The common attenuation made playback too quiet. Inputs are now summed
without attenuation; docs note that loud simultaneous inputs can clip.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
SBC medium, not the larger buffer, removed the headphone relay dropouts,
so cut dmix, bluealsa-aplay and alsaloop buffers to 200 ms and the
Shairport backend buffer to 0.15 s. Verified by listening (iPhone ->
headphones, with AirPlay mixed in) with no RTP loss or underruns.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
One-shot bluetoothctl pairing exited before SSP finished, leaving the
headphone paired but not bonded, so it was lost on reboot. Pair inside a
single bluetoothctl session with a persistent agent, and clear temporary
pairings first. Document that SBC medium + 500 ms buffer removed the
iPhone -> Radxa -> headphone dropouts, verified by listening and logs.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
