Try Zita-ajbridge instead of alsa_in and alsa_out

[xmacex]

Better sound quality and lower CPU, according to website https://kokkinizita.linuxaudio.org/linuxaudio/zita-ajbridge-doc/

Look, science!!

a2j

alsa_in

A drop-in replacement, give it a shot.

[xmacex]

Package exists for the norns OS, and installs without problems. It's called zita-ajbridge.

However zita-a2j -d hw:1,0 -r 44100 -v gives

playback : not enabled
capture  :
  nchan  : 2
  fsamp  : 44100
  fsize  : 256
  nfrag  : 2
  format : S24_3LE
Starting synchronisation.

but not the 4 times per second tracing information. Jack devices are created.

Hypothesis: normal user is not allowed to run real-time processes. See ulimits. Thank you google.

[xmacex]

That hypothesis I believe is incorrect, at least in /etc/security/limits.d/audio.conf we find

@audio   -  rtprio     95
@audio   -  memlock    unlimited

[xmacex]

There is an internal Zita client which somebody got working https://github.com/jackaudio/jack2/issues/773.