@ddw_music said:
At this point, I'm pretty well satisfied that Pd's behavior is fine, and your patch is doing the right thing. So the real point of this test is to find out the boundaries of Audacity's correct behavior, not really anything else.
Likewise, although I'm a little surprised, given that Audacity has been around for so long, and since I'm playing back at the same sample rate no interpolation is required. It's just sending the sample data in blocks to the audio driver or host. Maybe something to do with the latency setting? I'm just letting it default, I've never played around with it before.