Problem with no sound in psx emulator

[Strongground]

productPi Model or other hardware: 3 B V.1.2
Power Supply used: Official one, that came with the Pi
RetroPie Version Used: 4.8
Built From: I used the "Raspberry Pi Imager" tool to load it onto a SD card
USB Devices connected: Generic USB controller
Controller used: see above
Error messages received: see message
Guide used: I used the installation guide on this page.
File: Every PSX ROM I tried so far (about ~100)
Emulator: PSX

How to replicate the problem:

1. Start Retropie, custom intro video will play (with sound).
2. Main menu shows, I can configure, go into menus, I hear menu sounds.
3. Start any PSX game. It will play fine, (albeit some with graphical glitches like triangles only rendering from certain perspectives etc. but those are game/emulator specific problems), I can use "save game state" feature, everything works. Except sound. No sound from game videos, no CD-sound, no sound whatsoever.

Notes: I used the 3.5 mm jack on the Pi. I don't have a monitor with speakers so I can't test HDMI audio - then again, the sound works fine for the intro video and Retropie menu.
No error messages have been observed. I did look into a runcommand.log at one point but I am not sure what to look for - I think there where no audio related errors.

[mitu]

Is the sound working in other systems and it's just the PS1 system doesn't have audio ? Did you use the 'save settings' menu in RetroArch at some point while playing a PS1 game ?

[Strongground]

@mitu Thanks for your help. In fact the game sound is working when using HDMI. I was originally not going to, so this would've been a huge problem. But since I am now using HDMI, everything is fine.