The speaker-crackle root cause -- USB-audio OUT endpoint software buffer overflow
at 3x the max packet size -- was fixed on the audio branch (de37e00) but never on
this branch. Bumping CFG_TUD_AUDIO_FUNC_1_EP_OUT_SW_BUF_SZ from 3x to 16x removes
the crackle; verified by A/B tone test (440 Hz) through the DS5 speaker. A faint
residual cadence "warble" remains (a separate root cause, not the buffer) and is
left for a later pass. Net: one firmware with BOTH native adaptive triggers and a
crackle-free speaker.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
