Important notice: set your audio buffers to 64x3!!

[rerdavies]

Important notice: The 1.2.34 release chanced the default value for audio buffers to 64x2. This is seems to be an exceptionally bad choice, that causes drastic audio underruns when cpu use is high, and sometimes even stops the realtime audio thread altogether.

For USB audio adapters, buffers should always be set to x3. This is an old piece of lore that used to apply to Jack Audio devices, but I thought did not apply to ALSA devices. It turns out that it very much does!

If your audio buffers are set to 64x2, please change them to either 64x3, or 32x3. I think you should not experience audio dropouts using 32x3 audio buffers; but 64x3 seems to be bullet-proof even under very high CPU load.

[rerdavies]

I've been playing, a bit, with using 16x4 buffer settings. It seems surprisingly stable, and might have lower round-trip latency than 32x3.(If anyone should know for sure, it should be me, but I don't). Superficially, it seems pretty stable even with 50%+ CPU loads.

I've been tied down with development tasks, so I haven't had a chance to try this in actual live performance to see if it's rock solid. I do development work on my actual Pi, and PiPedal requires large buffers when the pi is under heavy load. I have, however, let PiPedal run overnight with no underruns at all over 8 hour periods. So I think it might actually be a good setting.

Let me know what your experiences are.