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

Joe Hartley jh at brainiac.com
Fri Mar 16 16:57:13 CET 2018

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

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

       Joe Hartley - UNIX/network Consultant - jh at brainiac.com
 Without deviation from the norm, "progress" is not possible. - FZappa

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