diff --git a/libs/ardour/ardour/disk_io.h b/libs/ardour/ardour/disk_io.h
index d7975a7908..74eede7644 100644
--- a/libs/ardour/ardour/disk_io.h
+++ b/libs/ardour/ardour/disk_io.h
@@ -192,7 +192,6 @@ class LIBARDOUR_API DiskIOProcessor : public Processor
 	MidiRingBuffer<samplepos_t>*  _midi_buf;
 	gint                         _samples_written_to_ringbuffer;
 	gint                         _samples_read_from_ringbuffer;
-	CubicMidiInterpolation        midi_interpolation;
 
 	static void get_location_times (const Location* location, samplepos_t* start, samplepos_t* end, samplepos_t* length);
 };
diff --git a/libs/ardour/disk_io.cc b/libs/ardour/disk_io.cc
index 82b32d571e..7275d5701b 100644
--- a/libs/ardour/disk_io.cc
+++ b/libs/ardour/disk_io.cc
@@ -61,7 +61,6 @@ DiskIOProcessor::DiskIOProcessor (Session& s, string const & str, Flag f)
 	, _samples_written_to_ringbuffer (0)
 	, _samples_read_from_ringbuffer (0)
 {
-	midi_interpolation.add_channel_to (0,0);
 	set_display_to_user (false);
 }
 
@@ -167,7 +166,6 @@ DiskIOProcessor::configure_io (ChanCount in, ChanCount out)
 	if (in.n_midi() > 0 && !_midi_buf) {
 		const size_t size = _session.butler()->midi_diskstream_buffer_size();
 		_midi_buf = new MidiRingBuffer<samplepos_t>(size);
-		midi_interpolation.add_channel_to (0,0);
 		changed = true;
 	}