diff --git a/libs/ardour/midi_buffer.cc b/libs/ardour/midi_buffer.cc
index c65ba58288..29bec23851 100644
--- a/libs/ardour/midi_buffer.cc
+++ b/libs/ardour/midi_buffer.cc
@@ -158,6 +158,7 @@ MidiBuffer::push_back(TimeType time, size_t size, const uint8_t* data)
 	const size_t stamp_size = sizeof(TimeType);
 
 #ifndef NDEBUG
+	if (DEBUG::MidiIO & PBD::debug_bits) {
                 DEBUG_STR_DECL(a);
                 DEBUG_STR_APPEND(a, string_compose ("midibuffer %1 push event @ %2 sz %3 ", this, time, size));
 		for (size_t i=0; i < size; ++i) {
@@ -168,6 +169,7 @@ MidiBuffer::push_back(TimeType time, size_t size, const uint8_t* data)
 		}
                 DEBUG_STR_APPEND(a,'\n');
                 DEBUG_TRACE (DEBUG::MidiIO, DEBUG_STR(a).str());
+	}
 #endif
 
 	if (_size + stamp_size + size >= _capacity) {
diff --git a/libs/ardour/midi_ring_buffer.cc b/libs/ardour/midi_ring_buffer.cc
index b25154fefb..a10ad0b199 100644
--- a/libs/ardour/midi_ring_buffer.cc
+++ b/libs/ardour/midi_ring_buffer.cc
@@ -137,16 +137,18 @@ MidiRingBuffer<T>::read(MidiBuffer& dst, framepos_t start, framepos_t end, frame
 		success = read_contents (ev_size, write_loc);
 
 #ifndef NDEBUG
-                DEBUG_STR_DECL(a);
-                DEBUG_STR_APPEND(a, string_compose ("wrote MidiEvent to Buffer (time=%1, start=%2 offset=%3)", ev_time, start, offset));
-		for (size_t i=0; i < ev_size; ++i) {
-			DEBUG_STR_APPEND(a,hex);
-			DEBUG_STR_APPEND(a,"0x");
-			DEBUG_STR_APPEND(a,(int)write_loc[i]);
-                        DEBUG_STR_APPEND(a,' ');
+		if (DEBUG::MidiDiskstreamIO && PBD::debug_bits) {
+			DEBUG_STR_DECL(a);
+			DEBUG_STR_APPEND(a, string_compose ("wrote MidiEvent to Buffer (time=%1, start=%2 offset=%3)", ev_time, start, offset));
+			for (size_t i=0; i < ev_size; ++i) {
+				DEBUG_STR_APPEND(a,hex);
+				DEBUG_STR_APPEND(a,"0x");
+				DEBUG_STR_APPEND(a,(int)write_loc[i]);
+				DEBUG_STR_APPEND(a,' ');
+			}
+			DEBUG_STR_APPEND(a,'\n');
+			DEBUG_TRACE (DEBUG::MidiDiskstreamIO, DEBUG_STR(a).str());
 		}
-                DEBUG_STR_APPEND(a,'\n');
-                DEBUG_TRACE (DEBUG::MidiDiskstreamIO, DEBUG_STR(a).str());
 #endif
 
 		if (success) {