Zoom R24 USB multichannel audio interface no longer recognized

Zoom R24 USB multichannel audio interface no longer recognized

[Johan Vromans]

I'm new here so my apologies if I'm asking questions at the wrong place.
Someone told me this could be a regression in ALSA.

I'm running Fedora and have used a Zoom R24 as a USB multichannel audio
interface (8-in/2-out) for many years.

Recently I upgraded to Fedora 42 and now the device is presented as dumb
2-in/2-out USB audio interface.

"pavucontrol" does not present multi-channel profiles for the device.

The command "alsamixer -c 1" (to select the R24) gives "This device does
not have any controls.".

"qjackctl" also shows 2-in/2-out channels.

I use the device with "ardour" for multi-channel recording but that no
longer works, only 2-in/2-out channels are available.

How can I get the R24 fully functional again?

Thanks,

Re: Zoom R24 USB multichannel audio interface no longer recognized

[Jaroslav Kysela]

On 25. 06. 25 15:45, Johan Vromans wrote:
> I'm new here so my apologies if I'm asking questions at the wrong place.
> Someone told me this could be a regression in ALSA.
> 
> I'm running Fedora and have used a Zoom R24 as a USB multichannel audio
> interface (8-in/2-out) for many years.
> 
> Recently I upgraded to Fedora 42 and now the device is presented as dumb
> 2-in/2-out USB audio interface.
> 
> "pavucontrol" does not present multi-channel profiles for the device.
> 
> The command "alsamixer -c 1" (to select the R24) gives "This device does
> not have any controls.".
> 
> "qjackctl" also shows 2-in/2-out channels.
> 
> I use the device with "ardour" for multi-channel recording but that no
> longer works, only 2-in/2-out channels are available.
> 
> How can I get the R24 fully functional again?

Could you show us output from `alsa-info.sh` script ? URL should be enough.

				Jaroslav

-- 
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.

[SOLVED] Re: Zoom R24 USB multichannel audio interface no longer recognized

[Johan Vromans]

On Wed, 25 Jun 2025 15:45:17 +0200, Johan Vromans <jvromans@squirrel.nl>
wrote:

> Recently I upgraded to Fedora 42 and now the device is presented as dumb
> 2-in/2-out USB audio interface.

Sorry, false alarm.

The R24 was connected via a KVM/USB switch, and that played tricks. After
connecting the R24 directly, or via a decent hub, the problem disappeared
and all channels are available again.

Apologies for the disturbance.