I installed NITdroid on my n900 just out of curiosity and I was amazed of the sound quality using internal speakers. The sound is A LOT softer without ANY distortion what so ever - even on full volume and the volume is about the same. There's also a lot more bass than maemo audio through same speakers.
With headphones it's not such a big of a difference, but still sound like there's less distortion.
So.. I figured out that there's sth wrong with how maemo5 handles the audio data or how it handles the hw responsible for amplifying the signal.
Is this component closed source? Maybe it'd be possible to port some of these from android to maemo?