HDMI audio output noisy and distorted

[mr.simonski]

I have a Raspberry Pi CM4 on a Waveshare CM4-Duino with an up

When my Retropie boots up, the audio is played back by the HDMI audio out. I use a splashscreen video which is played back by omxplayer, using this pcm.card = 0 device by default (HDMI out). The audio via omxplayer sounds fine.

As soon as Emulationstation starts, the sound gets distorted and noisy. When sound is played for a preview video of a game, the playback sound scratchy and not clear. When I switch to the console and use some speaker-test, the sound is distorted as well:

speaker-test -t wac -c2 -D hw:0

When I plug in an USB sound card, the same speaker-test plays fine:

speaker-test -t wac -c2 -D hw:1

If I set up the USB sound card to be the default player via /usr/share/alsa/alsa.conf this is fine as well.

My audio devices:

$ aplay -l
**** Liste der Hardware-Geräte (PLAYBACK) ****
Karte 0: b1 [bcm2835 HDMI 1], Gerät 0: bcm2835 HDMI 1 [bcm2835 HDMI 1]
  Sub-Geräte: 8/8
  Sub-Gerät #0: subdevice #0
  Sub-Gerät #1: subdevice #1
  Sub-Gerät #2: subdevice #2
  Sub-Gerät #3: subdevice #3
  Sub-Gerät #4: subdevice #4
  Sub-Gerät #5: subdevice #5
  Sub-Gerät #6: subdevice #6
  Sub-Gerät #7: subdevice #7
Karte 1: Device [Generic USB Audio Device], Gerät 0: USB Audio [USB Audio]
  Sub-Geräte: 1/1
  Sub-Gerät #0: subdevice #0
$ aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=b1
    bcm2835 HDMI 1, bcm2835 HDMI 1
    Default Audio Device
sysdefault:CARD=b1
    bcm2835 HDMI 1, bcm2835 HDMI 1
    Default Audio Device
dmix:CARD=b1,DEV=0
    bcm2835 HDMI 1, bcm2835 HDMI 1
    Direct sample mixing device
dsnoop:CARD=b1,DEV=0
    bcm2835 HDMI 1, bcm2835 HDMI 1
    Direct sample snooping device
hw:CARD=b1,DEV=0
    bcm2835 HDMI 1, bcm2835 HDMI 1
    Direct hardware device without any conversions
plughw:CARD=b1,DEV=0
    bcm2835 HDMI 1, bcm2835 HDMI 1
    Hardware device with all software conversions
default:CARD=Device
    Generic USB Audio Device, USB Audio
    Default Audio Device
sysdefault:CARD=Device
    Generic USB Audio Device, USB Audio
    Default Audio Device
front:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    Front speakers
surround21:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    Direct sample mixing device
dsnoop:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    Direct sample snooping device
hw:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    Direct hardware device without any conversions
plughw:CARD=Device,DEV=0
    Generic USB Audio Device, USB Audio
    Hardware device with all software conversions

Where could I start to look for a solution?

[dagshocquard]

@mr-simonski were you able to find a solution to your issue? I have the same issue where the startup audio is perfect but the game selection and in game are distorted to the point of being incomprehensible.

Any suggestions would be appreciated.