iDeaS really isn't the best emulator to be playing DS games on. Have you tried No$GBA or DeSume?
What?DeSmuME 0.9.5 is better than Ideas in almost every aspect. I don't see any reason for using Ideas
The new code of Desmume about syncro has fixed almost all the sound. Literally with a Decent pc there is no flaws.Actually, iDeaS has indeed had a pretty clean sound plugin in the past. It was just broken for a long time. You can find it in my signature.
Unless the official sound plugin is reverted to the old one, it's normal that many people will find the sound in iDeaS unbearable... (remember Poki#3, Lino?)
That's not the only problem. There are more important problems such as sprite ordering and layer blending/ordering being broken since 18.104.22.168. Not to say that iDeaS is currently no longer being worked on, because of the problems Lino is having, and that's quite unfortunate... (even Emucraze is being moved to another host)
Anyway, for support, the issue described in the first post should be fixed by switching to 22.214.171.124 (you can find it here for instance, with many plugins in it).