I recently installed Jelly Bam 7.6.2, which is a Jelly Bean 4.2.2 ROM consisting of CM 10.1, Paranoid Android and AOKP, and it includes hacks for AC!D, Sony's ClearAudio+ and Beats DSPs. The Beats DSP is basically a glorified THUMP THUMP booster that actually works quite well but can become nauseating on the two highest settings. The ClearAudio+ hack is a lot more interesting. It has a slider you can use to change the sound signature. A picture will suffice here.
I don't notice much change when I move the slider around while music is playing, but turning the feature off completely cuts the volume by about 30%. Whether or not the slider does anything, the sound quality of Galaxy Note with its Yamaha DAC is now on par with my Infuse 4G and its Wolfson DAC. Using PowerAmp with no EQ and all bass boost DSPs turned off, I really can't a difference between them now. It's very strange that a software fix will make two different DACs, on technically inferior to the other, sound virtually the same.