DSP Manager helps some, and dalingren, who does a lot of the kernel tweaking for CM7, has made an app that he says should help with a lot of the audio issues:
http://forum.xda-developers.com/show....php?t=1104039
I haven't been motivated to mess with it much since the day I was running tests.
Someone also mentioned this guy to improve sound output through the headphone jack:
http://www.crutchfield.com/p_127SNI1...se-Filter.html