One very interesting feature I think, would be integration of brutefir or convolver into the mpd software used for playing audio.
Either of these two allows for DSP / crossover effects to be applied (I’m particularly interested in using it for digital room correction)
brutefir is extremely well optimized, at least for x86.
Anyway, this feature would be very wonderful. Very.
Keep in mind that it should be somehow applied to the general output, so that both airplay and mpd would benefit.
I’m not sure how much time Michelangelo has, though.
Could Folve be a solution? I get it to run:
http://volumio.org/forum/dsp-with-raspberry-hifiberry-and-volumio-drc-folve-t672.html
Works well in my configuration with a HiFiBerry.