When you create a track 1 (e.g. using TTS-1), put some MIDI notes in there and then add a Bus "D" (which outputs then to Master).   Then set the outout of that track 1 to  Bus "D".   Then SOLO the Bus "D" Play back; You hear the output of TTS-1 Then freeze track 1. => the created waveform is pure silence, although its routed to Bus "D" which is SOLO and although playback works for it... See in this example project: FreezingTest.zip