diff --git a/gtk2_ardour/midi_tracer.cc b/gtk2_ardour/midi_tracer.cc
index bf3853c873..b64daa5c04 100644
--- a/gtk2_ardour/midi_tracer.cc
+++ b/gtk2_ardour/midi_tracer.cc
@@ -201,7 +201,7 @@ MidiTracer::disconnect ()
 }
 
 void
-MidiTracer::tracer (Parser&, byte* msg, size_t len, samplecnt_t now)
+MidiTracer::tracer (Parser&, MIDI::byte* msg, size_t len, samplecnt_t now)
 {
 	stringstream ss;
 	char* buf;