diff --git a/gtk2_ardour/engine_dialog.cc b/gtk2_ardour/engine_dialog.cc
index e0c2e10d6b..b144019ece 100644
--- a/gtk2_ardour/engine_dialog.cc
+++ b/gtk2_ardour/engine_dialog.cc
@@ -1608,7 +1608,7 @@ EngineControl::output_device_changed ()
 string
 EngineControl::bufsize_as_string (uint32_t sz)
 {
-	return string_compose (P_("%1 sample", "%1 samples", sz), sz);
+	return string_compose (P_("%1 sample", "%1 samples", sz), to_string(sz));
 }
 
 string