Most of the gay expats I know do in fact frequent the gay areas (when they're open). That's why most of them are here.
As far as the music volume goes:
Lights going down and music going up (as you stated) is to be expected in bar scenes run by younger people. If you want a quiet more subdued environment - then it would probably be best if you went to bar scenes which cater more to older people. The Pattaya Marriott has a small piano bar on its lower level - accompanied on occasion by a string quartet which comes to mind.
You can't have your cake and eat it too. If you want to party and have sex with young people you need to learn how to accept the generational differences. If you think your money can change any of this, you're sadly mistaken.