diff --git a/libs/ardour/mtc_slave.cc b/libs/ardour/mtc_slave.cc
index 62c1b77af1..b73742d7f9 100644
--- a/libs/ardour/mtc_slave.cc
+++ b/libs/ardour/mtc_slave.cc
@@ -571,7 +571,7 @@ MTC_TransportMaster::position_string() const
 std::string
 MTC_TransportMaster::delta_string () const
 {
-	char delta[80];
+	char delta[128];
 	SafeTime last;
 	current.safe_read (last);
 
@@ -580,8 +580,14 @@ MTC_TransportMaster::delta_string () const
 	if (last.timestamp == 0 || reset_pending) {
 		snprintf(delta, sizeof(delta), "\u2012\u2012\u2012\u2012");
 	} else {
-		snprintf(delta, sizeof(delta), "\u0394<span foreground=\"green\" face=\"monospace\" >%s%s%" PRIi64 "</span>sm",
-				LEADINGZERO(abs(_current_delta)), PLUSMINUS(-_current_delta), abs(_current_delta));
+		if (abs (_current_delta) > _session->sample_rate()) {
+			int secs = rint ((double) _current_delta / _session->sample_rate());
+			snprintf(delta, sizeof(delta), "\u0394<span foreground=\"green\" face=\"monospace\" >%s%s%d</span><span face=\"monospace\"> s</span>",
+			         LEADINGZERO(abs(secs)), PLUSMINUS(-secs), abs(secs));
+		} else {
+			snprintf(delta, sizeof(delta), "\u0394<span foreground=\"green\" face=\"monospace\" >%s%s%" PRIi64 "</span><span face=\"monospace\">sm</span>",
+			         LEADINGZERO(abs(_current_delta)), PLUSMINUS(-_current_delta), abs(_current_delta));
+		}
 	}
 	return std::string(delta);
 }