diff --git a/libs/ardour/ardour/location.h b/libs/ardour/ardour/location.h
index f3af8744b8..e308cae6b5 100644
--- a/libs/ardour/ardour/location.h
+++ b/libs/ardour/ardour/location.h
@@ -38,6 +38,8 @@
 #include "pbd/stateful.h"
 #include "pbd/statefuldestructible.h"
 
+#include "temporal/types.h"
+
 #include "ardour/ardour.h"
 #include "ardour/scene_change.h"
 #include "ardour/session_handle.h"
@@ -169,6 +171,8 @@ public:
 	Temporal::TimeDomain position_time_domain() const { return _start.time_domain(); }
 	void set_position_time_domain (Temporal::TimeDomain ps);
 
+	void globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
+
 	class ChangeSuspender {
 		public:
 			ChangeSuspender (Location* l) : _l (l) {
@@ -292,6 +296,8 @@ public:
 
 	void find_all_between (timepos_t const & start, timepos_t const & end, LocationList&, Location::Flags);
 
+	void globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
+
 	PBD::Signal1<void,Location*> current_changed;
 
 	/* Objects that care about individual addition and removal of Locations should connect to added/removed.
diff --git a/libs/ardour/ardour/playlist.h b/libs/ardour/ardour/playlist.h
index cbfbb6a8f7..cd92ed2bc1 100644
--- a/libs/ardour/ardour/playlist.h
+++ b/libs/ardour/ardour/playlist.h
@@ -302,6 +302,8 @@ public:
 
 	void set_capture_insertion_in_progress (bool yn);
 
+	void globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
+
 protected:
 	friend class Session;
 
diff --git a/libs/ardour/ardour/route.h b/libs/ardour/ardour/route.h
index a0663cab5b..7f8155b823 100644
--- a/libs/ardour/ardour/route.h
+++ b/libs/ardour/ardour/route.h
@@ -41,6 +41,8 @@
 #include "pbd/controllable.h"
 #include "pbd/destructible.h"
 
+#include "temporal/types.h"
+
 #include "ardour/ardour.h"
 #include "ardour/gain_control.h"
 #include "ardour/instrument_info.h"
@@ -615,6 +617,8 @@ public:
 
 	virtual void use_captured_sources (SourceList& srcs, CaptureInfos const &) {}
 
+	void globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
+
 protected:
 	friend class Session;
 
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index cbf4588b25..797ea6a358 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -2374,6 +2374,8 @@ private:
 
 	int tb_with_filled_slots;
 	void handle_slots_empty_status (std::weak_ptr<Route> const &);
+
+	void globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
 };
 
 
diff --git a/libs/ardour/ardour/session_playlists.h b/libs/ardour/ardour/session_playlists.h
index ccfbae9487..84225eed4d 100644
--- a/libs/ardour/ardour/session_playlists.h
+++ b/libs/ardour/ardour/session_playlists.h
@@ -70,6 +70,8 @@ public:
 	std::vector<std::shared_ptr<Playlist> > get_unused () const;
 	uint32_t n_playlists() const;
 
+	void globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
+
 private:
 	friend class Session;
 
diff --git a/libs/ardour/location.cc b/libs/ardour/location.cc
index a58734a602..9227a086b4 100644
--- a/libs/ardour/location.cc
+++ b/libs/ardour/location.cc
@@ -763,6 +763,11 @@ Location::set_scene_change (std::shared_ptr<SceneChange>  sc)
 	}
 }
 
+void
+Location::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
+{
+}
+
 /*---------------------------------------------------------------------- */
 
 Locations::Locations (Session& s)
@@ -1716,3 +1721,13 @@ Locations::clear_cue_markers (samplepos_t start, samplepos_t end)
 
 	return removed_at_least_one;
 }
+
+void
+Locations::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
+{
+	Glib::Threads::RWLock::WriterLock lm (_lock);
+	for (auto & l : locations) {
+		globally_change_time_domain (from, to);
+	}
+
+}
diff --git a/libs/ardour/playlist.cc b/libs/ardour/playlist.cc
index 30bde66ac0..f7c3606e32 100644
--- a/libs/ardour/playlist.cc
+++ b/libs/ardour/playlist.cc
@@ -3506,3 +3506,8 @@ Playlist::time_domain() const
 
 	return Temporal::BeatTime;
 }
+
+void
+Playlist::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
+{
+}
diff --git a/libs/ardour/route.cc b/libs/ardour/route.cc
index f617a08677..fe2a0d2b34 100644
--- a/libs/ardour/route.cc
+++ b/libs/ardour/route.cc
@@ -6355,3 +6355,8 @@ Route::tempo_map_changed ()
 		_triggerbox->tempo_map_changed ();
 	}
 }
+
+void
+Route::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
+{
+}
diff --git a/libs/ardour/session_playlists.cc b/libs/ardour/session_playlists.cc
index 272de7695d..8398b65fc2 100644
--- a/libs/ardour/session_playlists.cc
+++ b/libs/ardour/session_playlists.cc
@@ -684,3 +684,13 @@ SessionPlaylists::foreach (boost::function<void(std::shared_ptr<const Playlist>)
 		}
 	}
 }
+
+void
+SessionPlaylists::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
+{
+	Glib::Threads::Mutex::Lock lm (lock);
+
+	for (auto & pl : playlists) {
+		pl->globally_change_time_domain (from, to);
+	}
+}
diff --git a/libs/ardour/session_time.cc b/libs/ardour/session_time.cc
index 3501bb6b84..f84f922004 100644
--- a/libs/ardour/session_time.cc
+++ b/libs/ardour/session_time.cc
@@ -32,7 +32,9 @@
 #include "pbd/error.h"
 #include "pbd/enumwriter.h"
 
+#include "ardour/location.h"
 #include "ardour/session.h"
+#include "ardour/session_playlists.h"
 #include "ardour/tempo.h"
 #include "ardour/transport_fsm.h"
 
@@ -296,3 +298,18 @@ Session::any_duration_to_samples (samplepos_t position, AnyTime const & duration
 
 	return duration.samples;
 }
+
+void
+Session::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
+{
+	{
+		std::shared_ptr<RouteList> rl (routes.reader());
+
+		for (auto & r : *rl) {
+			r->globally_change_time_domain (from, to);
+		}
+	}
+
+	_playlists->globally_change_time_domain (from, to);
+	_locations->globally_change_time_domain (from, to);
+}