I'm not so sure that's the issue, one of the pcs has had 3DGS reinstalled recently because of some problems before, and it still has issues.

I also don't think it's the sound card because each pc has a different card on it, I've had the issue on all the pcs I've tested it on. As I mentioned before, changing the balace of the sound does next to nothing. Only when the sound is turned to -100 does it work semi correctly, and even then it's random if it works at all.