One of the only disappointments I had with my EVO was that the audio quality through the headphone jack seemed muffled and quiet compared to my old iPhone. This wasn't a huge issue but very noticeable when listening to music in my car through the AUX input. After doing the following, I'm happy to say that the quality now even surpasses the iPhone. Installed the paid version of MixZing - the price was kinda steep but well worth it since it comes with an EQ. Boosting the overall gain tweaking the low frequencies has done wonders - best music app IMO hands down! (Following Requires Root and NAND): Flashed a custom 2.2 ROM - the newer ROMs are using modified versions of HTC's source kernel to boost the audio volume. I prefer BakedSnack 1.4 using his included kernel. Better audio quality and better battery life to boot. Flashed the workaround (or manually edit build.prop) to temporary disable stagefright. This fixes the audio issues with Pandora running on 2.2. I'm very happy with my setup now - anyone else have other suggestions?