diff --git a/libs/ardour/ardour/audio_unit.h b/libs/ardour/ardour/audio_unit.h
index cabc78842e..7914dce0ab 100644
--- a/libs/ardour/ardour/audio_unit.h
+++ b/libs/ardour/ardour/audio_unit.h
@@ -170,10 +170,7 @@ class LIBARDOUR_API AUPlugin : public ARDOUR::Plugin
 	int32_t input_channels;
 	int32_t output_channels;
 	std::vector<std::pair<int,int> > io_configs;
-	pframes_t _current_block_size;
 	framecnt_t _last_nframes;
-	framepos_t _transport_frame;
-	framepos_t _transport_speed;
 	bool _requires_fixed_size_buffers;
 	AudioBufferList* buffers;
 	bool _has_midi_input;
diff --git a/libs/ardour/audio_unit.cc b/libs/ardour/audio_unit.cc
index 88cc197d60..74b7ce6566 100644
--- a/libs/ardour/audio_unit.cc
+++ b/libs/ardour/audio_unit.cc
@@ -430,7 +430,8 @@ AUPlugin::AUPlugin (AudioEngine& engine, Session& session, boost::shared_ptr<CAC
 	, comp (_comp)
 	, unit (new CAAudioUnit)
 	, initialized (false)
-	, _current_block_size (0)
+	, _last_nframes (0)
+	, _current_latency (-1)
 	, _requires_fixed_size_buffers (false)
 	, buffers (0)
 	, variable_inputs (false)
@@ -448,8 +449,8 @@ AUPlugin::AUPlugin (AudioEngine& engine, Session& session, boost::shared_ptr<CAC
 	, audio_input_cnt (0)
 	, _parameter_listener (0)
 	, _parameter_listener_arg (0)
-	, transport_frame (false)
-	, transport_speed (false)
+	, transport_frame (0)
+	, transport_speed (0)
 	, last_transport_speed (0.0)
 {
 	if (!preset_search_path_initialized) {
@@ -470,8 +471,8 @@ AUPlugin::AUPlugin (const AUPlugin& other)
 	, comp (other.get_comp())
 	, unit (new CAAudioUnit)
 	, initialized (false)
-	, _current_block_size (0)
 	, _last_nframes (0)
+	, _current_latency (-1)
 	, _requires_fixed_size_buffers (false)
 	, buffers (0)
 	, variable_inputs (false)
@@ -482,11 +483,15 @@ AUPlugin::AUPlugin (const AUPlugin& other)
 	, bus_outputs (0)
 	, input_maxbuf (0)
 	, input_offset (0)
+	, cb_offsets (0)
 	, input_buffers (0)
 	, input_map (0)
 	, frames_processed (0)
 	, _parameter_listener (0)
 	, _parameter_listener_arg (0)
+	, transport_frame (0)
+	, transport_speed (0)
+	, last_transport_speed (0.0)
 
 {
 	init ();