I thought I made a post about this a while back, but according to the search feature, I didn't.
Anyway, several months ago I purchased the original Mass Effect on Steam after playing ME2 a bit and loving the storyline and gameplay. I wanted the taste the delights of the whole series. So, being a bit impatient I downloaded it from Steam.
All goes OK, install is fine, setup is fine, go to play and I get real problems with the sound. The ambience (background noise) was extremely loud, at normal volume of my speakers it was so loud it was almost distorting them. All other sounds, voices etc were so quiet that you could barely hear most of it over the ambience.
Anyway, I did a bit of searching, found nothing. Updated all drivers, DirectX, etc and still got nowhere. Looked at Steam and Mass Effect forums, found no definate solution. I gave up and contacted Steam about a refund, they simply replied "No way, Jose" and told me to speak with the BioWare. In the end, I uninstalled it and forgot about it.
I recently played a bit of ME2 again after becoming bored with other games I usually play (MMO's) and got right back into it, completing it in a few days of play. I must say, it's one of the best games I've played for a long, long time. So after completing it and feeling like I was missing a lot from not playing the first, I decided to try Mass Effect again. This time though, I tried something that for some reason either didn't cross my mind the first time round or I never read anyone suggesting it in the previous searches.
I simply went into the Windows Sound options and turned down hardware acceleration one notch.
Loaded the game up and it worked perfectly, sound was amazing! I now have another fantastic game to play through again, twice (one for a Paragon female and the other for a Renegade male ).
Awesome!