ -34,24 +34,21 @@
 #include <gtkmm2ext/slider_controller.h>
 #include <gtkmm2ext/bindable_button.h>
 
-#include "ardour/ardour.h"
-#include "ardour/amp.h"
-#include "ardour/session.h"
+#include "ardour/audio_track.h"
 #include "ardour/audioengine.h"
 #include "ardour/internal_send.h"
-#include "ardour/route.h"
-#include "ardour/route_group.h"
-#include "ardour/audio_track.h"
 #include "ardour/midi_track.h"
 #include "ardour/pannable.h"
 #include "ardour/panner.h"
 #include "ardour/panner_shell.h"
-#include "ardour/send.h"
-#include "ardour/processor.h"
-#include "ardour/profile.h"
-#include "ardour/ladspa_plugin.h"
-#include "ardour/user_bundle.h"
 #include "ardour/port.h"
+#include "ardour/profile.h"
+#include "ardour/route.h"
+#include "ardour/route_group.h"
+#include "ardour/send.h"
+#include "ardour/session.h"
+#include "ardour/types.h"
+#include "ardour/user_bundle.h"
 
 #include "ardour_ui.h"
 #include "ardour_window.h"
diff --git a/gtk2_ardour/mixer_ui.cc b/gtk2_ardour/mixer_ui.cc
index 3779f0c042..779369aa90 100644
--- a/gtk2_ardour/mixer_ui.cc
+++ b/gtk2_ardour/mixer_ui.cc
@@ -36,11 +36,9 @@
 #include <gtkmm2ext/tearoff.h>
 #include <gtkmm2ext/window_title.h>
 
-#include "ardour/audio_track.h"
 #include "ardour/plugin_manager.h"
 #include "ardour/route_group.h"
 #include "ardour/session.h"
-#include "ardour/session_route.h"
 
 #include "keyboard.h"
 #include "mixer_ui.h"
diff --git a/gtk2_ardour/monitor_section.cc b/gtk2_ardour/monitor_section.cc
index 82519cc85e..359ce0c796 100644
--- a/gtk2_ardour/monitor_section.cc
+++ b/gtk2_ardour/monitor_section.cc
@@ -8,10 +8,8 @@
 #include "gtkmm2ext/actions.h"
 #include "gtkmm2ext/motionfeedback.h"
 
-#include "ardour/dB.h"
 #include "ardour/monitor_processor.h"
 #include "ardour/route.h"
-#include "ardour/utils.h"
 
 #include "ardour_ui.h"
 #include "gui_thread.h"
diff --git a/gtk2_ardour/mono_panner.cc b/gtk2_ardour/mono_panner.cc
index e93dc83894..8ba9c411bd 100644
--- a/gtk2_ardour/mono_panner.cc
+++ b/gtk2_ardour/mono_panner.cc
@@ -32,9 +32,8 @@
 #include "gtkmm2ext/keyboard.h"
 #include "gtkmm2ext/utils.h"
 
-#include "ardour/panner.h"
-#include "ardour/panner.h"
 #include "ardour/pannable.h"
+#include "ardour/panner.h"
 
 #include "ardour_ui.h"
 #include "global_signals.h"
diff --git a/gtk2_ardour/nag.cc b/gtk2_ardour/nag.cc
index 8d9d75538f..110a977716 100644
--- a/gtk2_ardour/nag.cc
+++ b/gtk2_ardour/nag.cc
@@ -7,7 +7,6 @@
 
 #include "pbd/openuri.h"
 
-#include "ardour/ardour.h"
 #include "ardour/filesystem_paths.h"
 
 #include "nag.h"
diff --git a/gtk2_ardour/note_player.cc b/gtk2_ardour/note_player.cc
index c9c9f9de0e..b9f480a6be 100644
--- a/gtk2_ardour/note_player.cc
+++ b/gtk2_ardour/note_player.cc
@@ -20,7 +20,6 @@
 #include <glibmm/main.h>
 
 #include "ardour/midi_track.h"
-#include "ardour/session.h"
 
 #include "note_player.h"
 
diff --git a/gtk2_ardour/panner_ui.cc b/gtk2_ardour/panner_ui.cc
index 51255d3291..14513ca8ad 100644
--- a/gtk2_ardour/panner_ui.cc
+++ b/gtk2_ardour/panner_ui.cc
@@ -18,13 +18,17 @@
 
 #include <limits.h>
 
-#include "ardour/io.h"
-#include "ardour/dB.h"
 #include <gtkmm2ext/utils.h>
 #include <gtkmm2ext/barcontroller.h>
+
 #include "midi++/manager.h"
 #include "pbd/fastlog.h"
 
+#include "ardour/pannable.h"
+#include "ardour/panner.h"
+#include "ardour/panner_shell.h"
+#include "ardour/session.h"
+
 #include "ardour_ui.h"
 #include "panner_ui.h"
 #include "panner2d.h"
@@ -33,12 +37,6 @@
 #include "stereo_panner.h"
 #include "mono_panner.h"
 
-#include "ardour/delivery.h"
-#include "ardour/session.h"
-#include "ardour/panner.h"
-#include "ardour/pannable.h"
-#include "ardour/panner_shell.h"
-#include "ardour/route.h"
 
 #include "i18n.h"
 
diff --git a/gtk2_ardour/playlist_selector.cc b/gtk2_ardour/playlist_selector.cc
index 31710deb71..cda844ee89 100644
--- a/gtk2_ardour/playlist_selector.cc
+++ b/gtk2_ardour/playlist_selector.cc
@@ -20,12 +20,10 @@
 
 #include <gtkmm/button.h>
 
-#include "ardour/session_playlist.h"
-#include "ardour/audio_diskstream.h"
-#include "ardour/playlist.h"
 #include "ardour/audio_track.h"
 #include "ardour/audioplaylist.h"
-#include "ardour/configuration.h"
+#include "ardour/playlist.h"
+#include "ardour/session_playlist.h"
 
 #include <gtkmm2ext/gtk_ui.h>
 
diff --git a/gtk2_ardour/plugin_eq_gui.h b/gtk2_ardour/plugin_eq_gui.h
index 145edb760e..5743152b15 100644
--- a/gtk2_ardour/plugin_eq_gui.h
+++ b/gtk2_ardour/plugin_eq_gui.h
@@ -21,15 +21,20 @@
 #ifndef __ardour_plugin_eq_gui_h
 #define __ardour_plugin_eq_gui_h
 
+#include "pbd/signals.h"
+
 #include "ardour/buffer_set.h"
-#include "ardour/plugin_insert.h"
-#include "ardour/plugin.h"
 
 #include <gtkmm/table.h>
 #include <gtkmm/drawingarea.h>
 #include <gtkmm/combobox.h>
 #include <gtkmm/liststore.h>
 
+namespace ARDOUR {
+	class Plugin;
+	class PluginInsert;
+}
+
 namespace GTKArdour {
         class FFT;
 }
diff --git a/gtk2_ardour/plugin_selector.cc b/gtk2_ardour/plugin_selector.cc
index 1ec07d1bbe..77b8f26ca9 100644
--- a/gtk2_ardour/plugin_selector.cc
+++ b/gtk2_ardour/plugin_selector.cc
@@ -37,8 +37,6 @@
 
 #include "ardour/plugin_manager.h"
 #include "ardour/plugin.h"
-#include "ardour/configuration.h"
-#include "ardour/session.h"
 
 #include "ardour_ui.h"
 #include "plugin_selector.h"
diff --git a/gtk2_ardour/port_group.cc b/gtk2_ardour/port_group.cc
index 863c29f243..36b9ea1187 100644
--- a/gtk2_ardour/port_group.cc
+++ b/gtk2_ardour/port_group.cc
@@ -24,16 +24,13 @@
 #include "midi++/manager.h"
 #include "midi++/mmc.h"
 
-#include "ardour/audio_track.h"
 #include "ardour/audioengine.h"
-#include "ardour/bundle.h"
-#include "ardour/user_bundle.h"
-#include "ardour/io_processor.h"
-#include "ardour/midi_track.h"
-#include "ardour/port.h"
-#include "ardour/session.h"
 #include "ardour/auditioner.h"
+#include "ardour/bundle.h"
 #include "ardour/control_protocol_manager.h"
+#include "ardour/io_processor.h"
+#include "ardour/session.h"
+#include "ardour/user_bundle.h"
 #include "control_protocol/control_protocol.h"
 
 #include "gui_thread.h"
diff --git a/gtk2_ardour/port_insert_ui.cc b/gtk2_ardour/port_insert_ui.cc
index 4e9a3b1c1e..16beb75877 100644
--- a/gtk2_ardour/port_insert_ui.cc
+++ b/gtk2_ardour/port_insert_ui.cc
@@ -22,17 +22,10 @@
 
 #include <gtkmm2ext/doi.h>
 
+#include "ardour/audioengine.h"
+#include "ardour/mtdm.h"
 #include "ardour/port_insert.h"
 #include "ardour/session.h"
-#include "ardour/io.h"
-#include "ardour/audioengine.h"
-#include "ardour/track.h"
-#include "ardour/audio_track.h"
-#include "ardour/midi_track.h"
-#include "ardour/mtdm.h"
-#include "ardour/data_type.h"
-#include "ardour/port.h"
-#include "ardour/bundle.h"
 
 #include "port_insert_ui.h"
 #include "utils.h"
@@ -170,7 +163,7 @@ PortInsertWindow::PortInsertWindow (ARDOUR::Session* sess, boost::shared_ptr<ARD
 {
 
 	set_name ("IOSelectorWindow");
-	string title = _("Port Insert ");
+	std::string title = _("Port Insert ");
 	title += pi->name();
 	set_title (title);
 
diff --git a/gtk2_ardour/port_matrix_column_labels.cc b/gtk2_ardour/port_matrix_column_labels.cc
index 5496c40a49..1f5a21feec 100644
--- a/gtk2_ardour/port_matrix_column_labels.cc
+++ b/gtk2_ardour/port_matrix_column_labels.cc
@@ -20,7 +20,6 @@
 #include <iostream>
 #include "gtkmm2ext/keyboard.h"
 #include "ardour/bundle.h"
-#include "ardour/types.h"
 #include "port_matrix_column_labels.h"
 #include "port_matrix.h"
 #include "port_matrix_body.h"
diff --git a/gtk2_ardour/port_matrix_grid.cc b/gtk2_ardour/port_matrix_grid.cc
index daa25139dc..c8699ece1e 100644
--- a/gtk2_ardour/port_matrix_grid.cc
+++ b/gtk2_ardour/port_matrix_grid.cc
@@ -20,7 +20,6 @@
 #include <iostream>
 #include <cairo/cairo.h>
 #include "ardour/bundle.h"
-#include "ardour/types.h"
 #include "port_matrix_grid.h"
 #include "port_matrix.h"
 #include "port_matrix_body.h"
diff --git a/gtk2_ardour/processor_box.cc b/gtk2_ardour/processor_box.cc
index 1bba2c8af1..d9c21dcc9b 100644
--- a/gtk2_ardour/processor_box.cc
+++ b/gtk2_ardour/processor_box.cc
@@ -40,13 +40,10 @@
 #include <gtkmm2ext/doi.h>
 
 #include "ardour/amp.h"
-#include "ardour/ardour.h"
 #include "ardour/audio_track.h"
 #include "ardour/audioengine.h"
-#include "ardour/internal_send.h"
 #include "ardour/internal_return.h"
-#include "ardour/ladspa_plugin.h"
-#include "ardour/meter.h"
+#include "ardour/internal_send.h"
 #include "ardour/plugin_insert.h"
 #include "ardour/port_insert.h"
 #include "ardour/profile.h"
@@ -54,7 +51,7 @@
 #include "ardour/route.h"
 #include "ardour/send.h"
 #include "ardour/session.h"
-#include "ardour/dB.h"
+#include "ardour/types.h"
 
 #include "actions.h"
 #include "ardour_dialog.h"
diff --git a/gtk2_ardour/public_editor.cc b/gtk2_ardour/public_editor.cc
index 1b8b5c4801..dc468e4a83 100644
--- a/gtk2_ardour/public_editor.cc
+++ b/gtk2_ardour/public_editor.cc
@@ -18,7 +18,6 @@
 */
 
 #include "public_editor.h"
-#include "editor.h"
 
 PublicEditor* PublicEditor::_instance = 0;
 
diff --git a/gtk2_ardour/public_editor.h b/gtk2_ardour/public_editor.h
index 57e3c8dede..9f903b547c 100644
--- a/gtk2_ardour/public_editor.h
+++ b/gtk2_ardour/public_editor.h
@@ -36,7 +36,6 @@
 #include <sigc++/signal.h>
 
 #include "evoral/types.hpp"
-#include "ardour/route_group.h"
 
 #include "pbd/statefuldestructible.h"
 
diff --git a/gtk2_ardour/region_editor.cc b/gtk2_ardour/region_editor.cc
index 622223047a..cf1bfcfb62 100755
--- a/gtk2_ardour/region_editor.cc
+++ b/gtk2_ardour/region_editor.cc
@@ -17,18 +17,16 @@
 
 */
 
+#include <cmath>
+
+#include <gtkmm/listviewtext.h>
+
 #include "pbd/memento_command.h"
 #include "pbd/stateful_diff_command.h"
 
-#include "ardour/session.h"
 #include "ardour/region.h"
-#include "ardour/playlist.h"
-#include "ardour/utils.h"
-#include "ardour/dB.h"
+#include "ardour/session.h"
 #include "ardour/source.h"
-#include "gtkmm2ext/utils.h"
-#include <gtkmm/listviewtext.h>
-#include <cmath>
 
 #include "ardour_ui.h"
 #include "clock_group.h"
diff --git a/gtk2_ardour/region_view.cc b/gtk2_ardour/region_view.cc
index 1c9b8fe67b..5c6a452b61 100644
--- a/gtk2_ardour/region_view.cc
+++ b/gtk2_ardour/region_view.cc
@@ -26,8 +26,6 @@
 #include <gtkmm2ext/gtk_ui.h>
 
 #include "ardour/playlist.h"
-#include "ardour/audioregion.h"
-#include "ardour/audiosource.h"
 #include "ardour/session.h"
 
 #include "ardour_ui.h"
diff --git a/gtk2_ardour/return_ui.cc b/gtk2_ardour/return_ui.cc
index eabb164785..8120534b7d 100644
--- a/gtk2_ardour/return_ui.cc
+++ b/gtk2_ardour/return_ui.cc
@@ -19,10 +19,9 @@
 
 #include <gtkmm2ext/doi.h>
 
-#include "ardour/amp.h"
 #include "ardour/io.h"
-#include "ardour/return.h"
 #include "ardour/rc_configuration.h"
+#include "ardour/return.h"
 
 #include "utils.h"
 #include "return_ui.h"
diff --git a/gtk2_ardour/rhythm_ferret.cc b/gtk2_ardour/rhythm_ferret.cc
index bd9dd42f87..9400d2fc20 100644
--- a/gtk2_ardour/rhythm_ferret.cc
+++ b/gtk2_ardour/rhythm_ferret.cc
@@ -4,13 +4,10 @@
 #include "pbd/memento_command.h"
 #include "pbd/convert.h"
 
-#include "ardour/transient_detector.h"
-#include "ardour/onset_detector.h"
-#include "ardour/audiosource.h"
 #include "ardour/audioregion.h"
-#include "ardour/playlist.h"
-#include "ardour/region_factory.h"
+#include "ardour/onset_detector.h"
 #include "ardour/session.h"
+#include "ardour/transient_detector.h"
 
 #include "rhythm_ferret.h"
 #include "audio_region_view.h"
diff --git a/gtk2_ardour/route_params_ui.cc b/gtk2_ardour/route_params_ui.cc
index e10fcb4139..ca673954d4 100644
--- a/gtk2_ardour/route_params_ui.cc
+++ b/gtk2_ardour/route_params_ui.cc
@@ -24,9 +24,7 @@
 #include <gtkmm2ext/utils.h>
 #include <gtkmm2ext/window_title.h>
 
-#include "ardour/ardour.h"
 #include "ardour/audioengine.h"
-#include "ardour/audio_track.h"
 #include "ardour/plugin.h"
 #include "ardour/plugin_insert.h"
 #include "ardour/plugin_manager.h"
@@ -34,9 +32,6 @@
 #include "ardour/return.h"
 #include "ardour/route.h"
 #include "ardour/send.h"
-#include "ardour/session.h"
-#include "ardour/session.h"
-#include "ardour/session_route.h"
 
 #include "ardour_ui.h"
 #include "gui_thread.h"
diff --git a/gtk2_ardour/route_processor_selection.cc b/gtk2_ardour/route_processor_selection.cc
index 1810ba674b..e66eaf959e 100644
--- a/gtk2_ardour/route_processor_selection.cc
+++ b/gtk2_ardour/route_processor_selection.cc
@@ -21,10 +21,6 @@
 #include <sigc++/bind.h>
 #include "pbd/error.h"
 
-#include "ardour/playlist.h"
-#include "ardour/processor.h"
-#include "ardour/route.h"
-
 #include "gui_thread.h"
 #include "mixer_strip.h"
 #include "route_processor_selection.h"
diff --git a/gtk2_ardour/route_time_axis.cc b/gtk2_ardour/route_time_axis.cc
index 8fc9b90140..6b52e64572 100644
--- a/gtk2_ardour/route_time_axis.cc
+++ b/gtk2_ardour/route_time_axis.cc
@@ -43,22 +43,12 @@
 #include <gtkmm2ext/utils.h>
 
 #include "ardour/amp.h"
-#include "ardour/audioplaylist.h"
-#include "ardour/diskstream.h"
 #include "ardour/event_type_map.h"
-#include "ardour/ladspa_plugin.h"
-#include "ardour/location.h"
-#include "ardour/panner.h"
-#include "ardour/playlist.h"
-#include "ardour/playlist.h"
 #include "ardour/processor.h"
 #include "ardour/profile.h"
-#include "ardour/region_factory.h"
 #include "ardour/route_group.h"
 #include "ardour/session.h"
-#include "ardour/session_playlist.h"
-#include "ardour/debug.h"
-#include "ardour/utils.h"
+#include "ardour/session_playlists.h"
 #include "evoral/Parameter.hpp"
 
 #include "ardour_ui.h"
diff --git a/gtk2_ardour/route_ui.cc b/gtk2_ardour/route_ui.cc
index 6fdd10d9cc..ff970bc5a1 100644
--- a/gtk2_ardour/route_ui.cc
+++ b/gtk2_ardour/route_ui.cc
@@ -46,16 +46,13 @@
 #include "route_time_axis.h"
 #include "group_tabs.h"
 
-#include "ardour/route.h"
-#include "ardour/event_type_map.h"
-#include "ardour/session.h"
-#include "ardour/audioengine.h"
 #include "ardour/audio_track.h"
-#include "ardour/midi_track.h"
-#include "ardour/template_utils.h"
+#include "ardour/audioengine.h"
 #include "ardour/filename_extensions.h"
-#include "ardour/directory_names.h"
-#include "ardour/profile.h"
+#include "ardour/midi_track.h"
+#include "ardour/route.h"
+#include "ardour/session.h"
+#include "ardour/template_utils.h"
 
 #include "i18n.h"
 using namespace Gtk;
diff --git a/gtk2_ardour/send_ui.cc b/gtk2_ardour/send_ui.cc
index e1e3a8b7da..e9699f2cfe 100644
--- a/gtk2_ardour/send_ui.cc
+++ b/gtk2_ardour/send_ui.cc
@@ -19,7 +19,6 @@
 
 #include <gtkmm2ext/doi.h>
 
-#include "ardour/amp.h"
 #include "ardour/io.h"
 #include "ardour/send.h"
 #include "ardour/rc_configuration.h"
diff --git a/gtk2_ardour/session_import_dialog.h b/gtk2_ardour/session_import_dialog.h
index f4ba9cadf7..b31751115f 100644
--- a/gtk2_ardour/session_import_dialog.h
+++ b/gtk2_ardour/session_import_dialog.h
@@ -29,12 +29,11 @@
 #include <gtkmm.h>
 
 #include "pbd/xml++.h"
-#include "ardour/element_importer.h"
-#include "ardour/element_import_handler.h"
 
 #include "ardour_dialog.h"
-
 namespace ARDOUR {
+	class ElementImportHandler;
+	class ElementImporter;
 	class Session;
 }
 
diff --git a/gtk2_ardour/session_metadata_dialog.cc b/gtk2_ardour/session_metadata_dialog.cc
index 5bac706106..1184a89cf5 100644
--- a/gtk2_ardour/session_metadata_dialog.cc
+++ b/gtk2_ardour/session_metadata_dialog.cc
@@ -24,10 +24,9 @@
 #include <gtkmm2ext/utils.h>
 
 #include "pbd/xml++.h"
+
 #include "ardour/session.h"
-#include "ardour/session_directory.h"
 #include "ardour/session_utils.h"
-#include "ardour/configuration.h"
 
 #include "i18n.h"
 
diff --git a/gtk2_ardour/session_option_editor.cc b/gtk2_ardour/session_option_editor.cc
index b9f54f94e8..0f7483a8eb 100644
--- a/gtk2_ardour/session_option_editor.cc
+++ b/gtk2_ardour/session_option_editor.cc
@@ -18,10 +18,6 @@
 */
 
 #include "ardour/session.h"
-#include "ardour/io.h"
-#include "ardour/auditioner.h"
-#include "ardour/audioengine.h"
-#include "ardour/port.h"
 
 #include "gui_thread.h"
 #include "session_option_editor.h"
diff --git a/gtk2_ardour/sfdb_ui.cc b/gtk2_ardour/sfdb_ui.cc
index 5451fe180e..0e233e83d2 100644
--- a/gtk2_ardour/sfdb_ui.cc
+++ b/gtk2_ardour/sfdb_ui.cc
@@ -43,7 +43,6 @@
 
 #include "evoral/SMF.hpp"
 
-#include "ardour/amp.h"
 #include "ardour/audio_library.h"
 #include "ardour/auditioner.h"
 #include "ardour/audioregion.h"
@@ -53,7 +52,6 @@
 #include "ardour/source_factory.h"
 #include "ardour/session.h"
 #include "ardour/session_directory.h"
-#include "ardour/profile.h"
 
 #include "ardour_ui.h"
 #include "editing.h"
diff --git a/gtk2_ardour/streamview.cc b/gtk2_ardour/streamview.cc
index 5dd58deb26..f72b464d80 100644
--- a/gtk2_ardour/streamview.cc
+++ b/gtk2_ardour/streamview.cc
@@ -25,7 +25,6 @@
 
 #include "ardour/playlist.h"
 #include "ardour/region.h"
-#include "ardour/source.h"
 #include "ardour/track.h"
 #include "ardour/session.h"
 
diff --git a/gtk2_ardour/strip_silence_dialog.cc b/gtk2_ardour/strip_silence_dialog.cc
index 0049371a17..32e7bc6054 100644
--- a/gtk2_ardour/strip_silence_dialog.cc
+++ b/gtk2_ardour/strip_silence_dialog.cc
@@ -22,12 +22,10 @@
 #include <gtkmm/table.h>
 #include <gtkmm/label.h>
 #include <gtkmm/stock.h>
-#include "ardour/audioregion.h"
-#include "ardour/audiosource.h"
 
+#include "ardour/audioregion.h"
 #include "ardour/dB.h"
 #include "ardour_ui.h"
-#include "ardour/session.h"
 
 #include "audio_clock.h"
 #include "gui_thread.h"
diff --git a/gtk2_ardour/tape_region_view.cc b/gtk2_ardour/tape_region_view.cc
index 5fef5e46ee..33731798d7 100644
--- a/gtk2_ardour/tape_region_view.cc
+++ b/gtk2_ardour/tape_region_view.cc
@@ -24,7 +24,6 @@
 
 #include <gtkmm2ext/gtk_ui.h>
 
-#include "ardour/playlist.h"
 #include "ardour/audioregion.h"
 #include "ardour/audiosource.h"
 
diff --git a/gtk2_ardour/theme_manager.cc b/gtk2_ardour/theme_manager.cc
index 8c9d559441..71300ad07d 100644
--- a/gtk2_ardour/theme_manager.cc
+++ b/gtk2_ardour/theme_manager.cc
@@ -32,9 +32,7 @@
 
 #include "pbd/file_utils.h"
 
-#include "ardour/configuration.h"
 #include "ardour/filesystem_paths.h"
-#include "ardour/profile.h"
 
 #include "ardour_button.h"
 #include "theme_manager.h"
diff --git a/gtk2_ardour/time_axis_view.cc b/gtk2_ardour/time_axis_view.cc
index 8c30772f0c..229a7065a2 100644
--- a/gtk2_ardour/time_axis_view.cc
+++ b/gtk2_ardour/time_axis_view.cc
@@ -33,12 +33,6 @@
 #include <gtkmm2ext/utils.h>
 #include <gtkmm2ext/selector.h>
 
-#include "ardour/session.h"
-#include "ardour/utils.h"
-#include "ardour/ladspa_plugin.h"
-#include "ardour/processor.h"
-#include "ardour/location.h"
-
 #include "ardour_ui.h"
 #include "global_signals.h"
 #include "gui_thread.h"
diff --git a/gtk2_ardour/time_fx_dialog.cc b/gtk2_ardour/time_fx_dialog.cc
index 0958c20f2e..1fd52cebc3 100644
--- a/gtk2_ardour/time_fx_dialog.cc
+++ b/gtk2_ardour/time_fx_dialog.cc
@@ -36,15 +36,6 @@
 #include "audio_region_view.h"
 #include "region_selection.h"
 
-#include "ardour/session.h"
-#include "ardour/region.h"
-#include "ardour/audioplaylist.h"
-#include "ardour/audio_track.h"
-#include "ardour/audioregion.h"
-#include "ardour/stretch.h"
-#include "ardour/midi_stretch.h"
-#include "ardour/pitch.h"
-
 #ifdef USE_RUBBERBAND
 #include "rubberband/RubberBandStretcher.h"
 using namespace RubberBand;
diff --git a/gtk2_ardour/time_fx_dialog.h b/gtk2_ardour/time_fx_dialog.h
index d47ba4265f..424bfe9813 100644
--- a/gtk2_ardour/time_fx_dialog.h
+++ b/gtk2_ardour/time_fx_dialog.h
@@ -22,11 +22,9 @@
 
 #include <gtkmm.h>
 
-#include "ardour/playlist.h"
 #include "ardour/timefx_request.h"
 
 #include "ardour_dialog.h"
-#include "region_selection.h"
 #include "progress_reporter.h"
 
 class Editor;
diff --git a/gtk2_ardour/time_selection.cc b/gtk2_ardour/time_selection.cc
index 4bc0e2a96a..419d82dbcc 100644
--- a/gtk2_ardour/time_selection.cc
+++ b/gtk2_ardour/time_selection.cc
@@ -20,7 +20,7 @@
 #include <algorithm>
 
 #include "pbd/error.h"
-#include "ardour/ardour.h"
+#include "ardour/types.h"
 
 #include "time_selection.h"
 
diff --git a/gtk2_ardour/ui_config.cc b/gtk2_ardour/ui_config.cc
index 0d41ade0a5..b17316e2db 100644
--- a/gtk2_ardour/ui_config.cc
+++ b/gtk2_ardour/ui_config.cc
@@ -31,7 +31,6 @@
 
 #include "gtkmm2ext/rgb_macros.h"
 
-#include "ardour/ardour.h"
 #include "ardour/filesystem_paths.h"
 
 #include "ui_config.h"
diff --git a/gtk2_ardour/utils.cc b/gtk2_ardour/utils.cc
index 988bd370ae..96bee1a87b 100644
--- a/gtk2_ardour/utils.cc
+++ b/gtk2_ardour/utils.cc
@@ -40,7 +40,6 @@
 #include "pbd/file_utils.h"
 
 #include <gtkmm2ext/utils.h>
-#include "ardour/configuration.h"
 #include "ardour/rc_configuration.h"
 
 #include "ardour/filesystem_paths.h"
diff --git a/libs/ardour/amp.cc b/libs/ardour/amp.cc
index 24b2066ed5..1579b5dcea 100644
--- a/libs/ardour/amp.cc
+++ b/libs/ardour/amp.cc
@@ -26,8 +26,6 @@
 #include "ardour/amp.h"
 #include "ardour/audio_buffer.h"
 #include "ardour/buffer_set.h"
-#include "ardour/configuration.h"
-#include "ardour/io.h"
 #include "ardour/midi_buffer.h"
 #include "ardour/session.h"
 
diff --git a/libs/ardour/analyser.cc b/libs/ardour/analyser.cc
index c19657baaf..730ea4169a 100644
--- a/libs/ardour/analyser.cc
+++ b/libs/ardour/analyser.cc
@@ -22,9 +22,6 @@
 #include "ardour/session_event.h"
 #include "ardour/transient_detector.h"
 
-#include "pbd/pthread_utils.h"
-#include "pbd/convert.h"
-
 using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
diff --git a/libs/ardour/ardour/audio_buffer.h b/libs/ardour/ardour/audio_buffer.h
index 57c5de6124..faa3de7685 100644
--- a/libs/ardour/ardour/audio_buffer.h
+++ b/libs/ardour/ardour/audio_buffer.h
@@ -20,7 +20,9 @@
 #define __ardour_audio_buffer_h__
 
 #include <cstring>
+
 #include "ardour/buffer.h"
+#include "ardour/runtime_functions.h"
 
 namespace ARDOUR {
 
diff --git a/libs/ardour/ardour/audio_playlist_importer.h b/libs/ardour/ardour/audio_playlist_importer.h
index 9b3abfc33d..011bfe39b8 100644
--- a/libs/ardour/ardour/audio_playlist_importer.h
+++ b/libs/ardour/ardour/audio_playlist_importer.h
@@ -30,13 +30,13 @@
 
 #include "ardour/element_importer.h"
 #include "ardour/element_import_handler.h"
-#include "ardour/types.h"
 
 namespace ARDOUR {
 
 class AudioRegionImportHandler;
 class AudioRegionImporter;
 class AudioPlaylistImporter;
+class Session;
 
 class AudioPlaylistImportHandler : public ElementImportHandler
 {
diff --git a/libs/ardour/ardour/audio_region_importer.h b/libs/ardour/ardour/audio_region_importer.h
index 2187d92148..5aee017c51 100644
--- a/libs/ardour/ardour/audio_region_importer.h
+++ b/libs/ardour/ardour/audio_region_importer.h
@@ -30,7 +30,6 @@
 #include "pbd/xml++.h"
 #include "pbd/id.h"
 #include "pbd/filesystem.h"
-#include "ardour/types.h"
 #include "ardour/element_importer.h"
 #include "ardour/element_import_handler.h"
 #include "ardour/import_status.h"
@@ -38,6 +37,8 @@
 namespace ARDOUR {
 
 class Region;
+class Session;
+class Source;
 
 class AudioRegionImportHandler : public ElementImportHandler
 {
diff --git a/libs/ardour/ardour/broadcast_info.h b/libs/ardour/ardour/broadcast_info.h
index 991a3bbbcc..0e87d6e6df 100644
--- a/libs/ardour/ardour/broadcast_info.h
+++ b/libs/ardour/ardour/broadcast_info.h
@@ -22,12 +22,8 @@
 #define __ardour_broadcast_info_h__
 
 #include <string>
-#include <ctime>
-
-#include <sndfile.h>
 
 #include "audiographer/broadcast_info.h"
-#include "ardour/types.h"
 
 namespace ARDOUR
 {
diff --git a/libs/ardour/ardour/buffer.h b/libs/ardour/ardour/buffer.h
index c6f6822519..cbb92e7c4a 100644
--- a/libs/ardour/ardour/buffer.h
+++ b/libs/ardour/ardour/buffer.h
@@ -19,15 +19,12 @@
 #ifndef __ardour_buffer_h__
 #define __ardour_buffer_h__
 
-#include <cstdlib>
-#include <cassert>
-#include <cstring>
-#include <iostream>
+#include <stddef.h>
+
 #include <boost/utility.hpp>
 
 #include "ardour/types.h"
 #include "ardour/data_type.h"
-#include "ardour/runtime_functions.h"
 
 namespace ARDOUR {
 
diff --git a/libs/ardour/ardour/directory_names.h b/libs/ardour/ardour/directory_names.h
index a4235dd9c0..a377d351f6 100644
--- a/libs/ardour/ardour/directory_names.h
+++ b/libs/ardour/ardour/directory_names.h
@@ -2,9 +2,6 @@
 #ifndef __ardour_directory_names_h__
 #define __ardour_directory_names_h__
 
-#include <string>
-#include <stdint.h>
-
 namespace ARDOUR {
 
 extern const char* const old_sound_dir_name;
diff --git a/libs/ardour/ardour/export_channel_configuration.h b/libs/ardour/ardour/export_channel_configuration.h
index a950cecc65..b625be9dc3 100644
--- a/libs/ardour/ardour/export_channel_configuration.h
+++ b/libs/ardour/ardour/export_channel_configuration.h
@@ -28,21 +28,13 @@
 #include <boost/enable_shared_from_this.hpp>
 
 #include "ardour/export_channel.h"
-#include "ardour/export_status.h"
-#include "ardour/ardour.h"
+#include "ardour/export_pointers.h"
 
 #include "pbd/xml++.h"
 
 namespace ARDOUR
 {
 
-class ExportHandler;
-class AudioPort;
-class ExportChannel;
-class ExportFormatSpecification;
-class ExportFilename;
-class ExportProcessor;
-class ExportTimespan;
 class Session;
 
 class ExportChannelConfiguration : public boost::enable_shared_from_this<ExportChannelConfiguration>
diff --git a/libs/ardour/ardour/export_format_base.h b/libs/ardour/ardour/export_format_base.h
index 0ba5f73e8d..46b44e2252 100644
--- a/libs/ardour/ardour/export_format_base.h
+++ b/libs/ardour/ardour/export_format_base.h
@@ -22,22 +22,21 @@
 #define __ardour_export_format_base_h__
 
 #include <set>
-#include <algorithm>
-#include <boost/shared_ptr.hpp>
 #include <string>
 
+#include <boost/shared_ptr.hpp>
+
 #include <sndfile.h>
 #include <samplerate.h>
 
-#include "ardour/ardour.h"
+#include "pbd/signals.h"
+#include "ardour/types.h"
 
 #include "audiographer/general/sample_format_converter.h"
 
 namespace ARDOUR
 {
 
-class HasSampleFormat;
-
 class ExportFormatBase {
   public:
 
diff --git a/libs/ardour/ardour/export_graph_builder.h b/libs/ardour/ardour/export_graph_builder.h
index 18aa8db519..f565fd4134 100644
--- a/libs/ardour/ardour/export_graph_builder.h
+++ b/libs/ardour/ardour/export_graph_builder.h
@@ -21,10 +21,7 @@
 #ifndef __ardour_export_graph_builder_h__
 #define __ardour_export_graph_builder_h__
 
-#include "ardour/ardour.h"
 #include "ardour/export_handler.h"
-#include "ardour/export_channel.h"
-#include "ardour/export_format_base.h"
 
 #include "audiographer/utils/identity_vertex.h"
 
@@ -47,6 +44,9 @@ namespace AudioGrapher {
 namespace ARDOUR
 {
 
+class ExportTimespan;
+class Session;
+
 class ExportGraphBuilder
 {
   private:
diff --git a/libs/ardour/ardour/export_handler.h b/libs/ardour/ardour/export_handler.h
index c4061684eb..eb8ffc2333 100644
--- a/libs/ardour/ardour/export_handler.h
+++ b/libs/ardour/ardour/export_handler.h
@@ -22,13 +22,11 @@
 #define __ardour_export_handler_h__
 
 #include <map>
-#include <list>
 #include <fstream>
 
 #include <boost/operators.hpp>
 #include <boost/shared_ptr.hpp>
 
-#include "ardour/ardour.h"
 #include "ardour/export_pointers.h"
 #include "ardour/session.h"
 #include "ardour/types.h"
@@ -45,7 +43,7 @@ class ExportChannelConfiguration;
 class ExportFormatSpecification;
 class ExportFilename;
 class ExportGraphBuilder;
-
+class Location;
 
 class ExportElementFactory
 {
diff --git a/libs/ardour/ardour/export_status.h b/libs/ardour/ardour/export_status.h
index 164b348c37..cb24cb55f5 100644
--- a/libs/ardour/ardour/export_status.h
+++ b/libs/ardour/ardour/export_status.h
@@ -21,7 +21,6 @@
 #ifndef __ardour_export_status_h__
 #define __ardour_export_status_h__
 
-#include <list>
 #include <stdint.h>
 
 #include "ardour/types.h"
diff --git a/libs/ardour/ardour/export_timespan.h b/libs/ardour/ardour/export_timespan.h
index 9273aab6c7..5cb32dbb1a 100644
--- a/libs/ardour/ardour/export_timespan.h
+++ b/libs/ardour/ardour/export_timespan.h
@@ -21,17 +21,16 @@
 #ifndef __ardour_export_timespan_h__
 #define __ardour_export_timespan_h__
 
-#include <map>
-#include <list>
 #include <string>
 
-#include "ardour/export_status.h"
-#include "ardour/export_channel.h"
-#include "ardour/ardour.h"
+#include <boost/shared_ptr.hpp>
+
+#include "ardour/types.h"
 
 namespace ARDOUR
 {
 
+class ExportStatus;
 class ExportChannel;
 class ExportTempFile;
 
diff --git a/libs/ardour/ardour/location_importer.h b/libs/ardour/ardour/location_importer.h
index 2b6f1ec1c2..332c5ae685 100644
--- a/libs/ardour/ardour/location_importer.h
+++ b/libs/ardour/ardour/location_importer.h
@@ -27,11 +27,12 @@
 #include <boost/shared_ptr.hpp>
 
 #include "pbd/xml++.h"
-#include "ardour/location.h"
-#include "ardour/types.h"
 
 namespace ARDOUR {
 
+class Location;
+class Session;
+
 class LocationImportHandler : public ElementImportHandler
 {
   public:
diff --git a/libs/ardour/ardour/meter.h b/libs/ardour/ardour/meter.h
index 4a9f8305ad..773b04f386 100644
--- a/libs/ardour/ardour/meter.h
+++ b/libs/ardour/ardour/meter.h
@@ -22,7 +22,6 @@
 #include <vector>
 #include "ardour/types.h"
 #include "ardour/processor.h"
-#include "pbd/signals.h"
 #include "pbd/fastlog.h"
 
 namespace ARDOUR {
diff --git a/libs/ardour/ardour/mtdm.h b/libs/ardour/ardour/mtdm.h
index 4948d844f4..9d67e1cd64 100644
--- a/libs/ardour/ardour/mtdm.h
+++ b/libs/ardour/ardour/mtdm.h
@@ -19,10 +19,7 @@
 #ifndef __libardour_mtdm_h__
 #define __libardour_mtdm_h__
 
-#include <cstdlib>
-#include <cstdio>
-#include <cmath>
-#include <unistd.h>
+#include <stddef.h>
 
 class MTDM {
 public:
diff --git a/libs/ardour/ardour/region_factory.h b/libs/ardour/ardour/region_factory.h
index 20ca0d355d..80584e6859 100644
--- a/libs/ardour/ardour/region_factory.h
+++ b/libs/ardour/ardour/region_factory.h
@@ -25,6 +25,7 @@
 #include <glibmm/thread.h>
 
 #include "pbd/id.h"
+#include "pbd/property_list.h"
 #include "pbd/signals.h"
 
 #include "ardour/types.h"
diff --git a/libs/ardour/ardour/route_group_member.h b/libs/ardour/ardour/route_group_member.h
index 3cc8e2aaf8..2665c719e6 100644
--- a/libs/ardour/ardour/route_group_member.h
+++ b/libs/ardour/ardour/route_group_member.h
@@ -20,6 +20,7 @@
 #ifndef __libardour_route_group_member_h__
 #define __libardour_route_group_member_h__
 
+#include "pbd/signals.h"
 
 namespace ARDOUR  {
 
diff --git a/libs/ardour/ardour/sndfileimportable.h b/libs/ardour/ardour/sndfileimportable.h
index b146d3231c..8612e264c4 100644
--- a/libs/ardour/ardour/sndfileimportable.h
+++ b/libs/ardour/ardour/sndfileimportable.h
@@ -22,7 +22,6 @@
 
 #include <boost/shared_ptr.hpp>
 #include <sndfile.h>
-#include "pbd/failed_constructor.h"
 #include "ardour/types.h"
 #include "ardour/importable_source.h"
 
diff --git a/libs/ardour/ardour/tempo_map_importer.h b/libs/ardour/ardour/tempo_map_importer.h
index beacbc1e01..57c7402781 100644
--- a/libs/ardour/ardour/tempo_map_importer.h
+++ b/libs/ardour/ardour/tempo_map_importer.h
@@ -27,11 +27,11 @@
 
 #include "ardour/element_importer.h"
 #include "ardour/element_import_handler.h"
-#include "ardour/tempo.h"
-#include "ardour/types.h"
 
 namespace ARDOUR {
 
+class Session;
+
 class TempoMapImportHandler : public ElementImportHandler
 {
   public:
diff --git a/libs/ardour/audio_diskstream.cc b/libs/ardour/audio_diskstream.cc
index c38901f430..8c5b606388 100644
--- a/libs/ardour/audio_diskstream.cc
+++ b/libs/ardour/audio_diskstream.cc
@@ -37,29 +37,24 @@
 #include "pbd/stateful_diff_command.h"
 
 #include "ardour/analyser.h"
-#include "ardour/ardour.h"
 #include "ardour/audio_buffer.h"
 #include "ardour/audio_diskstream.h"
 #include "ardour/audio_port.h"
 #include "ardour/audioengine.h"
 #include "ardour/audiofilesource.h"
-
 #include "ardour/audioplaylist.h"
 #include "ardour/audioregion.h"
 #include "ardour/butler.h"
-#include "ardour/configuration.h"
-#include "ardour/cycle_timer.h"
 #include "ardour/debug.h"
 #include "ardour/io.h"
 #include "ardour/playlist_factory.h"
 #include "ardour/region_factory.h"
-#include "ardour/send.h"
 #include "ardour/session.h"
+#include "ardour/session_playlists.h"
 #include "ardour/source_factory.h"
 #include "ardour/track.h"
+#include "ardour/types.h"
 #include "ardour/utils.h"
-#include "ardour/session_playlists.h"
-#include "ardour/route.h"
 
 #include "i18n.h"
 #include <locale.h>
diff --git a/libs/ardour/audio_playlist.cc b/libs/ardour/audio_playlist.cc
index da6f84a4ae..25fad6122f 100644
--- a/libs/ardour/audio_playlist.cc
+++ b/libs/ardour/audio_playlist.cc
@@ -23,12 +23,10 @@
 
 #include "ardour/types.h"
 #include "ardour/debug.h"
-#include "ardour/configuration.h"
 #include "ardour/audioplaylist.h"
 #include "ardour/audioregion.h"
 #include "ardour/region_sorters.h"
 #include "ardour/session.h"
-#include "pbd/enumwriter.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/audio_playlist_importer.cc b/libs/ardour/audio_playlist_importer.cc
index 1c119e0ed7..34d46915f1 100644
--- a/libs/ardour/audio_playlist_importer.cc
+++ b/libs/ardour/audio_playlist_importer.cc
@@ -28,7 +28,6 @@
 
 #include "ardour/audio_region_importer.h"
 #include "ardour/session.h"
-#include "ardour/playlist.h"
 #include "ardour/playlist_factory.h"
 #include "ardour/session_playlists.h"
 
diff --git a/libs/ardour/audio_playlist_source.cc b/libs/ardour/audio_playlist_source.cc
index 141a8495f9..4ba820d716 100644
--- a/libs/ardour/audio_playlist_source.cc
+++ b/libs/ardour/audio_playlist_source.cc
@@ -27,18 +27,13 @@
 #include <glibmm/miscutils.h>
 
 #include "pbd/error.h"
-#include "pbd/convert.h"
-#include "pbd/enumwriter.h"
 
 #include "ardour/audioplaylist.h"
 #include "ardour/audio_playlist_source.h"
 #include "ardour/audioregion.h"
-#include "ardour/debug.h"
 #include "ardour/filename_extensions.h"
 #include "ardour/session.h"
 #include "ardour/session_directory.h"
-#include "ardour/session_playlists.h"
-#include "ardour/source_factory.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/audio_port.cc b/libs/ardour/audio_port.cc
index ae64d797c9..48a757fb42 100644
--- a/libs/ardour/audio_port.cc
+++ b/libs/ardour/audio_port.cc
@@ -20,10 +20,9 @@
 
 #include "pbd/stacktrace.h"
 
-#include "ardour/audio_port.h"
-#include "ardour/audioengine.h"
-#include "ardour/data_type.h"
 #include "ardour/audio_buffer.h"
+#include "ardour/audio_port.h"
+#include "ardour/data_type.h"
 
 using namespace ARDOUR;
 using namespace std;
diff --git a/libs/ardour/audio_region_importer.cc b/libs/ardour/audio_region_importer.cc
index 6f6bd82501..91c362d042 100644
--- a/libs/ardour/audio_region_importer.cc
+++ b/libs/ardour/audio_region_importer.cc
@@ -28,7 +28,6 @@
 
 #include "ardour/session.h"
 #include "ardour/region.h"
-#include "ardour/source_factory.h"
 #include "ardour/region_factory.h"
 #include "ardour/session_directory.h"
 
diff --git a/libs/ardour/audio_track.cc b/libs/ardour/audio_track.cc
index b548b3a444..293ca0d2c1 100644
--- a/libs/ardour/audio_track.cc
+++ b/libs/ardour/audio_track.cc
@@ -19,9 +19,9 @@
 
 #include <boost/scoped_array.hpp>
 
-#include "pbd/error.h"
-#include "pbd/enumwriter.h"
 #include "pbd/boost_debug.h"
+#include "pbd/enumwriter.h"
+#include "pbd/error.h"
 
 #include "evoral/Curve.hpp"
 
@@ -30,23 +30,18 @@
 #include "ardour/audio_diskstream.h"
 #include "ardour/audio_track.h"
 #include "ardour/audioplaylist.h"
-#include "ardour/audioregion.h"
-#include "ardour/audiosource.h"
 #include "ardour/buffer_set.h"
-#include "ardour/io_processor.h"
-#include "ardour/panner.h"
-#include "ardour/meter.h"
-#include "ardour/playlist_factory.h"
-#include "ardour/plugin_insert.h"
-#include "ardour/port_insert.h"
-#include "ardour/processor.h"
-#include "ardour/region_factory.h"
-#include "ardour/route_group_specialized.h"
-#include "ardour/session.h"
-#include "ardour/utils.h"
-#include "ardour/session_playlists.h"
 #include "ardour/delivery.h"
 #include "ardour/meter.h"
+#include "ardour/playlist_factory.h"
+#include "ardour/processor.h"
+#include "ardour/region.h"
+#include "ardour/region_factory.h"
+#include "ardour/session.h"
+#include "ardour/session_playlists.h"
+#include "ardour/source.h"
+#include "ardour/utils.h"
+
 #include "i18n.h"
 
 using namespace std;
diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index 372581f4e6..7c3beb6c13 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -38,24 +38,16 @@
 #include "midi++/mmc.h"
 #include "midi++/manager.h"
 
-#include "ardour/amp.h"
 #include "ardour/audio_port.h"
 #include "ardour/audioengine.h"
 #include "ardour/buffer.h"
-#include "ardour/buffer_set.h"
 #include "ardour/cycle_timer.h"
-#include "ardour/event_type_map.h"
-#include "ardour/internal_return.h"
 #include "ardour/internal_send.h"
-#include "ardour/io.h"
 #include "ardour/meter.h"
 #include "ardour/midi_port.h"
-#include "ardour/process_thread.h"
 #include "ardour/port.h"
-#include "ardour/port_set.h"
+#include "ardour/process_thread.h"
 #include "ardour/session.h"
-#include "ardour/timestamps.h"
-#include "ardour/utils.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/audiofilesource.cc b/libs/ardour/audiofilesource.cc
index 3ae0db2101..e101f5b25b 100644
--- a/libs/ardour/audiofilesource.cc
+++ b/libs/ardour/audiofilesource.cc
@@ -46,11 +46,8 @@
 
 #include "ardour/audiofilesource.h"
 #include "ardour/debug.h"
-#include "ardour/sndfile_helpers.h"
 #include "ardour/sndfilesource.h"
 #include "ardour/session.h"
-#include "ardour/session_directory.h"
-#include "ardour/source_factory.h"
 #include "ardour/filename_extensions.h"
 
 // if these headers come before sigc++ is included
diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index 9cbbdcfe4e..8a8f42165c 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -37,7 +37,6 @@
 #include "evoral/Curve.hpp"
 
 #include "ardour/audioregion.h"
-#include "ardour/debug.h"
 #include "ardour/session.h"
 #include "ardour/dB.h"
 #include "ardour/playlist.h"
diff --git a/libs/ardour/audiosource.cc b/libs/ardour/audiosource.cc
index 8fe3b8d8c3..e33a3d30de 100644
--- a/libs/ardour/audiosource.cc
+++ b/libs/ardour/audiosource.cc
@@ -35,13 +35,9 @@
 #include <glibmm/miscutils.h>
 
 #include "pbd/xml++.h"
-#include "pbd/pthread_utils.h"
 
 #include "ardour/audiosource.h"
-#include "ardour/audio_diskstream.h"
-#include "ardour/cycle_timer.h"
-#include "ardour/session.h"
-#include "ardour/transient_detector.h"
+#include "ardour/rc_configuration.h"
 #include "ardour/runtime_functions.h"
 
 #include "i18n.h"
diff --git a/libs/ardour/auditioner.cc b/libs/ardour/auditioner.cc
index 71730ad0bb..6c143568c4 100644
--- a/libs/ardour/auditioner.cc
+++ b/libs/ardour/auditioner.cc
@@ -30,8 +30,6 @@
 #include "ardour/auditioner.h"
 #include "ardour/audioplaylist.h"
 #include "ardour/audio_port.h"
-#include "ardour/panner_shell.h"
-#include "ardour/panner.h"
 #include "ardour/data_type.h"
 #include "ardour/region_factory.h"
 
diff --git a/libs/ardour/automatable.cc b/libs/ardour/automatable.cc
index 6d8114939d..d0a605bcd9 100644
--- a/libs/ardour/automatable.cc
+++ b/libs/ardour/automatable.cc
@@ -17,27 +17,22 @@
 
 */
 
-#include "ardour/ardour.h"
 #include <fstream>
-#include <inttypes.h>
 #include <cstdio>
 #include <errno.h>
 
 #include <glibmm/miscutils.h>
 
 #include "pbd/error.h"
-#include "pbd/enumwriter.h"
-#include "pbd/stacktrace.h"
 
 #include "midi++/names.h"
 
-#include "ardour/automatable.h"
 #include "ardour/amp.h"
+#include "ardour/automatable.h"
 #include "ardour/event_type_map.h"
 #include "ardour/midi_track.h"
-#include "ardour/pannable.h"
-#include "ardour/panner.h"
 #include "ardour/pan_controllable.h"
+#include "ardour/pannable.h"
 #include "ardour/plugin_insert.h"
 #include "ardour/session.h"
 
diff --git a/libs/ardour/automation_control.cc b/libs/ardour/automation_control.cc
index fd4a228037..05463dcdd0 100644
--- a/libs/ardour/automation_control.cc
+++ b/libs/ardour/automation_control.cc
@@ -19,7 +19,7 @@
 */
 
 #include <iostream>
-#include "ardour/automatable.h"
+
 #include "ardour/automation_control.h"
 #include "ardour/event_type_map.h"
 #include "ardour/session.h"
@@ -28,7 +28,6 @@ using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
-
 AutomationControl::AutomationControl(
 		ARDOUR::Session& session,
 		const Evoral::Parameter& parameter,
diff --git a/libs/ardour/broadcast_info.cc b/libs/ardour/broadcast_info.cc
index d31104d545..436c30c797 100644
--- a/libs/ardour/broadcast_info.cc
+++ b/libs/ardour/broadcast_info.cc
@@ -26,12 +26,9 @@
 #include <glibmm.h>
 
 #include "ardour/svn_revision.h"
-#include "ardour/ardour.h"
 #include "ardour/session.h"
 #include "ardour/session_metadata.h"
 
-#include "pbd/convert.h"
-
 using namespace PBD;
 
 namespace ARDOUR
diff --git a/libs/ardour/buffer_manager.cc b/libs/ardour/buffer_manager.cc
index 5a2d941eaf..b30fd6ebb6 100644
--- a/libs/ardour/buffer_manager.cc
+++ b/libs/ardour/buffer_manager.cc
@@ -22,7 +22,6 @@
 #include "pbd/compose.h"
 
 #include "ardour/buffer_manager.h"
-#include "ardour/debug.h"
 #include "ardour/thread_buffers.h"
 
 using namespace ARDOUR;
diff --git a/libs/ardour/buffer_set.cc b/libs/ardour/buffer_set.cc
index 156cf4dd3f..55356bdecb 100644
--- a/libs/ardour/buffer_set.cc
+++ b/libs/ardour/buffer_set.cc
@@ -33,7 +33,6 @@
 #include "ardour/midi_buffer.h"
 #include "ardour/port.h"
 #include "ardour/port_set.h"
-#include "ardour/audioengine.h"
 #ifdef LV2_SUPPORT
 #include "ardour/lv2_plugin.h"
 #include "lv2_evbuf.h"
diff --git a/libs/ardour/bundle.cc b/libs/ardour/bundle.cc
index 6180836bd2..5040882b7a 100644
--- a/libs/ardour/bundle.cc
+++ b/libs/ardour/bundle.cc
@@ -19,12 +19,9 @@
 
 #include <algorithm>
 
-#include "pbd/failed_constructor.h"
-#include "ardour/ardour.h"
 #include "ardour/bundle.h"
 #include "ardour/audioengine.h"
 #include "ardour/port.h"
-#include "pbd/xml++.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/callback.cc b/libs/ardour/callback.cc
index 85449dac03..37442fce0c 100644
--- a/libs/ardour/callback.cc
+++ b/libs/ardour/callback.cc
@@ -16,7 +16,6 @@
 #include "pbd/strsplit.h"
 #include "pbd/convert.h"
 
-#include "ardour/callback.h"
 #include "ardour/filesystem_paths.h"
 
 using namespace std;
diff --git a/libs/ardour/control_protocol_manager.cc b/libs/ardour/control_protocol_manager.cc
index 2931fe46e5..475781f3c5 100644
--- a/libs/ardour/control_protocol_manager.cc
+++ b/libs/ardour/control_protocol_manager.cc
@@ -28,7 +28,6 @@
 #include "control_protocol/control_protocol.h"
 
 #include "ardour/debug.h"
-#include "ardour/session.h"
 #include "ardour/control_protocol_manager.h"
 #include "ardour/control_protocol_search_path.h"
 
diff --git a/libs/ardour/default_click.cc b/libs/ardour/default_click.cc
index 242e5c2918..fd23f0166d 100644
--- a/libs/ardour/default_click.cc
+++ b/libs/ardour/default_click.cc
@@ -18,8 +18,8 @@
 
 */
 
-#include "ardour/ardour.h"
 #include "ardour/session.h"
+#include "ardour/types.h"
 
 using namespace ARDOUR;
 
diff --git a/libs/ardour/delivery.cc b/libs/ardour/delivery.cc
index 86ce419340..b58e7b4471 100644
--- a/libs/ardour/delivery.cc
+++ b/libs/ardour/delivery.cc
@@ -22,27 +22,22 @@
 #include "pbd/enumwriter.h"
 #include "pbd/convert.h"
 
-#include "ardour/midi_buffer.h"
-
+#include "ardour/amp.h"
+#include "ardour/audioengine.h"
+#include "ardour/buffer_set.h"
 #include "ardour/debug.h"
 #include "ardour/delivery.h"
-#include "ardour/audio_buffer.h"
-#include "ardour/audio_port.h"
-#include "ardour/amp.h"
-#include "ardour/buffer_set.h"
-#include "ardour/configuration.h"
 #include "ardour/io.h"
-#include "ardour/meter.h"
 #include "ardour/mute_master.h"
-#include "ardour/panner.h"
-#include "ardour/panner_shell.h"
 #include "ardour/pannable.h"
+#include "ardour/panner_shell.h"
 #include "ardour/port.h"
 #include "ardour/session.h"
-#include "ardour/audioengine.h"
 
 #include "i18n.h"
 
+namespace ARDOUR { class Panner; }
+
 using namespace std;
 using namespace PBD;
 using namespace ARDOUR;
diff --git a/libs/ardour/diskstream.cc b/libs/ardour/diskstream.cc
index 6e23eb81aa..7a0b0a81b1 100644
--- a/libs/ardour/diskstream.cc
+++ b/libs/ardour/diskstream.cc
@@ -31,7 +31,6 @@
 #include <sys/stat.h>
 #include <sys/mman.h>
 
-
 #include <glibmm/thread.h>
 
 #include "pbd/error.h"
@@ -40,22 +39,12 @@
 #include "pbd/xml++.h"
 #include "pbd/stacktrace.h"
 
-#include "ardour/ardour.h"
-#include "ardour/audioengine.h"
 #include "ardour/debug.h"
 #include "ardour/diskstream.h"
-#include "ardour/utils.h"
-#include "ardour/configuration.h"
-#include "ardour/audiofilesource.h"
-#include "ardour/send.h"
-#include "ardour/pannable.h"
-#include "ardour/panner_shell.h"
-#include "ardour/playlist.h"
-#include "ardour/cycle_timer.h"
-#include "ardour/region.h"
-#include "ardour/panner.h"
-#include "ardour/session.h"
 #include "ardour/io.h"
+#include "ardour/pannable.h"
+#include "ardour/playlist.h"
+#include "ardour/session.h"
 #include "ardour/track.h"
 
 #include "i18n.h"
diff --git a/libs/ardour/enums.cc b/libs/ardour/enums.cc
index c0d6107639..afe92ed5f7 100644
--- a/libs/ardour/enums.cc
+++ b/libs/ardour/enums.cc
@@ -20,22 +20,18 @@
 #include "pbd/enumwriter.h"
 #include "midi++/types.h"
 
-#include "ardour/audiofilesource.h"
-#include "ardour/audioregion.h"
 #include "ardour/delivery.h"
 #include "ardour/diskstream.h"
+#include "ardour/export_channel.h"
 #include "ardour/export_filename.h"
 #include "ardour/export_format_base.h"
 #include "ardour/export_profile_manager.h"
-#include "ardour/export_channel_configuration.h"
 #include "ardour/io.h"
 #include "ardour/location.h"
 #include "ardour/midi_model.h"
-#include "ardour/midi_track.h"
 #include "ardour/mute_master.h"
-#include "ardour/panner.h"
-#include "ardour/route_group.h"
 #include "ardour/session.h"
+#include "ardour/source.h"
 #include "ardour/track.h"
 #include "ardour/types.h"
 
diff --git a/libs/ardour/export_channel_configuration.cc b/libs/ardour/export_channel_configuration.cc
index 9487d021b4..77b56272d6 100644
--- a/libs/ardour/export_channel_configuration.cc
+++ b/libs/ardour/export_channel_configuration.cc
@@ -20,16 +20,6 @@
 
 #include "ardour/export_channel_configuration.h"
 
-#include "ardour/export_handler.h"
-#include "ardour/export_filename.h"
-#include "ardour/export_timespan.h"
-
-#include "ardour/audio_port.h"
-#include "ardour/export_failed.h"
-#include "ardour/midi_port.h"
-#include "ardour/session.h"
-#include "ardour/audioengine.h"
-
 #include "pbd/convert.h"
 #include "pbd/enumwriter.h"
 #include "pbd/pthread_utils.h"
diff --git a/libs/ardour/export_filename.cc b/libs/ardour/export_filename.cc
index d5309bd535..f53dfbcbf6 100644
--- a/libs/ardour/export_filename.cc
+++ b/libs/ardour/export_filename.cc
@@ -30,7 +30,6 @@
 #include "ardour/export_timespan.h"
 #include "ardour/export_format_specification.h"
 #include "ardour/export_channel_configuration.h"
-#include "ardour/export_failed.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/export_format_manager.cc b/libs/ardour/export_format_manager.cc
index 23a77925fe..ff115d4447 100644
--- a/libs/ardour/export_format_manager.cc
+++ b/libs/ardour/export_format_manager.cc
@@ -20,7 +20,6 @@
 
 #include "ardour/export_format_manager.h"
 
-#include "ardour/types.h"
 #include "ardour/export_format_specification.h"
 #include "ardour/export_format_compatibility.h"
 
diff --git a/libs/ardour/export_graph_builder.cc b/libs/ardour/export_graph_builder.cc
index 8152ff0c20..fbb5d0f98a 100644
--- a/libs/ardour/export_graph_builder.cc
+++ b/libs/ardour/export_graph_builder.cc
@@ -17,7 +17,6 @@
 #include "ardour/export_format_specification.h"
 #include "ardour/export_timespan.h"
 #include "ardour/sndfile_helpers.h"
-#include "ardour/utils.h"
 
 #include "pbd/filesystem.h"
 #include "pbd/cpus.h"
diff --git a/libs/ardour/export_handler.cc b/libs/ardour/export_handler.cc
index f44450d3f0..fb65cebff0 100644
--- a/libs/ardour/export_handler.cc
+++ b/libs/ardour/export_handler.cc
@@ -26,15 +26,12 @@
 #include "pbd/convert.h"
 #include "pbd/filesystem.h"
 
-#include "ardour/ardour.h"
-#include "ardour/configuration.h"
 #include "ardour/export_graph_builder.h"
 #include "ardour/export_timespan.h"
 #include "ardour/export_channel_configuration.h"
 #include "ardour/export_status.h"
 #include "ardour/export_format_specification.h"
 #include "ardour/export_filename.h"
-#include "ardour/export_failed.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/export_timespan.cc b/libs/ardour/export_timespan.cc
index 20b535836c..3b2021355e 100644
--- a/libs/ardour/export_timespan.cc
+++ b/libs/ardour/export_timespan.cc
@@ -20,10 +20,6 @@
 
 #include "ardour/export_timespan.h"
 
-#include "ardour/export_channel_configuration.h"
-#include "ardour/export_filename.h"
-#include "ardour/export_failed.h"
-
 namespace ARDOUR
 {
 
diff --git a/libs/ardour/file_source.cc b/libs/ardour/file_source.cc
index be4ded9a2c..a7e3585e64 100644
--- a/libs/ardour/file_source.cc
+++ b/libs/ardour/file_source.cc
@@ -38,12 +38,11 @@
 #include <glibmm/fileutils.h>
 #include <glibmm/thread.h>
 
+#include "ardour/data_type.h"
 #include "ardour/file_source.h"
-#include "ardour/directory_names.h"
 #include "ardour/session.h"
-#include "ardour/session_directory.h"
-#include "ardour/source_factory.h"
-#include "ardour/filename_extensions.h"
+#include "ardour/source.h"
+#include "ardour/utils.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/filename_extensions.cc b/libs/ardour/filename_extensions.cc
index c09a8c481c..0684a13083 100644
--- a/libs/ardour/filename_extensions.cc
+++ b/libs/ardour/filename_extensions.cc
@@ -1,6 +1,5 @@
 #include "ardour/filename_extensions.h"
 
-#include <stdint.h>
 #include "i18n.h"
 
 namespace ARDOUR {
diff --git a/libs/ardour/filter.cc b/libs/ardour/filter.cc
index 8067edf14e..67aa840cad 100644
--- a/libs/ardour/filter.cc
+++ b/libs/ardour/filter.cc
@@ -21,15 +21,16 @@
 #include <cerrno>
 
 #include "pbd/basename.h"
-#include "ardour/sndfilesource.h"
-#include "ardour/smf_source.h"
-#include "ardour/session.h"
-#include "ardour/region.h"
-#include "ardour/filter.h"
-#include "ardour/region_factory.h"
-#include "ardour/source_factory.h"
+
 #include "ardour/analyser.h"
+#include "ardour/audiofilesource.h"
 #include "ardour/audioregion.h"
+#include "ardour/filter.h"
+#include "ardour/region.h"
+#include "ardour/region_factory.h"
+#include "ardour/session.h"
+#include "ardour/smf_source.h"
+#include "ardour/source_factory.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/find_session.cc b/libs/ardour/find_session.cc
index c635b86545..4469b4e59d 100644
--- a/libs/ardour/find_session.cc
+++ b/libs/ardour/find_session.cc
@@ -10,7 +10,6 @@
 #include "pbd/compose.h"
 #include "pbd/error.h"
 
-#include "ardour/session_utils.h"
 #include "ardour/filename_extensions.h"
 #include "ardour/utils.h"
 
@@ -19,8 +18,10 @@
 using namespace std;
 using namespace PBD;
 
+namespace ARDOUR {
+
 int
-ARDOUR::find_session (string str, string& path, string& snapshot, bool& isnew)
+find_session (string str, string& path, string& snapshot, bool& isnew)
 {
 	struct stat statbuf;
 	char buf[PATH_MAX+1];
@@ -164,3 +165,5 @@ ARDOUR::find_session (string str, string& path, string& snapshot, bool& isnew)
 
 	return 0;
 }
+
+}  // namespace ARDOUR
diff --git a/libs/ardour/globals.cc b/libs/ardour/globals.cc
index 0e0c508a58..56aab1e12d 100644
--- a/libs/ardour/globals.cc
+++ b/libs/ardour/globals.cc
@@ -62,31 +62,25 @@
 #include "midi++/mmc.h"
 
 #include "ardour/analyser.h"
-#include "ardour/ardour.h"
 #include "ardour/audio_library.h"
 #include "ardour/audioengine.h"
+#include "ardour/audioplaylist.h"
 #include "ardour/audioregion.h"
-#include "ardour/audiosource.h"
 #include "ardour/buffer_manager.h"
 #include "ardour/control_protocol_manager.h"
-#include "ardour/dB.h"
-#include "ardour/debug.h"
 #include "ardour/filesystem_paths.h"
 #include "ardour/midi_region.h"
 #include "ardour/mix.h"
-#include "ardour/audioplaylist.h"
 #include "ardour/panner_manager.h"
 #include "ardour/plugin_manager.h"
 #include "ardour/process_thread.h"
 #include "ardour/profile.h"
-#include "ardour/region.h"
 #include "ardour/rc_configuration.h"
+#include "ardour/region.h"
 #include "ardour/route_group.h"
 #include "ardour/runtime_functions.h"
-#include "ardour/session.h"
 #include "ardour/session_event.h"
 #include "ardour/source_factory.h"
-#include "ardour/utils.h"
 
 #include "audiographer/routines.h"
 
diff --git a/libs/ardour/import.cc b/libs/ardour/import.cc
index 0c4256e1f4..17b396961a 100644
--- a/libs/ardour/import.cc
+++ b/libs/ardour/import.cc
@@ -52,6 +52,7 @@
 #include "ardour/import_status.h"
 #include "ardour/region_factory.h"
 #include "ardour/resampled_source.h"
+#include "ardour/runtime_functions.h"
 #include "ardour/session.h"
 #include "ardour/session_directory.h"
 #include "ardour/smf_source.h"
diff --git a/libs/ardour/internal_return.cc b/libs/ardour/internal_return.cc
index 6a3d20e5c9..ad2ed81194 100644
--- a/libs/ardour/internal_return.cc
+++ b/libs/ardour/internal_return.cc
@@ -18,14 +18,8 @@
 
 #include <glibmm/thread.h>
 
-#include "pbd/failed_constructor.h"
-
-#include "ardour/audio_buffer.h"
 #include "ardour/internal_return.h"
-#include "ardour/mute_master.h"
-#include "ardour/session.h"
 #include "ardour/internal_send.h"
-#include "ardour/audioengine.h"
 
 using namespace std;
 using namespace ARDOUR;
diff --git a/libs/ardour/internal_send.cc b/libs/ardour/internal_send.cc
index dfb0204c8c..671936b0ff 100644
--- a/libs/ardour/internal_send.cc
+++ b/libs/ardour/internal_send.cc
@@ -25,7 +25,6 @@
 #include "ardour/internal_return.h"
 #include "ardour/internal_send.h"
 #include "ardour/meter.h"
-#include "ardour/panner.h"
 #include "ardour/panner_shell.h"
 #include "ardour/route.h"
 #include "ardour/session.h"
@@ -33,6 +32,8 @@
 
 #include "i18n.h"
 
+namespace ARDOUR { class MuteMaster; class Pannable; }
+
 using namespace PBD;
 using namespace ARDOUR;
 using namespace std;
diff --git a/libs/ardour/io.cc b/libs/ardour/io.cc
index 26432c66ef..da79301a31 100644
--- a/libs/ardour/io.cc
+++ b/libs/ardour/io.cc
@@ -34,17 +34,12 @@
 
 #include "ardour/audioengine.h"
 #include "ardour/buffer.h"
+#include "ardour/buffer_set.h"
 #include "ardour/debug.h"
 #include "ardour/io.h"
-#include "ardour/route.h"
 #include "ardour/port.h"
-#include "ardour/audio_port.h"
-#include "ardour/midi_port.h"
+#include "ardour/route.h"
 #include "ardour/session.h"
-#include "ardour/cycle_timer.h"
-#include "ardour/buffer_set.h"
-#include "ardour/meter.h"
-#include "ardour/amp.h"
 #include "ardour/user_bundle.h"
 
 #include "i18n.h"
diff --git a/libs/ardour/io_processor.cc b/libs/ardour/io_processor.cc
index d5e0f3e0eb..fd47e1c06c 100644
--- a/libs/ardour/io_processor.cc
+++ b/libs/ardour/io_processor.cc
@@ -17,25 +17,20 @@
 
 */
 
-#include <fstream>
-#include <algorithm>
+#include <list>
 #include <string>
-#include <cerrno>
-#include <unistd.h>
-#include <sstream>
-
 
 #include "pbd/xml++.h"
 #include "pbd/enumwriter.h"
 
-#include "ardour/io_processor.h"
-#include "ardour/session.h"
-#include "ardour/utils.h"
-#include "ardour/send.h"
-#include "ardour/port_insert.h"
-#include "ardour/plugin_insert.h"
+#include "ardour/chan_count.h"
+#include "ardour/data_type.h"
 #include "ardour/io.h"
+#include "ardour/io_processor.h"
+#include "ardour/processor.h"
 #include "ardour/route.h"
+#include "ardour/session_object.h"
+#include "ardour/types.h"
 
 #include "i18n.h"
 
@@ -43,6 +38,8 @@ using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
+namespace ARDOUR { class Session; }
+
 /* create an IOProcessor that proxies to a new IO object */
 
 IOProcessor::IOProcessor (Session& s, bool with_input, bool with_output,
diff --git a/libs/ardour/jack_slave.cc b/libs/ardour/jack_slave.cc
index 116ccdd145..4c2da4c6c4 100644
--- a/libs/ardour/jack_slave.cc
+++ b/libs/ardour/jack_slave.cc
@@ -24,9 +24,6 @@
 #include <jack/transport.h>
 
 #include "ardour/slave.h"
-#include "ardour/session.h"
-
-#include "i18n.h"
 
 using namespace std;
 using namespace ARDOUR;
diff --git a/libs/ardour/ladspa_plugin.cc b/libs/ardour/ladspa_plugin.cc
index 3a25eab384..1b3a5ea2e3 100644
--- a/libs/ardour/ladspa_plugin.cc
+++ b/libs/ardour/ladspa_plugin.cc
@@ -37,9 +37,7 @@
 
 #include "midi++/manager.h"
 
-#include "ardour/ardour.h"
 #include "ardour/session.h"
-#include "ardour/audioengine.h"
 #include "ardour/ladspa_plugin.h"
 #include "ardour/buffer_set.h"
 #include "ardour/audio_buffer.h"
diff --git a/libs/ardour/lv2_plugin.cc b/libs/ardour/lv2_plugin.cc
index 46c09a1227..50552d2eb8 100644
--- a/libs/ardour/lv2_plugin.cc
+++ b/libs/ardour/lv2_plugin.cc
@@ -31,13 +31,11 @@
 
 #include "pbd/compose.h"
 #include "pbd/error.h"
-#include "pbd/pathscanner.h"
-#include "pbd/stl_delete.h"
 #include "pbd/xml++.h"
 
 #include "libardour-config.h"
 
-#include "ardour/ardour.h"
+#include "ardour/types.h"
 #include "ardour/audio_buffer.h"
 #include "ardour/audioengine.h"
 #include "ardour/debug.h"
diff --git a/libs/ardour/meter.cc b/libs/ardour/meter.cc
index 5957d570b9..3b49c97d27 100644
--- a/libs/ardour/meter.cc
+++ b/libs/ardour/meter.cc
@@ -16,15 +16,15 @@
     675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
-#include "ardour/meter.h"
 #include <algorithm>
 #include <cmath>
-#include "ardour/buffer_set.h"
-#include "ardour/peak.h"
-#include "ardour/dB.h"
-#include "ardour/session.h"
-#include "ardour/midi_buffer.h"
+
 #include "ardour/audio_buffer.h"
+#include "ardour/buffer_set.h"
+#include "ardour/dB.h"
+#include "ardour/meter.h"
+#include "ardour/midi_buffer.h"
+#include "ardour/rc_configuration.h"
 #include "ardour/runtime_functions.h"
 
 using namespace std;
diff --git a/libs/ardour/midi_clock_slave.cc b/libs/ardour/midi_clock_slave.cc
index 87ea05738d..05c0e9e2ac 100644
--- a/libs/ardour/midi_clock_slave.cc
+++ b/libs/ardour/midi_clock_slave.cc
@@ -32,12 +32,8 @@
 
 #include "ardour/debug.h"
 #include "ardour/slave.h"
-#include "ardour/session.h"
-#include "ardour/audioengine.h"
-#include "ardour/cycles.h"
 #include "ardour/tempo.h"
 
-
 #include "i18n.h"
 
 using namespace std;
diff --git a/libs/ardour/midi_diskstream.cc b/libs/ardour/midi_diskstream.cc
index 9b3b619d1c..a8757d7575 100644
--- a/libs/ardour/midi_diskstream.cc
+++ b/libs/ardour/midi_diskstream.cc
@@ -38,11 +38,8 @@
 #include "pbd/stateful_diff_command.h"
 #include "pbd/stacktrace.h"
 
-#include "ardour/ardour.h"
 #include "ardour/audioengine.h"
 #include "ardour/butler.h"
-#include "ardour/configuration.h"
-#include "ardour/cycle_timer.h"
 #include "ardour/debug.h"
 #include "ardour/io.h"
 #include "ardour/midi_diskstream.h"
@@ -52,11 +49,10 @@
 #include "ardour/midi_region.h"
 #include "ardour/playlist_factory.h"
 #include "ardour/region_factory.h"
-#include "ardour/route.h"
-#include "ardour/send.h"
 #include "ardour/session.h"
 #include "ardour/session_playlists.h"
 #include "ardour/smf_source.h"
+#include "ardour/types.h"
 #include "ardour/utils.h"
 
 #include "midi++/types.h"
diff --git a/libs/ardour/midi_model.cc b/libs/ardour/midi_model.cc
index 40d2f600c8..a914a0d887 100644
--- a/libs/ardour/midi_model.cc
+++ b/libs/ardour/midi_model.cc
@@ -38,7 +38,6 @@
 #include "ardour/midi_source.h"
 #include "ardour/midi_state_tracker.h"
 #include "ardour/session.h"
-#include "ardour/smf_source.h"
 #include "ardour/types.h"
 
 #include "i18n.h"
diff --git a/libs/ardour/midi_patch_manager.cc b/libs/ardour/midi_patch_manager.cc
index d3d080a179..58e33d2d53 100644
--- a/libs/ardour/midi_patch_manager.cc
+++ b/libs/ardour/midi_patch_manager.cc
@@ -20,7 +20,6 @@
 
 #include <boost/shared_ptr.hpp>
 
-#include "pbd/compose.h"
 #include "pbd/file_utils.h"
 #include "pbd/error.h"
 
@@ -29,8 +28,6 @@
 #include "ardour/midi_patch_manager.h"
 #include "ardour/midi_patch_search_path.h"
 
-#include "i18n.h"
-
 using namespace std;
 using namespace ARDOUR;
 using namespace MIDI;
diff --git a/libs/ardour/midi_playlist.cc b/libs/ardour/midi_playlist.cc
index 9aa36304a6..9c1e338b6c 100644
--- a/libs/ardour/midi_playlist.cc
+++ b/libs/ardour/midi_playlist.cc
@@ -25,17 +25,12 @@
 
 #include <stdlib.h>
 
-#include "pbd/error.h"
-
 #include "evoral/EventList.hpp"
 
-#include "ardour/configuration.h"
 #include "ardour/debug.h"
 #include "ardour/midi_model.h"
 #include "ardour/midi_playlist.h"
 #include "ardour/midi_region.h"
-#include "ardour/midi_ring_buffer.h"
-#include "ardour/session.h"
 #include "ardour/types.h"
 
 #include "i18n.h"
diff --git a/libs/ardour/midi_playlist_source.cc b/libs/ardour/midi_playlist_source.cc
index 957531f520..5dfbf955c6 100644
--- a/libs/ardour/midi_playlist_source.cc
+++ b/libs/ardour/midi_playlist_source.cc
@@ -20,25 +20,10 @@
 #include "libardour-config.h"
 #endif
 
-#include <vector>
-#include <cstdio>
-
-#include <glibmm/fileutils.h>
-#include <glibmm/miscutils.h>
-
 #include "pbd/error.h"
-#include "pbd/convert.h"
-#include "pbd/enumwriter.h"
 
 #include "ardour/midi_playlist.h"
 #include "ardour/midi_playlist_source.h"
-#include "ardour/midi_region.h"
-#include "ardour/debug.h"
-#include "ardour/filename_extensions.h"
-#include "ardour/session.h"
-#include "ardour/session_directory.h"
-#include "ardour/session_playlists.h"
-#include "ardour/source_factory.h"
 
 #include "i18n.h"
 
@@ -46,6 +31,17 @@ using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
+namespace ARDOUR {
+class MidiStateTracker;
+class Session;
+template <typename T> class MidiRingBuffer;
+}
+
+namespace Evoral {
+template <typename T> class EventSink;
+template <typename Time> class Event;
+}
+
 /*******************************************************************************
 As of May 2011, it appears too complex to support compound regions for MIDI
 because of the need to be able to edit the data represented by the region.  It
@@ -98,7 +94,6 @@ MidiPlaylistSource::get_state ()
 	return node;
 }
 
-
 int
 MidiPlaylistSource::set_state (const XMLNode& node, int version)
 {
diff --git a/libs/ardour/midi_region.cc b/libs/ardour/midi_region.cc
index f9f1867686..d52d661c1a 100644
--- a/libs/ardour/midi_region.cc
+++ b/libs/ardour/midi_region.cc
@@ -26,17 +26,13 @@
 
 #include <glibmm/thread.h>
 
-#include "pbd/basename.h"
 #include "pbd/xml++.h"
-#include "pbd/enumwriter.h"
 
 #include "ardour/automation_control.h"
-#include "ardour/dB.h"
 #include "ardour/midi_model.h"
 #include "ardour/midi_region.h"
 #include "ardour/midi_ring_buffer.h"
 #include "ardour/midi_source.h"
-#include "ardour/playlist.h"
 #include "ardour/region_factory.h"
 #include "ardour/session.h"
 #include "ardour/tempo.h"
diff --git a/libs/ardour/midi_source.cc b/libs/ardour/midi_source.cc
index 4c854baf69..48d9cdf877 100644
--- a/libs/ardour/midi_source.cc
+++ b/libs/ardour/midi_source.cc
@@ -34,19 +34,18 @@
 #include "pbd/pthread_utils.h"
 #include "pbd/basename.h"
 
-#include "ardour/audioengine.h"
 #include "ardour/debug.h"
 #include "ardour/midi_model.h"
-#include "ardour/midi_ring_buffer.h"
 #include "ardour/midi_state_tracker.h"
 #include "ardour/midi_source.h"
 #include "ardour/session.h"
 #include "ardour/session_directory.h"
 #include "ardour/source_factory.h"
-#include "ardour/tempo.h"
 
 #include "i18n.h"
 
+namespace ARDOUR { template <typename T> class MidiRingBuffer; }
+
 using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
diff --git a/libs/ardour/midi_state_tracker.cc b/libs/ardour/midi_state_tracker.cc
index 7bf23f9358..99a6cd991d 100644
--- a/libs/ardour/midi_state_tracker.cc
+++ b/libs/ardour/midi_state_tracker.cc
@@ -22,9 +22,10 @@
 #include "pbd/compose.h"
 #include "pbd/stacktrace.h"
 
+#include "evoral/EventSink.hpp"
+
 #include "ardour/debug.h"
 #include "ardour/event_type_map.h"
-#include "ardour/midi_ring_buffer.h"
 #include "ardour/midi_source.h"
 #include "ardour/midi_state_tracker.h"
 
diff --git a/libs/ardour/midi_stretch.cc b/libs/ardour/midi_stretch.cc
index 83b845bbfc..aa03def614 100644
--- a/libs/ardour/midi_stretch.cc
+++ b/libs/ardour/midi_stretch.cc
@@ -24,7 +24,6 @@
 #include "ardour/midi_region.h"
 #include "ardour/midi_source.h"
 #include "ardour/midi_stretch.h"
-#include "ardour/session.h"
 #include "ardour/types.h"
 
 #include "i18n.h"
diff --git a/libs/ardour/midi_track.cc b/libs/ardour/midi_track.cc
index 7291a41212..64e61e79f9 100644
--- a/libs/ardour/midi_track.cc
+++ b/libs/ardour/midi_track.cc
@@ -17,35 +17,33 @@
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
-#include "pbd/error.h"
-
 #include "pbd/enumwriter.h"
 #include "pbd/convert.h"
-#include "midi++/events.h"
 #include "evoral/midi_util.h"
 
-#include "ardour/amp.h"
 #include "ardour/buffer_set.h"
 #include "ardour/debug.h"
 #include "ardour/delivery.h"
-#include "ardour/io_processor.h"
 #include "ardour/meter.h"
 #include "ardour/midi_diskstream.h"
 #include "ardour/midi_playlist.h"
 #include "ardour/midi_port.h"
-#include "ardour/midi_region.h"
-#include "ardour/midi_source.h"
 #include "ardour/midi_track.h"
-#include "ardour/panner.h"
 #include "ardour/port.h"
 #include "ardour/processor.h"
-#include "ardour/route_group_specialized.h"
 #include "ardour/session.h"
 #include "ardour/session_playlists.h"
 #include "ardour/utils.h"
 
 #include "i18n.h"
 
+namespace ARDOUR {
+class InterThreadInfo;
+class MidiSource;
+class Region;
+class SMFSource;
+}
+
 using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
diff --git a/libs/ardour/mtc_slave.cc b/libs/ardour/mtc_slave.cc
index 5edb5583f7..6c95730f24 100644
--- a/libs/ardour/mtc_slave.cc
+++ b/libs/ardour/mtc_slave.cc
@@ -23,9 +23,6 @@
 #include <unistd.h>
 
 #include "pbd/error.h"
-#include "pbd/enumwriter.h"
-#include "pbd/failed_constructor.h"
-#include "pbd/pthread_utils.h"
 
 #include "midi++/port.h"
 #include "ardour/debug.h"
diff --git a/libs/ardour/mtdm.cc b/libs/ardour/mtdm.cc
index dceb4f8406..ba73025053 100644
--- a/libs/ardour/mtdm.cc
+++ b/libs/ardour/mtdm.cc
@@ -16,6 +16,8 @@
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
+#include <math.h>
+
 #include "ardour/mtdm.h"
 
 MTDM::MTDM (void)
diff --git a/libs/ardour/panner.cc b/libs/ardour/panner.cc
index 0713e48fe5..6f3aec4646 100644
--- a/libs/ardour/panner.cc
+++ b/libs/ardour/panner.cc
@@ -17,15 +17,10 @@
 
 */
 
-#include "pbd/boost_debug.h"
-
-#include "ardour/audio_buffer.h"
 #include "ardour/buffer_set.h"
 #include "ardour/debug.h"
 #include "ardour/panner.h"
 #include "ardour/pannable.h"
-#include "ardour/session.h"
-#include "ardour/utils.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/panner_shell.cc b/libs/ardour/panner_shell.cc
index fc72a27b09..1aeb94eb7e 100644
--- a/libs/ardour/panner_shell.cc
+++ b/libs/ardour/panner_shell.cc
@@ -43,18 +43,13 @@
 #include "evoral/Curve.hpp"
 
 #include "ardour/audio_buffer.h"
-#include "ardour/audio_buffer.h"
-#include "ardour/automatable.h"
 #include "ardour/buffer_set.h"
 #include "ardour/debug.h"
-#include "ardour/pannable.h"
 #include "ardour/panner.h"
 #include "ardour/panner_manager.h"
 #include "ardour/panner_shell.h"
-#include "ardour/runtime_functions.h"
 #include "ardour/session.h"
 #include "ardour/speakers.h"
-#include "ardour/utils.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/playlist.cc b/libs/ardour/playlist.cc
index 12490d02d7..390f9fdaad 100644
--- a/libs/ardour/playlist.cc
+++ b/libs/ardour/playlist.cc
@@ -19,20 +19,14 @@
 
 #include <stdint.h>
 #include <set>
-#include <fstream>
 #include <algorithm>
-#include <unistd.h>
-#include <cerrno>
 #include <string>
-#include <climits>
 
 #include <boost/lexical_cast.hpp>
 
 #include "pbd/convert.h"
-#include "pbd/failed_constructor.h"
 #include "pbd/stateful_diff_command.h"
 #include "pbd/xml++.h"
-#include "pbd/stacktrace.h"
 
 #include "ardour/debug.h"
 #include "ardour/playlist.h"
diff --git a/libs/ardour/playlist_source.cc b/libs/ardour/playlist_source.cc
index 7583a4e6ea..ed8735b865 100644
--- a/libs/ardour/playlist_source.cc
+++ b/libs/ardour/playlist_source.cc
@@ -33,9 +33,6 @@
 #include "ardour/playlist.h"
 #include "ardour/playlist_source.h"
 #include "ardour/playlist_factory.h"
-#include "ardour/session.h"
-#include "ardour/session_playlists.h"
-#include "ardour/source_factory.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/plugin.cc b/libs/ardour/plugin.cc
index cbcf9f7f7c..4afc39b4ec 100644
--- a/libs/ardour/plugin.cc
+++ b/libs/ardour/plugin.cc
@@ -38,12 +38,16 @@
 #include "pbd/error.h"
 #include "pbd/xml++.h"
 
-#include "ardour/ardour.h"
-#include "ardour/session.h"
-#include "ardour/audioengine.h"
+#include "ardour/buffer_set.h"
+#include "ardour/chan_count.h"
+#include "ardour/chan_mapping.h"
+#include "ardour/data_type.h"
+#include "ardour/midi_buffer.h"
+#include "ardour/midi_state_tracker.h"
 #include "ardour/plugin.h"
-#include "ardour/ladspa_plugin.h"
 #include "ardour/plugin_manager.h"
+#include "ardour/session.h"
+#include "ardour/types.h"
 
 #ifdef AUDIOUNIT_SUPPORT
 #include "ardour/audio_unit.h"
@@ -62,6 +66,8 @@ using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
+namespace ARDOUR { class AudioEngine; }
+
 bool
 PluginInfo::is_instrument () const
 {
diff --git a/libs/ardour/plugin_insert.cc b/libs/ardour/plugin_insert.cc
index 20180b285b..ba61e43e9c 100644
--- a/libs/ardour/plugin_insert.cc
+++ b/libs/ardour/plugin_insert.cc
@@ -35,8 +35,6 @@
 #include "ardour/ladspa_plugin.h"
 #include "ardour/plugin.h"
 #include "ardour/plugin_insert.h"
-#include "ardour/port.h"
-#include "ardour/route.h"
 
 #ifdef LV2_SUPPORT
 #include "ardour/lv2_plugin.h"
@@ -54,7 +52,6 @@
 #include "ardour/audio_unit.h"
 #endif
 
-#include "ardour/audioengine.h"
 #include "ardour/session.h"
 #include "ardour/types.h"
 
diff --git a/libs/ardour/plugin_manager.cc b/libs/ardour/plugin_manager.cc
index 82d5b4748b..a666e7b53e 100644
--- a/libs/ardour/plugin_manager.cc
+++ b/libs/ardour/plugin_manager.cc
@@ -53,7 +53,7 @@
 #include "ardour/ladspa_plugin.h"
 #include "ardour/plugin.h"
 #include "ardour/plugin_manager.h"
-#include "ardour/session.h"
+#include "ardour/rc_configuration.h"
 
 #ifdef LV2_SUPPORT
 #include "ardour/lv2_plugin.h"
diff --git a/libs/ardour/port.cc b/libs/ardour/port.cc
index e9a3c09a10..b0c4b43c06 100644
--- a/libs/ardour/port.cc
+++ b/libs/ardour/port.cc
@@ -21,17 +21,15 @@
 #include "libardour-config.h"
 #endif
 
-#include <stdexcept>
-
 #include <jack/weakjack.h> // so that we can test for new functions at runtime
 
-#include "pbd/error.h"
 #include "pbd/compose.h"
+#include "pbd/error.h"
+#include "pbd/failed_constructor.h"
 
+#include "ardour/audioengine.h"
 #include "ardour/debug.h"
 #include "ardour/port.h"
-#include "ardour/audioengine.h"
-#include "pbd/failed_constructor.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/port_insert.cc b/libs/ardour/port_insert.cc
index cc27c6887f..46c4d7e9d5 100644
--- a/libs/ardour/port_insert.cc
+++ b/libs/ardour/port_insert.cc
@@ -19,19 +19,14 @@
 
 #include <string>
 
-
-#include "pbd/failed_constructor.h"
 #include "pbd/xml++.h"
 
-#include "ardour/audioengine.h"
 #include "ardour/audio_port.h"
-#include "ardour/buffer_set.h"
+#include "ardour/audioengine.h"
 #include "ardour/delivery.h"
+#include "ardour/io.h"
 #include "ardour/mtdm.h"
-#include "ardour/plugin.h"
-#include "ardour/port.h"
 #include "ardour/port_insert.h"
-#include "ardour/route.h"
 #include "ardour/session.h"
 #include "ardour/types.h"
 
diff --git a/libs/ardour/port_set.cc b/libs/ardour/port_set.cc
index 7e9f0656c5..6096e356f5 100644
--- a/libs/ardour/port_set.cc
+++ b/libs/ardour/port_set.cc
@@ -18,9 +18,10 @@
 
 #include <string>
 
-#include "ardour/port_set.h"
-#include "ardour/midi_port.h"
 #include "ardour/audio_port.h"
+#include "ardour/midi_port.h"
+#include "ardour/port.h"
+#include "ardour/port_set.h"
 
 using std::string;
 
diff --git a/libs/ardour/process_thread.cc b/libs/ardour/process_thread.cc
index e910db1c78..55aa692001 100644
--- a/libs/ardour/process_thread.cc
+++ b/libs/ardour/process_thread.cc
@@ -18,7 +18,7 @@
 */
 
 #include <iostream>
-#include "ardour/audioengine.h"
+
 #include "ardour/buffer.h"
 #include "ardour/buffer_manager.h"
 #include "ardour/buffer_set.h"
diff --git a/libs/ardour/processor.cc b/libs/ardour/processor.cc
index 79384c701e..3f8fdf509d 100644
--- a/libs/ardour/processor.cc
+++ b/libs/ardour/processor.cc
@@ -23,20 +23,12 @@
 
 #include <string>
 
-
-#include "pbd/failed_constructor.h"
-#include "pbd/enumwriter.h"
 #include "pbd/xml++.h"
 
+#include "ardour/automatable.h"
+#include "ardour/chan_count.h"
 #include "ardour/processor.h"
-#include "ardour/plugin.h"
-#include "ardour/port.h"
-#include "ardour/route.h"
-#include "ardour/ladspa_plugin.h"
-#include "ardour/buffer_set.h"
-#include "ardour/send.h"
-#include "ardour/port_insert.h"
-#include "ardour/plugin_insert.h"
+#include "ardour/types.h"
 
 #ifdef WINDOWS_VST_SUPPORT
 #include "ardour/windows_vst_plugin.h"
@@ -56,6 +48,8 @@ using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
+namespace ARDOUR { class Session; }
+
 // Always saved as Processor, but may be IOProcessor or Send in legacy sessions
 const string Processor::state_node_name = "Processor";
 
diff --git a/libs/ardour/quantize.cc b/libs/ardour/quantize.cc
index 563b7bf4e7..a4543d773c 100644
--- a/libs/ardour/quantize.cc
+++ b/libs/ardour/quantize.cc
@@ -20,13 +20,8 @@
 
 #include "pbd/basename.h"
 
-#include "ardour/types.h"
 #include "ardour/quantize.h"
-#include "ardour/session.h"
-#include "ardour/smf_source.h"
 #include "ardour/midi_model.h"
-#include "ardour/midi_region.h"
-#include "ardour/tempo.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/rb_effect.cc b/libs/ardour/rb_effect.cc
index d928377e25..7ff60e6912 100644
--- a/libs/ardour/rb_effect.cc
+++ b/libs/ardour/rb_effect.cc
@@ -23,13 +23,13 @@
 #include "pbd/error.h"
 #include "rubberband/RubberBandStretcher.h"
 
-#include "ardour/types.h"
-#include "ardour/stretch.h"
-#include "ardour/pitch.h"
-#include "ardour/audiofilesource.h"
-#include "ardour/session.h"
 #include "ardour/audioregion.h"
+#include "ardour/audiosource.h"
+#include "ardour/pitch.h"
 #include "ardour/progress.h"
+#include "ardour/session.h"
+#include "ardour/stretch.h"
+#include "ardour/types.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/rc_configuration.cc b/libs/ardour/rc_configuration.cc
index 1adde47b2a..d2290c73d5 100644
--- a/libs/ardour/rc_configuration.cc
+++ b/libs/ardour/rc_configuration.cc
@@ -24,18 +24,16 @@
 #include <glib/gstdio.h> /* for g_stat() */
 #include <glibmm/miscutils.h>
 
-#include "pbd/failed_constructor.h"
 #include "pbd/xml++.h"
 #include "pbd/filesystem.h"
 #include "pbd/file_utils.h"
 
 #include "midi++/manager.h"
 
-#include "ardour/ardour.h"
-#include "ardour/rc_configuration.h"
-#include "ardour/audio_diskstream.h"
 #include "ardour/control_protocol_manager.h"
+#include "ardour/diskstream.h"
 #include "ardour/filesystem_paths.h"
+#include "ardour/rc_configuration.h"
 #include "ardour/session_metadata.h"
 
 #include "i18n.h"
diff --git a/libs/ardour/recent_sessions.cc b/libs/ardour/recent_sessions.cc
index 45c30b085b..b1bf49f7ad 100644
--- a/libs/ardour/recent_sessions.cc
+++ b/libs/ardour/recent_sessions.cc
@@ -19,19 +19,14 @@
 
 #include <cstring>
 #include <cerrno>
-#include <unistd.h>
 #include <fstream>
 #include <algorithm>
 
-#include <glibmm/miscutils.h>
-
 #include "pbd/error.h"
 
-#include "ardour/configuration.h"
 #include "ardour/rc_configuration.h"
 #include "ardour/filesystem_paths.h"
 #include "ardour/recent_sessions.h"
-#include "ardour/utils.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index a4a1584792..2166741dda 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -25,11 +25,8 @@
 
 #include <glibmm/thread.h>
 #include "pbd/xml++.h"
-#include "pbd/stacktrace.h"
-#include "pbd/enumwriter.h"
 
 #include "ardour/debug.h"
-#include "ardour/file_source.h"
 #include "ardour/filter.h"
 #include "ardour/playlist.h"
 #include "ardour/playlist_source.h"
@@ -38,9 +35,7 @@
 #include "ardour/region_factory.h"
 #include "ardour/session.h"
 #include "ardour/source.h"
-#include "ardour/source_factory.h"
 #include "ardour/tempo.h"
-#include "ardour/utils.h"
 
 #include "i18n.h"
 
@@ -49,6 +44,7 @@ using namespace ARDOUR;
 using namespace PBD;
 
 namespace ARDOUR {
+	class Progress;
 	namespace Properties {
 		PBD::PropertyDescriptor<bool> muted;
 		PBD::PropertyDescriptor<bool> opaque;
diff --git a/libs/ardour/region_factory.cc b/libs/ardour/region_factory.cc
index 6af256f169..01860048f4 100644
--- a/libs/ardour/region_factory.cc
+++ b/libs/ardour/region_factory.cc
@@ -20,17 +20,14 @@
 #include <inttypes.h>
 
 #include "pbd/error.h"
-#include "pbd/boost_debug.h"
 
-#include "ardour/session.h"
-
-#include "ardour/region_factory.h"
-#include "ardour/region.h"
 #include "ardour/audioregion.h"
 #include "ardour/audiosource.h"
-#include "ardour/midi_source.h"
 #include "ardour/midi_region.h"
-#include "ardour/utils.h"
+#include "ardour/midi_source.h"
+#include "ardour/region.h"
+#include "ardour/region_factory.h"
+#include "ardour/session.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/return.cc b/libs/ardour/return.cc
index 0152155338..43a2e1bfd1 100644
--- a/libs/ardour/return.cc
+++ b/libs/ardour/return.cc
@@ -22,16 +22,12 @@
 #include "pbd/xml++.h"
 
 #include "ardour/amp.h"
-#include "ardour/audio_port.h"
+#include "ardour/audioengine.h"
 #include "ardour/buffer_set.h"
 #include "ardour/io.h"
 #include "ardour/meter.h"
-#include "ardour/panner.h"
-#include "ardour/port.h"
 #include "ardour/return.h"
 #include "ardour/session.h"
-#include "ardour/mute_master.h"
-#include "ardour/audioengine.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/reverse.cc b/libs/ardour/reverse.cc
index 45d7c83051..06fafb0ca4 100644
--- a/libs/ardour/reverse.cc
+++ b/libs/ardour/reverse.cc
@@ -19,19 +19,16 @@
 
 #include <algorithm>
 
-#include "pbd/basename.h"
-
-#include "ardour/types.h"
-#include "ardour/reverse.h"
-#include "ardour/audiofilesource.h"
-#include "ardour/session.h"
 #include "ardour/audioregion.h"
-
-#include "i18n.h"
+#include "ardour/audiosource.h"
+#include "ardour/reverse.h"
+#include "ardour/types.h"
 
 using namespace std;
 using namespace ARDOUR;
 
+namespace ARDOUR { class Progress; class Session; }
+
 Reverse::Reverse (Session& s)
 	: Filter (s)
 {
diff --git a/libs/ardour/route.cc b/libs/ardour/route.cc
index 3f68e266eb..1948ba14aa 100644
--- a/libs/ardour/route.cc
+++ b/libs/ardour/route.cc
@@ -33,40 +33,30 @@
 #include "pbd/convert.h"
 #include "pbd/boost_debug.h"
 
-#include "evoral/Curve.hpp"
-
 #include "ardour/amp.h"
-#include "ardour/audio_port.h"
+#include "ardour/audio_buffer.h"
 #include "ardour/audioengine.h"
 #include "ardour/buffer.h"
 #include "ardour/buffer_set.h"
-#include "ardour/configuration.h"
-#include "ardour/cycle_timer.h"
+#include "ardour/capturing_processor.h"
 #include "ardour/debug.h"
 #include "ardour/delivery.h"
-#include "ardour/dB.h"
-#include "ardour/internal_send.h"
 #include "ardour/internal_return.h"
-#include "ardour/ladspa_plugin.h"
+#include "ardour/internal_send.h"
 #include "ardour/meter.h"
-#include "ardour/mix.h"
 #include "ardour/monitor_processor.h"
 #include "ardour/pannable.h"
-#include "ardour/panner.h"
 #include "ardour/panner_shell.h"
 #include "ardour/plugin_insert.h"
 #include "ardour/port.h"
 #include "ardour/port_insert.h"
 #include "ardour/processor.h"
-#include "ardour/profile.h"
 #include "ardour/route.h"
 #include "ardour/route_group.h"
 #include "ardour/send.h"
 #include "ardour/session.h"
-#include "ardour/timestamps.h"
-#include "ardour/utils.h"
 #include "ardour/unknown_processor.h"
-#include "ardour/capturing_processor.h"
+#include "ardour/utils.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/route_group.cc b/libs/ardour/route_group.cc
index ef7645e63f..cb00df724a 100644
--- a/libs/ardour/route_group.cc
+++ b/libs/ardour/route_group.cc
@@ -21,17 +21,14 @@
 
 #include <algorithm>
 
-
 #include "pbd/error.h"
 #include "pbd/enumwriter.h"
 #include "pbd/strsplit.h"
 
 #include "ardour/amp.h"
-#include "ardour/debug.h"
-#include "ardour/route_group.h"
 #include "ardour/audio_track.h"
-#include "ardour/audio_diskstream.h"
-#include "ardour/configuration.h"
+#include "ardour/route.h"
+#include "ardour/route_group.h"
 #include "ardour/session.h"
 
 #include "i18n.h"
diff --git a/libs/ardour/route_group_member.cc b/libs/ardour/route_group_member.cc
index 9e2682bbb9..85d2f981d7 100644
--- a/libs/ardour/route_group_member.cc
+++ b/libs/ardour/route_group_member.cc
@@ -14,15 +14,14 @@
     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-
 */
 
-
-#include "ardour/route_group.h"
 #include "ardour/route_group_member.h"
 
 using namespace ARDOUR;
 
+namespace ARDOUR { class RouteGroup; }
+
 /** Set the route group; it can be set to 0 for `none' */
 void
 RouteGroupMember::set_route_group (RouteGroup *rg)
diff --git a/libs/ardour/send.cc b/libs/ardour/send.cc
index 819165b352..677b8c2e3b 100644
--- a/libs/ardour/send.cc
+++ b/libs/ardour/send.cc
@@ -26,15 +26,18 @@
 #include "ardour/amp.h"
 #include "ardour/send.h"
 #include "ardour/session.h"
-#include "ardour/port.h"
-#include "ardour/audio_port.h"
 #include "ardour/buffer_set.h"
 #include "ardour/meter.h"
-#include "ardour/panner.h"
 #include "ardour/io.h"
 
 #include "i18n.h"
 
+namespace ARDOUR {
+class AutomationControl;
+class MuteMaster;
+class Pannable;
+}
+
 using namespace ARDOUR;
 using namespace PBD;
 using namespace std;
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 1192e898f6..b09d67fb35 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -56,54 +56,38 @@
 #include "ardour/audio_track.h"
 #include "ardour/audioengine.h"
 #include "ardour/audiofilesource.h"
-#include "ardour/audioplaylist.h"
-#include "ardour/audioregion.h"
 #include "ardour/auditioner.h"
 #include "ardour/buffer_manager.h"
 #include "ardour/buffer_set.h"
 #include "ardour/bundle.h"
 #include "ardour/butler.h"
 #include "ardour/click.h"
-#include "ardour/configuration.h"
 #include "ardour/control_protocol_manager.h"
-#include "ardour/cycle_timer.h"
 #include "ardour/data_type.h"
 #include "ardour/debug.h"
 #include "ardour/filename_extensions.h"
-#include "ardour/internal_send.h"
-#include "ardour/io_processor.h"
-#include "ardour/midi_diskstream.h"
-#include "ardour/midi_playlist.h"
-#include "ardour/midi_region.h"
+#include "ardour/graph.h"
 #include "ardour/midi_track.h"
 #include "ardour/midi_ui.h"
 #include "ardour/named_selection.h"
-#include "ardour/process_thread.h"
+#include "ardour/operations.h"
 #include "ardour/playlist.h"
 #include "ardour/plugin.h"
 #include "ardour/plugin_insert.h"
-#include "ardour/port_insert.h"
-#include "ardour/processor.h"
+#include "ardour/process_thread.h"
 #include "ardour/rc_configuration.h"
 #include "ardour/recent_sessions.h"
+#include "ardour/region.h"
 #include "ardour/region_factory.h"
-#include "ardour/return.h"
 #include "ardour/route_graph.h"
 #include "ardour/route_group.h"
 #include "ardour/send.h"
 #include "ardour/session.h"
 #include "ardour/session_directory.h"
-#include "ardour/session_directory.h"
 #include "ardour/session_playlists.h"
-#include "ardour/slave.h"
 #include "ardour/smf_source.h"
 #include "ardour/source_factory.h"
-#include "ardour/tape_file_matcher.h"
-#include "ardour/tempo.h"
 #include "ardour/utils.h"
-#include "ardour/graph.h"
-#include "ardour/speakers.h"
-#include "ardour/operations.h"
 
 #include "midi++/port.h"
 #include "midi++/jack_midi_port.h"
@@ -112,6 +96,12 @@
 
 #include "i18n.h"
 
+namespace ARDOUR {
+class MidiSource;
+class Processor;
+class Speakers;
+}
+
 using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
diff --git a/libs/ardour/session_butler.cc b/libs/ardour/session_butler.cc
index 87e3c34fb5..88f61335e0 100644
--- a/libs/ardour/session_butler.cc
+++ b/libs/ardour/session_butler.cc
@@ -31,15 +31,12 @@
 #include "pbd/pthread_utils.h"
 #include "pbd/stacktrace.h"
 
-#include "ardour/audio_diskstream.h"
-#include "ardour/audioengine.h"
 #include "ardour/butler.h"
-#include "ardour/configuration.h"
-#include "ardour/io.h"
-#include "ardour/midi_diskstream.h"
+#include "ardour/route.h"
 #include "ardour/session.h"
-#include "ardour/timestamps.h"
+#include "ardour/session_event.h"
 #include "ardour/track.h"
+#include "ardour/types.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/session_click.cc b/libs/ardour/session_click.cc
index e36c871fae..abfbaecfcd 100644
--- a/libs/ardour/session_click.cc
+++ b/libs/ardour/session_click.cc
@@ -21,13 +21,13 @@
 #include <cerrno>
 
 #include "ardour/amp.h"
-#include "ardour/ardour.h"
 #include "ardour/audio_buffer.h"
 #include "ardour/buffer_set.h"
 #include "ardour/click.h"
 #include "ardour/io.h"
 #include "ardour/session.h"
 #include "ardour/tempo.h"
+#include "ardour/types.h"
 
 #include <sndfile.h>
 
diff --git a/libs/ardour/session_command.cc b/libs/ardour/session_command.cc
index 68aba1a689..0246f55479 100644
--- a/libs/ardour/session_command.cc
+++ b/libs/ardour/session_command.cc
@@ -17,29 +17,28 @@
 
 */
 
-#include "ardour/session.h"
-#include "ardour/route.h"
-#include "pbd/memento_command.h"
-#include "ardour/diskstream.h"
-#include "ardour/playlist.h"
-#include "ardour/audioplaylist.h"
-#include "ardour/audio_track.h"
-#include "ardour/midi_playlist.h"
-#include "ardour/midi_track.h"
-#include "ardour/tempo.h"
-#include "ardour/audiosource.h"
-#include "ardour/audioregion.h"
-#include "ardour/midi_source.h"
-#include "ardour/midi_region.h"
-#include "ardour/session_playlists.h"
-#include "ardour/region_factory.h"
+#include <string>
+
+#include "ardour/automation_list.h"
+#include "ardour/location.h"
 #include "ardour/midi_automation_list_binder.h"
-#include "pbd/error.h"
-#include "pbd/id.h"
-#include "pbd/statefuldestructible.h"
-#include "pbd/failed_constructor.h"
-#include "pbd/stateful_diff_command.h"
+#include "ardour/playlist.h"
+#include "ardour/region.h"
+#include "ardour/region_factory.h"
+#include "ardour/route.h"
+#include "ardour/session.h"
+#include "ardour/session_playlists.h"
+#include "ardour/source.h"
+#include "ardour/tempo.h"
 #include "evoral/Curve.hpp"
+#include "pbd/error.h"
+#include "pbd/failed_constructor.h"
+#include "pbd/id.h"
+#include "pbd/memento_command.h"
+#include "pbd/stateful_diff_command.h"
+#include "pbd/statefuldestructible.h"
+
+class Command;
 
 using namespace PBD;
 using namespace ARDOUR;
@@ -90,7 +89,7 @@ Session::memento_command_factory(XMLNode *n)
     }
 
     /* create command */
-    string obj_T = n->property ("type-name")->value();
+    std::string obj_T = n->property ("type-name")->value();
 
     if (obj_T == "ARDOUR::AudioRegion" || obj_T == "ARDOUR::MidiRegion" || obj_T == "ARDOUR::Region") {
 	    boost::shared_ptr<Region> r = RegionFactory::region_by_id (id);
@@ -139,7 +138,7 @@ Session::memento_command_factory(XMLNode *n)
 			    );
 	    }
 
-	    cerr << "Alist " << id << " not found\n";
+	    std::cerr << "Alist " << id << " not found\n";
 
     } else if (registry.count(id)) { // For Editor and AutomationLine which are off-limits herea
 	    return new MementoCommand<PBD::StatefulDestructible>(*registry[id], before, after);
@@ -156,7 +155,7 @@ Session::stateful_diff_command_factory (XMLNode* n)
 {
 	PBD::ID const id (n->property("obj-id")->value ());
 
-	string const obj_T = n->property ("type-name")->value ();
+	std::string const obj_T = n->property ("type-name")->value ();
 	if ((obj_T == "ARDOUR::AudioRegion" || obj_T == "ARDOUR::MidiRegion")) {
 		boost::shared_ptr<Region> r = RegionFactory::region_by_id (id);
 		if (r) {
@@ -164,13 +163,13 @@ Session::stateful_diff_command_factory (XMLNode* n)
 		}
 
 	} else if (obj_T == "ARDOUR::AudioPlaylist" ||  obj_T == "ARDOUR::MidiPlaylist") {
-                boost::shared_ptr<Playlist> p = playlists->by_id (id);
-                if (p) {
-                        return new StatefulDiffCommand (p, *n);
-                } else {
-                        cerr << "Playlist with ID = " << id << " not found\n";
-                }
-        }
+		boost::shared_ptr<Playlist> p = playlists->by_id (id);
+		if (p) {
+			return new StatefulDiffCommand (p, *n);
+		} else {
+			std::cerr << "Playlist with ID = " << id << " not found\n";
+		}
+	}
 
 	/* we failed */
 
diff --git a/libs/ardour/session_configuration.cc b/libs/ardour/session_configuration.cc
index 899b85e770..cfb6fb8668 100644
--- a/libs/ardour/session_configuration.cc
+++ b/libs/ardour/session_configuration.cc
@@ -20,7 +20,6 @@
 #include "ardour/types.h"
 #include "ardour/utils.h"
 #include "ardour/session_configuration.h"
-#include "ardour/ardour.h"
 #include "i18n.h"
 
 using namespace ARDOUR;
diff --git a/libs/ardour/session_events.cc b/libs/ardour/session_events.cc
index 421c81d42c..84b1b75b12 100644
--- a/libs/ardour/session_events.cc
+++ b/libs/ardour/session_events.cc
@@ -20,15 +20,10 @@
 #include <cmath>
 #include <unistd.h>
 
-#include "ardour/timestamps.h"
-
 #include "pbd/error.h"
 #include "pbd/enumwriter.h"
 #include "pbd/stacktrace.h"
 
-#include "ardour/ardour.h"
-#include "ardour/audio_diskstream.h"
-#include "ardour/butler.h"
 #include "ardour/debug.h"
 #include "ardour/session_event.h"
 
diff --git a/libs/ardour/session_export.cc b/libs/ardour/session_export.cc
index 4d2944aad5..1d11dccbd0 100644
--- a/libs/ardour/session_export.cc
+++ b/libs/ardour/session_export.cc
@@ -26,12 +26,11 @@
 
 #include "ardour/audioengine.h"
 #include "ardour/butler.h"
-#include "ardour/export_failed.h"
 #include "ardour/export_handler.h"
 #include "ardour/export_status.h"
+#include "ardour/process_thread.h"
 #include "ardour/session.h"
 #include "ardour/track.h"
-#include "ardour/process_thread.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/session_midi.cc b/libs/ardour/session_midi.cc
index 8b9da721f2..caceebf853 100644
--- a/libs/ardour/session_midi.cc
+++ b/libs/ardour/session_midi.cc
@@ -38,16 +38,13 @@
 
 #include "timecode/time.h"
 
-#include "ardour/configuration.h"
-#include "ardour/debug.h"
-#include "ardour/audioengine.h"
-#include "ardour/session.h"
 #include "ardour/audio_track.h"
+#include "ardour/audioengine.h"
+#include "ardour/debug.h"
 #include "ardour/midi_track.h"
 #include "ardour/midi_ui.h"
-#include "ardour/audio_diskstream.h"
+#include "ardour/session.h"
 #include "ardour/slave.h"
-#include "ardour/cycles.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/session_object.cc b/libs/ardour/session_object.cc
index 5ff28b59d0..39b31550d9 100644
--- a/libs/ardour/session_object.cc
+++ b/libs/ardour/session_object.cc
@@ -18,8 +18,9 @@
 */
 
 #include <iostream>
-#include "ardour/session_object.h"
+
 #include "ardour/debug.h"
+#include "ardour/session_object.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/session_playlists.cc b/libs/ardour/session_playlists.cc
index 8e25cbfd9d..b833aea1f2 100644
--- a/libs/ardour/session_playlists.cc
+++ b/libs/ardour/session_playlists.cc
@@ -18,17 +18,14 @@
 */
 #include <vector>
 
-#include "pbd/xml++.h"
-#include "pbd/compose.h"
 #include "ardour/debug.h"
-#include "ardour/session_playlists.h"
 #include "ardour/playlist.h"
-#include "ardour/region.h"
 #include "ardour/playlist_factory.h"
-#include "ardour/session.h"
-#include "ardour/source.h"
+#include "ardour/session_playlists.h"
 #include "ardour/track.h"
 #include "i18n.h"
+#include "pbd/compose.h"
+#include "pbd/xml++.h"
 
 using namespace std;
 using namespace PBD;
diff --git a/libs/ardour/session_process.cc b/libs/ardour/session_process.cc
index c002cc9008..29ce370d7f 100644
--- a/libs/ardour/session_process.cc
+++ b/libs/ardour/session_process.cc
@@ -27,20 +27,18 @@
 
 #include <glibmm/thread.h>
 
-#include "ardour/ardour.h"
 #include "ardour/audioengine.h"
 #include "ardour/auditioner.h"
 #include "ardour/butler.h"
+#include "ardour/cycle_timer.h"
 #include "ardour/debug.h"
+#include "ardour/graph.h"
+#include "ardour/port.h"
 #include "ardour/process_thread.h"
 #include "ardour/session.h"
 #include "ardour/slave.h"
-#include "ardour/timestamps.h"
-#include "ardour/graph.h"
-#include "ardour/audio_port.h"
-#include "ardour/tempo.h"
 #include "ardour/ticker.h"
-#include "ardour/cycle_timer.h"
+#include "ardour/types.h"
 
 #include "midi++/manager.h"
 #include "midi++/mmc.h"
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index c21b492c8f..4b40a80d80 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -57,6 +57,8 @@
 #include "midi++/port.h"
 #include "midi++/manager.h"
 
+#include "evoral/SMF.hpp"
+
 #include "pbd/boost_debug.h"
 #include "pbd/basename.h"
 #include "pbd/controllable_descriptor.h"
@@ -71,34 +73,26 @@
 
 #include "ardour/amp.h"
 #include "ardour/audio_diskstream.h"
-#include "ardour/audio_playlist_source.h"
 #include "ardour/audio_track.h"
 #include "ardour/audioengine.h"
 #include "ardour/audiofilesource.h"
-#include "ardour/audioplaylist.h"
 #include "ardour/audioregion.h"
-#include "ardour/auditioner.h"
 #include "ardour/automation_control.h"
-#include "ardour/buffer.h"
 #include "ardour/butler.h"
-#include "ardour/configuration.h"
 #include "ardour/control_protocol_manager.h"
-#include "ardour/cycle_timer.h"
 #include "ardour/directory_names.h"
 #include "ardour/filename_extensions.h"
-#include "ardour/io_processor.h"
 #include "ardour/location.h"
-#include "ardour/midi_diskstream.h"
 #include "ardour/midi_model.h"
 #include "ardour/midi_patch_manager.h"
-#include "ardour/midi_playlist.h"
 #include "ardour/midi_region.h"
 #include "ardour/midi_source.h"
 #include "ardour/midi_track.h"
 #include "ardour/named_selection.h"
 #include "ardour/pannable.h"
-#include "ardour/processor.h"
+#include "ardour/playlist_factory.h"
 #include "ardour/port.h"
+#include "ardour/processor.h"
 #include "ardour/proxy_controllable.h"
 #include "ardour/recent_sessions.h"
 #include "ardour/region_factory.h"
@@ -107,13 +101,10 @@
 #include "ardour/session.h"
 #include "ardour/session_directory.h"
 #include "ardour/session_metadata.h"
-#include "ardour/session_state_utils.h"
 #include "ardour/session_playlists.h"
+#include "ardour/session_state_utils.h"
 #include "ardour/session_utils.h"
 #include "ardour/silentfilesource.h"
-#include "ardour/slave.h"
-#include "ardour/smf_source.h"
-#include "ardour/sndfile_helpers.h"
 #include "ardour/sndfilesource.h"
 #include "ardour/source_factory.h"
 #include "ardour/speakers.h"
@@ -121,10 +112,6 @@
 #include "ardour/tempo.h"
 #include "ardour/ticker.h"
 #include "ardour/user_bundle.h"
-#include "ardour/utils.h"
-#include "ardour/utils.h"
-#include "ardour/version.h"
-#include "ardour/playlist_factory.h"
 
 #include "control_protocol/control_protocol.h"
 
@@ -782,7 +769,7 @@ Session::save_state (string snapshot_name, bool pending, bool switch_to_snapshot
 		} catch (Evoral::SMF::FileError& e) {
 			error << string_compose ("Could not write to MIDI file %1; MIDI data not saved.", e.file_name ()) << endmsg;
 		}
-        }
+	}
 
 	tree.set_root (&get_state());
 
diff --git a/libs/ardour/session_time.cc b/libs/ardour/session_time.cc
index eef05e879a..42ae315597 100644
--- a/libs/ardour/session_time.cc
+++ b/libs/ardour/session_time.cc
@@ -32,9 +32,6 @@
 #include "pbd/enumwriter.h"
 #include "pbd/stacktrace.h"
 
-#include "ardour/ardour.h"
-#include "ardour/configuration.h"
-#include "ardour/audioengine.h"
 #include "ardour/session.h"
 #include "ardour/tempo.h"
 
diff --git a/libs/ardour/session_transport.cc b/libs/ardour/session_transport.cc
index ffcb7e8d24..5fef402d9f 100644
--- a/libs/ardour/session_transport.cc
+++ b/libs/ardour/session_transport.cc
@@ -17,14 +17,13 @@
 
 */
 
-#include <cmath>
-#include <cerrno>
-#include <unistd.h>
-
 #ifdef WAF_BUILD
 #include "libardour-config.h"
 #endif
 
+#include <cmath>
+#include <cerrno>
+#include <unistd.h>
 
 #include "pbd/undo.h"
 #include "pbd/error.h"
@@ -36,7 +35,6 @@
 #include "midi++/port.h"
 #include "midi++/manager.h"
 
-#include "ardour/ardour.h"
 #include "ardour/audioengine.h"
 #include "ardour/auditioner.h"
 #include "ardour/butler.h"
diff --git a/libs/ardour/smf_source.cc b/libs/ardour/smf_source.cc
index 52377ee915..1fd058dbd8 100644
--- a/libs/ardour/smf_source.cc
+++ b/libs/ardour/smf_source.cc
@@ -34,7 +34,6 @@
 
 #include "evoral/Control.hpp"
 
-#include "ardour/audioengine.h"
 #include "ardour/event_type_map.h"
 #include "ardour/midi_model.h"
 #include "ardour/midi_ring_buffer.h"
diff --git a/libs/ardour/sndfile_helpers.cc b/libs/ardour/sndfile_helpers.cc
index 07281e6901..459890e829 100644
--- a/libs/ardour/sndfile_helpers.cc
+++ b/libs/ardour/sndfile_helpers.cc
@@ -19,9 +19,6 @@
 
 #include <strings.h>
 #include <map>
-#include <vector>
-
-#include "pbd/convert.h"
 
 #include <sndfile.h>
 #include "ardour/sndfile_helpers.h"
diff --git a/libs/ardour/sndfilesource.cc b/libs/ardour/sndfilesource.cc
index f3f37fa2a1..0ec318a0ac 100644
--- a/libs/ardour/sndfilesource.cc
+++ b/libs/ardour/sndfilesource.cc
@@ -35,8 +35,6 @@
 #include "ardour/sndfilesource.h"
 #include "ardour/sndfile_helpers.h"
 #include "ardour/utils.h"
-#include "ardour/version.h"
-#include "ardour/rc_configuration.h"
 #include "ardour/session.h"
 
 #include "i18n.h"
diff --git a/libs/ardour/strip_silence.cc b/libs/ardour/strip_silence.cc
index a5b115205a..3839b984bd 100644
--- a/libs/ardour/strip_silence.cc
+++ b/libs/ardour/strip_silence.cc
@@ -22,8 +22,6 @@
 #include "ardour/strip_silence.h"
 #include "ardour/audioregion.h"
 #include "ardour/region_factory.h"
-#include "ardour/session.h"
-#include "ardour/dB.h"
 #include "ardour/progress.h"
 
 using namespace ARDOUR;
diff --git a/libs/ardour/tempo.cc b/libs/ardour/tempo.cc
index 798ced17b4..e64a116933 100644
--- a/libs/ardour/tempo.cc
+++ b/libs/ardour/tempo.cc
@@ -28,7 +28,6 @@
 #include "evoral/types.hpp"
 #include "ardour/debug.h"
 #include "ardour/tempo.h"
-#include "ardour/utils.h"
 
 #include "i18n.h"
 #include <locale.h>
diff --git a/libs/ardour/tempo_map_importer.cc b/libs/ardour/tempo_map_importer.cc
index b170aea8ea..f0447b2f82 100644
--- a/libs/ardour/tempo_map_importer.cc
+++ b/libs/ardour/tempo_map_importer.cc
@@ -23,9 +23,8 @@
 #include <sstream>
 
 #include "ardour/session.h"
+#include "ardour/tempo.h"
 #include "pbd/failed_constructor.h"
-#include "pbd/compose.h"
-#include "pbd/error.h"
 
 #include "i18n.h"
 
diff --git a/libs/ardour/track.cc b/libs/ardour/track.cc
index c2750ccf98..9699558ff1 100644
--- a/libs/ardour/track.cc
+++ b/libs/ardour/track.cc
@@ -18,14 +18,12 @@
 #include "pbd/error.h"
 
 #include "ardour/amp.h"
-#include "ardour/audioplaylist.h"
-#include "ardour/audioregion.h"
-#include "ardour/audiosource.h"
 #include "ardour/debug.h"
 #include "ardour/delivery.h"
 #include "ardour/diskstream.h"
 #include "ardour/io_processor.h"
 #include "ardour/meter.h"
+#include "ardour/playlist.h"
 #include "ardour/port.h"
 #include "ardour/processor.h"
 #include "ardour/route_group_specialized.h"
diff --git a/libs/ardour/user_bundle.cc b/libs/ardour/user_bundle.cc
index b6c38e0eed..de71a87d86 100644
--- a/libs/ardour/user_bundle.cc
+++ b/libs/ardour/user_bundle.cc
@@ -1,13 +1,9 @@
-#include <cassert>
-#include "pbd/failed_constructor.h"
-#include "pbd/compose.h"
-#include "pbd/xml++.h"
 #include "ardour/user_bundle.h"
-#include "ardour/port_set.h"
-#include "ardour/io.h"
-#include "ardour/session.h"
-#include "ardour/audioengine.h"
 #include "i18n.h"
+#include "pbd/compose.h"
+#include "pbd/error.h"
+#include "pbd/failed_constructor.h"
+#include "pbd/xml++.h"
 
 ARDOUR::UserBundle::UserBundle (std::string const & n)
 	: Bundle (n)
diff --git a/libs/midi++2/midi++/names.h b/libs/midi++2/midi++/names.h
index 9597de3928..1a94e675e3 100644
--- a/libs/midi++2/midi++/names.h
+++ b/libs/midi++2/midi++/names.h
@@ -20,8 +20,9 @@
 #ifndef __midinames_h__
 #define __midinames_h__
 
-#include "events.h"
+#include <stdint.h>
 
+#include "events.h"
 
 /** \group midi
  */