diff --git a/libs/ardour/ardour/audio_diskstream.h b/libs/ardour/ardour/audio_diskstream.h
index 401ed9ec19..23744dfc57 100644
--- a/libs/ardour/ardour/audio_diskstream.h
+++ b/libs/ardour/ardour/audio_diskstream.h
@@ -146,7 +146,7 @@ class AudioDiskstream : public Diskstream
 		}
 	}
 	
-	LinearInterpolation interpolation;
+	CubicInterpolation interpolation;
 
 	XMLNode* deprecated_io_node;
 	
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 5a0e033353..6daaac51d0 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1019,7 +1019,7 @@ class Session : public PBD::StatefulDestructible, public boost::noncopyable
 	volatile double             _transport_speed;
 	double                      _last_transport_speed;
 	double                      _target_transport_speed;
-	LinearInterpolation  interpolation;
+	CubicInterpolation          interpolation;
 	
 	bool                     auto_play_legal;
 	nframes_t               _last_slave_transport_frame;