This post on their help site is the most definitive thing I’ve found:
Q: Is it possible to resample the Tracker’s audio output?
A: No, this is not possible. Tracker can’t play its patterns and record audio at the same time due to its hardware limitations. It’s not a matter of a firmware update. […] One can use the “render selection” function in order to bounce steps or selections of steps from one or more tracks at the same time to a single audio file.
The simple rule is that the Tracker can’t both record and generate audio. It can record audio but not generate it (as it does with an offline render or when “bouncing steps” as per above or when straight-up sampling in Sample Record mode). Or it can generate audio while not recording (as it does when playing back samples in Pattern or Song mode). But it cannot do both.
This sometimes gets confusing because the Tracker is also pretty capable when it comes to MIDI. But remember, MIDI is not audio, so it doesn’t break the rules. So you can record audio from external synths “generated” by MIDI in the Tracker’s sequencer because the Tracker itself is not generating audio — it’s just sending MIDI. Or you can “record” MIDI while the tracker is playing back a pattern because audio isn’t actually being recorded — just MIDI.
But at the end of the day, the Tracker still cannot generate and record audio at the same time. And it seems like a very intentional, irreversible, hardware-bound choice on the part of Polyend.
