[Pkg-utopia-maintainers] Bug#997915: pipewire: Weird sound from external firewire interface

[Alexandre Lymberopoulos]

Package: pipewire
Version: 0.3.38-2
Severity: normal

Dear Maintainer,

I'm aware of a new release (0.3.39), but since there no
pipewire-media-session for that new version, I couldn't get rid of the
broken package warnings on aptitude.

I have an external firewire interface (M-Audio 410) and when I try to
record my guitar from it on Ardour the sound is very weird like if
some tremolo effect is applied on the source. A microfone connected to
the onboard sound card is recorded as good as it can be, just with the
usual annoying noise. The Click sound from Ardour is perfect.

The sound also has the problem even if I just set Ardour to throw the
sound to the output (same effect if the output is HDMI from the screen
or the output of the onboard sound card). The curious thing is that
when I connect the capture channel directly to the output (or passing
throught guitarix or rackarrak) the sound is perfect. It doesn't
matter if I have PipeWire running with Pulseaudio (as described in
Debian wiki, with the linked libraries) or by itself (uninstalling
Pulseaudio and rebooting). I manage the input and output connections
with qjackctl.

At this point one might think that this is something related to
Ardour, but the same occurs when I use OBS Studio, with some audio
file in a scene: I have to set the monitor of this input to Off in
Advanced Audio Settings (so I don't hear the audio in that scene).

It seems that this artifact appears on sound when the signal passes
through some software (like Ardour or OBS) towards the realworld
output (HDMI screen or onboard speaker output), whatever it comes from
(a file or the firewire interface). It seems ok when passes through
some other software (rakarrak and guitarix), whenever the source is
the same filed used in OBS, played by mplayer to guitarix to speakers
connected on the HDMI screen, or the sound captured by the firewire
interface.

I also tried audacity, but couldn't manage to make it capture sound
from the interface, just from the microphone connected to the onboard
soundcard. It does not in the graph connection of qjackctl.

Sorry for the long message, but I tried to describe the situation here
in full detail (as much as I could). Of course I can run any tests and
provide information (hardware and config details) that may help to fix
this.

Thanks in advance.

Best,
Alexandre

-- System Information:
Debian Release: bookworm/sid
  APT prefers testing
  APT policy: (900, 'testing'), (800, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.14.0-2-amd64 (SMP w/4 CPU threads)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages pipewire depends on:
ii  init-system-helpers      1.60
ii  libpipewire-0.3-modules  0.3.38-2
ii  pipewire-bin             0.3.38-2

pipewire recommends no packages.

pipewire suggests no packages.

-- no debconf information