diff --git a/libs/ardour/ardour/audio_diskstream.h b/libs/ardour/ardour/audio_diskstream.h
index ad3b1adde2..55cb747a4c 100644
--- a/libs/ardour/ardour/audio_diskstream.h
+++ b/libs/ardour/ardour/audio_diskstream.h
@@ -146,7 +146,7 @@ class AudioDiskstream : public Diskstream
 		}
 	}
 	
-	Interpolation interpolation;
+	LibSamplerateInterpolation interpolation;
 
 	XMLNode* deprecated_io_node;
 	
diff --git a/libs/ardour/ardour/interpolation.h b/libs/ardour/ardour/interpolation.h
index d0ba3c48bc..cec951c841 100644
--- a/libs/ardour/ardour/interpolation.h
+++ b/libs/ardour/ardour/interpolation.h
@@ -8,20 +8,20 @@
 
 namespace ARDOUR {
 
-class Interpolation {
+class LibSamplerateInterpolation {
 protected:
 	double   _speed;
 	
-	SRC_STATE*            state;
-	std::vector<SRC_DATA> data;
+	std::vector<SRC_STATE*>  state;
+	std::vector<SRC_DATA*>   data;
 	
 	int        error;
 	
 	void reset_state ();
 	
 public:
-        Interpolation ();
-        ~Interpolation ();
+        LibSamplerateInterpolation ();
+        ~LibSamplerateInterpolation ();
     
         void   set_speed (double new_speed);
         void   set_target_speed (double new_speed)   {}
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 5c2c32655f..8b291dd75b 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1008,10 +1008,10 @@ class Session : public PBD::StatefulDestructible, public boost::noncopyable
 	bool                    _silent;
 	
     // varispeed playback
-	volatile double         _transport_speed;
-	double                  _last_transport_speed;
-	double                  _target_transport_speed;
-	Interpolation            interpolation;
+	volatile double             _transport_speed;
+	double                      _last_transport_speed;
+	double                      _target_transport_speed;
+	LibSamplerateInterpolation  interpolation;
 	
 	bool                     auto_play_legal;
 	nframes_t               _last_slave_transport_frame;
diff --git a/libs/ardour/interpolation.cc b/libs/ardour/interpolation.cc
index 444183a2b1..3d2f754da9 100644
--- a/libs/ardour/interpolation.cc
+++ b/libs/ardour/interpolation.cc
@@ -4,74 +4,92 @@
 
 using namespace ARDOUR;
 
-Interpolation::Interpolation()  : _speed (1.0L), state (0)
+LibSamplerateInterpolation::LibSamplerateInterpolation()  : _speed (1.0L), state (0)
 {
 }
 
-Interpolation::~Interpolation() 
+LibSamplerateInterpolation::~LibSamplerateInterpolation() 
 {
-	state = src_delete (state);
-}
-
-void
-Interpolation::set_speed (double new_speed)
-{ 
-	_speed = new_speed; 
-	src_set_ratio (state, 1.0/_speed); 
-}
-
-void
-Interpolation::reset_state ()
-{
-	if (state) {
-		src_reset (state);
-	} else {
-		state = src_new (SRC_LINEAR, 1, &error);
+	for (int i = 0; i < state.size(); i++) {
+		state[i] = src_delete (state[i]);
 	}
 }
 
 void
-Interpolation::add_channel_to (int input_buffer_size, int output_buffer_size) 
+LibSamplerateInterpolation::set_speed (double new_speed)
+{ 
+	_speed = new_speed; 
+	for (int i = 0; i < state.size(); i++) {
+		src_set_ratio (state[i], 1.0/_speed);
+	}
+}
+
+void
+LibSamplerateInterpolation::reset_state ()
 {
-	SRC_DATA newdata;
+	printf("INTERPOLATION: reset_state()\n");
+	for (int i = 0; i < state.size(); i++) {
+		if (state[i]) {
+			src_reset (state[i]);
+		} else {
+			state[i] = src_new (SRC_SINC_FASTEST, 1, &error);
+		}
+	}
+}
+
+void
+LibSamplerateInterpolation::add_channel_to (int input_buffer_size, int output_buffer_size) 
+{
+	SRC_DATA* newdata = new SRC_DATA;
 	
 	/* Set up sample rate converter info. */
-	newdata.end_of_input = 0 ; 
+	newdata->end_of_input = 0 ; 
 
-	newdata.input_frames  = input_buffer_size;
-	newdata.output_frames = output_buffer_size;
+	newdata->input_frames  = input_buffer_size;
+	newdata->output_frames = output_buffer_size;
 
-	newdata.input_frames_used = 0 ;
-	newdata.output_frames_gen = 0 ;
+	newdata->input_frames_used = 0 ;
+	newdata->output_frames_gen = 0 ;
 
-	newdata.src_ratio = 1.0/_speed;
+	newdata->src_ratio = 1.0/_speed;
 	
 	data.push_back (newdata);
+	state.push_back (0);
 	
 	reset_state ();
 }
 
 void
-Interpolation::remove_channel_from () 
+LibSamplerateInterpolation::remove_channel_from () 
 {
+	delete data.back ();
 	data.pop_back ();
+	delete state.back ();
+	state.pop_back ();
 	reset_state ();
 }
 
 nframes_t
-Interpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
+LibSamplerateInterpolation::interpolate (int channel, nframes_t nframes, Sample *input, Sample *output)
 {	
-	data[channel].data_in       = input;
-	data[channel].data_out      = output;
+	if (!data.size ()) {
+		printf ("ERROR: trying to interpolate with no channels\n");
+		return 0;
+	}
 	
-	data[channel].input_frames = nframes * _speed;
-	data[channel].output_frames = nframes;
-	data[channel].src_ratio     = 1.0/_speed; 
+	data[channel]->data_in       = input;
+	data[channel]->data_out      = output;
+	
+	data[channel]->input_frames  = nframes * _speed;
+	data[channel]->output_frames = nframes;
+	data[channel]->src_ratio     = 1.0/_speed; 
 
-	if ((error = src_process (state, &data[channel]))) {	
+	if ((error = src_process (state[channel], data[channel]))) {	
 		printf ("\nError : %s\n\n", src_strerror (error));
 		exit (1);
 	}
-
-	return data[channel].input_frames_used;
+	
+	//printf("INTERPOLATION: channel %d input_frames_used: %d\n", channel, data[channel]->input_frames_used);
+	
+	return data[channel]->input_frames_used;
 }