diff --git a/libs/ardour/session_process.cc b/libs/ardour/session_process.cc
index 9902e5a1e3..4d18aaf73c 100644
--- a/libs/ardour/session_process.cc
+++ b/libs/ardour/session_process.cc
@@ -834,6 +834,16 @@ Session::process_without_events (pframes_t nframes)
 
 	get_track_statistics ();
 
+	/* XXX: I'm not sure whether this is correct, but at least it
+	   matches process_with_events, so that this new frames_moved
+	   is -ve when transport speed is -ve.  This means that the
+	   transport position is updated correctly when we are in
+	   reverse.  It seems a bit wrong that we're not using the
+	   interpolator to compute this.
+	*/
+	   
+	frames_moved = (framecnt_t) floor (_transport_speed * nframes);
+	
 	if (frames_moved < 0) {
 		decrement_transport_position (-frames_moved);
 	} else {