diff --git a/libs/backends/jack/jack_session.cc b/libs/backends/jack/jack_session.cc
index b55c8ee66f..f205234d8d 100644
--- a/libs/backends/jack/jack_session.cc
+++ b/libs/backends/jack/jack_session.cc
@@ -128,7 +128,7 @@ JACKSession::timebase_callback (jack_transport_state_t /*state*/,
 	TempoMetric metric (tempo_map.metric_at (tf));
 
 	try {
-		bbt = tempo_map.bbt_at_sample (tf);
+		bbt = tempo_map.bbt_at_sample_rt (tf);
 
 		pos->bar = bbt.bars;
 		pos->beat = bbt.beats;