Re: [PATCH] ALSA: usb-audio: Add mixer map quirk for Audient iD24

[Takashi Iwai <tiwai@suse.de>]

On Mon, 31 Aug 2026 21:58:55 +0200,
Peter Drabik wrote:
> 
> The Audient iD24 (2708:000d) exposes feature unit 12 as a 4-channel
> "Speaker Playback Volume" control (cmask 0xf, -127..0 dB).  The device
> does not actually apply this volume to all of its output channels: the
> left main output ignores it and stays at 0 dB, while the right main
> output honors it.
> 
> When userspace (PulseAudio / PipeWire in a stereo profile) adopts this
> control as the master playback volume, any setting below maximum
> produces a stereo imbalance on the main outputs.
> 
> This was verified against the device's internal meters: with the
> control set to 107/127 (-20 dB) on all four channels and a digitally
> identical L/R sine played back, both DAW return meters read the same
> level while the right main output metered exactly 20 dB below the
> left.  Restoring the control to 127 (0 dB) restored the balance.
> 
> Rename the control to "Monitor Mix Playback" so that it is not picked
> up as the stream's master volume control, in line with similar quirks
> for other devices.  The control remains accessible for manual use.
> 
> Signed-off-by: Peter Drabik <drabik.p@gmail.com>

Applied now.  Thanks.


Takashi