[LAU] Soundcraft MTK22 + jack: first 16 channels silent

Paul Davis paul at linuxaudiosystems.com
Fri Mar 16 17:21:01 CET 2018


No idea if this is related. My MOTU Ultralite AVB has a problem with
capture. The USB audio driver gets confused about which channel is which,
and so channels 1-8 can get "mapped" as 16-24 or 24-32 (ditto for other
groups of channels). The remapping is random (it is different every time
the device is opened. It seems to affect only capture, not playback.

this is with: Advanced Linux Sound Architecture Driver Version
k4.9.0-3-rt-amd64.


On Fri, Mar 16, 2018 at 11:57 AM, Joe Hartley <jh at brainiac.com> wrote:

> On Fri, 16 Mar 2018 10:58:36 +0100
> Atte <atte at youmail.dk> wrote:
>
> > I have two computers, a laptop and a desktop box running identical
> setups: Debian stretch with 4.12.0-14.3-liquorix-686-pae kernel and jack
> version 1.9.10.
> >
> > On the laptop my mtk22 works perfectly, on the box the first 16 channels
> are silent.
>
> I don't understand what you mean by 'silent' here.
>
> If you are taking an input signal and seeing it at your DAW but not hearing
> output, check that the USB Return buttons on each channel are not pressed.
> When pushed in, the mixer is expecting those channels to take their input
> from the computer, which allows the use of plugins in a DAW to be used to
> effect the 'live' output from the mixer.
>
> You refer to "the first 16 channels".  This raises the important question
> of what happens on channels 17/18.  The MTK22 has 14 mono channel strips,
> followed by two that can accept either a mono XLR or 2 1/4" connections
> (input channels 15/16 and 17/18, followed by one that only accepts one
> or two 1/4" (input channels 19/20), then finally one that takes either 2
> RCA
> or a USB input (channels 21/22).
>
> What are these upper channels (17-22) doing differently than the others
>
> > 1) the box worked perfectly with the mtk22 when I ran debian 8 (jessie)
> > 2) the box doesn't work even with the build in usb ports
> >
> > I'm suspecting "something" might be grabbing the first 16 channels of
> the mtk22 somehow, tried disabling pulseaudio (sudo chmod -x
> usr/bin/pulseaudio and rebooting), still doesn't work.
>
> I can't speak to anything pulse related as I don't use it and don't
> install it on my machines (Arch does not make it a dependency like other
> distros).
>
> It could be a JACK routing issue with some config persisting from something
> else.  Have you looked at the routing table, both at the JACK and at the
> DAW
> levels?
>
> --
> ======================================================================
>        Joe Hartley - UNIX/network Consultant - jh at brainiac.com
>  Without deviation from the norm, "progress" is not possible. - FZappa
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