There's a guy called "dom" on the RPi forum who seems to be involved in audio development. I've seen his interventions in a couple of audio related threads, and i got the information about the analog output being simple filtered PWM off one of his posts.
Might be interesting to get in touch with him.

Pierre.

2012/8/29 Tedb0t <lists@liminastudio.com>
This is what I'm curious about; who is doing this alsa development, where, and can we pitch in?  We are all interested  in getting the sound working better on the Pi...

That said, it seems like the jury is out on if it's an alsa problem or a Pd problem.  I seem to have experienced both.

—Tedb0t

On Aug 29, 2012, at 6:46 AM, geoffroy wrote:

With the PI the alsa is in alpha development on the arm platform and therefor won't be at it's best for a little while. The floating point integration in the latest system made the audio a lot better, as on the first gen OS of the PI the audio was just impossible.


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