I wonder if there are any news according the usage of two differnet soudcards. I have an old Terratec EWS88MT and a Behringer XR18 , both get recognized by jack, both standalone run without any troubles in ubuntu-studio 20.04 with jack2.
Can I use them together? That would be great.
Do I have to create a “virtual” Soundcard" in .asoundrc or does jack2 manage to set the clock for both?
You’re usually much better off using alsa_in/out (or better yet zita-ajbridge) tools.
Unless if you want to use one device for input, and the other soundcard for output (not combine both In + Out of both). In that case Ardour/ALSA (no jack) makes this trivial.
actually I want to use 8 Ins from the Terratec and all 18 Ins from the Behringer.
Output through the Behringer.
I don’t understand why to put alsa_in or zita-a2j inbetween when jack already offers all Ins and Outs?
Can’t jackd sync the two cards by default?
To use multiple audio-interface their sample-clocks have to be synchronized. One interface is the master, and data from others has to be resampled to match the clock of the main device.
In your case: start jackd using the Behringer (for both in and out), then run alsa_in -d hw:XXX (replace XXX with the ID of the Terratec) to make those inputs available in addition to the behringer ones.
Alternatively you can use zita-a2j -d hw:XXX – zita-ajbridge is a drop-in replacement for the alsa_in/out tools which come with jack. zita-aj2/j2a offers better quality at lower CPU usage.
You need to stop those clients before stopping jackd. If you start them from a terminal just use ctrl-c in the terminal, otherwise you need to send a signal to the processes to stop. I’m not familiar with ubuntu-studio-controls, but with the typical qjackctl GUI software for configuring jackd there is a section to configure starting and stopping other applications when you start and stop jackd, perhaps ubuntu-studio-controls has something similar.
Otherwise you can just use “killall zita-a2j” and “killall zita-j2a” after you stop studio controls to kill those processes.
Finally after 2 days of hard work I managed to get things to work as wanted.
I still don’t know where to configure the zita-ajbridge in latest studio controls, but with a mix with qjackctl it works.
Uncreative time, though. I prefer to work on music rather than messing around with technical issues