diff --git a/libs/ardour/segment_descriptor.cc b/libs/ardour/segment_descriptor.cc
index 336a8b8aeb..754b127053 100644
--- a/libs/ardour/segment_descriptor.cc
+++ b/libs/ardour/segment_descriptor.cc
@@ -77,7 +77,7 @@ SegmentDescriptor::set_duration (samplepos_t s)
 		/* XXX error */
 		return;
 	}
-	_position_samples = s;
+	_duration_samples = s;
 }
 
 void