If the sound card is compatible with Linux (should be), then all you need is disable the on-board sound card and it should be automatically used.
Some details, added over time by various RetroPie users, are in Sound docs.

@yoc1983 said in Retroarch audio problem (digital/I2S):

Built From: Pre made Image, Wolfanoz Raspberry Pi 4 Supreme Pro

We don't support 3rd party images - use the image from retropie.org.uk/download if you want support here.

@mxc0bbn Can you describe your setup, as indicated in https://retropie.org.uk/forum/topic/3/read-this-first

@n2185x the distortion I faced with lt-atari800 audio was resolved by applying the patch in this linked thread. The patch, to my knowledge, has not made it into the libretro core

I can confirm that applying this patch and recompiling fixed my audio quality and buzzing

https://retropie.org.uk/forum/topic/22530/lr-atari800-buzzing-sound/4

@roslof said in lr-mame: Cinematronic Changes and the Pi 4B:

not update until optimizations are in place

Well, i doubt that's gonna happen soon, netlist emulation has been around for 10 years and always required a somehow good cpu. It'll probably take some time before they make another breakthrough performance-wise, and i'm not sure the MAME team even care about performance in the first place.

@roslof said in lr-mame: Cinematronic Changes and the Pi 4B:

Of course fb-neo is another alternative

Actually, this driver is the only vector games driver we are missing. In my previous post i was talking about netlist emulation in general, since it's used in most 70s and early 80s games, i guess we'll keep using samples for now.

RetroPie updates have nothing to do with the audio - it's the OS updates (kernel/firmware) that can affect it. Of course, using an experimental/beta driver might not be the most stable configuration at this time, so you might encounter issues with it from kernel/firmware version to another.

@ReadyPlayaWon I'll keep that in mind in future situations, but I've had a chance to confirm and the video volume isn't an issue when in HDMI mode. The issue is only with the headphone jack. I'll continue looking for a programming solution.

@UberLumby You can adjust the volume just for the pcengine system by editing the retroarch.cfg in \\retropie\configs\pcengine and adding a line with the audio_volume option:

audio_volume = -1.00

This confusion happened over the course of weeks after I disabled the onscreen help. Forgive me. I've got some grey hair in my late 30s. :D

@darrena092 said in Idea: Audio Device Selector in RetroPie-Setup:

I think it might be a good idea to add an audio configuration menu to RetroPie-Setup, which allows the user to select a default output device and automatically updates the ALSA config based on the user's preferences. This could also be added in EmulationStation to the RetroPie menu for easy access.

There is already an Audio settings menu in EmulationStation - in the RetroPie system. Right now it only works for choosing the audio output for the Pi's onboard audio - i.e. no USB/I2S sound card support. It should be possible to extend it to support other audio options.

The only issue would be the EmulationStation own Audio menu, where you can choose the Card and Device (volume control) - the ALSA name of the default mixer varies, depending on the audio card, but the list of Audio Devices is fixed (in source).

My problem was solved in the strangest way. Dust.
Thanks to you all

@BGallagherLA I've just watched your videos . Those are really nice! The main point is you can play "nice and soft" on RBPi4.
If you check my streamings out you'll see the results are the same as yours. But unfortunetely unplayable on RBPi3. See you on Twitch!

Didn't realise it was quite so simple. Updated to 2.9.1 and can see the extra setting within the screensaver settings. All working perfectly.

Should it help anyone in the future the steps I went through were

In emulationstation, go to Tools > RetroPie Setup.
Once in, select Update RetroPie-Setup script and select yes to update it.
Now select Manage packages, followed by Manage core packages, select emulationstation and finally Update from binary.
Once that's done restart EmulationStation

@mitu said in Audio Issue - RPi 4:

Sorry, glossed over that. What theme are you using in EmulationStation ?

Pixel.

@BuZz Right you are! I tried that one first but it still said no signal. Seems the HDMI cord I got with my Canakit is a bit touchy... Thanks!

Thanks a lot, i solved it!!!