The problem you're describing is depressingly normal. Camera and smartphone manufacturers put lots of care into video and pixel count but not audio distortion or a larger aperture. 14MP P&S Canons in particular often have unspeakably bad audio, which is why I researched and bought a Panasonic DMC-ZS3: because of its rare audio functions, level limiter and accurate HD video, all of which are absent features in smartphones and rare in mid-priced point and shoots. That, the amazing 12X analog zoom and Leica lens are why I use the ZS3 for amateur concert vids.
In terms of *recording* music live, my brief Evo trashed the Epic (though it didn't sound nearly as good as the ZS3). In terms of *listening* to music, the Epic was far better than the Evo or indeed any other phone I've ever owned. I A/B'd the Epic with the iPhone 3GS and there was no comparison; I've yet to compare the Epic with the iPhone 4, though I did look at the screens side by side.
If you're serious about video with sound, I suggest you get one of the decent Sony field recorders (like the PCM-D50) and do what my professional friends do when they're being ghetto: sync it to your phone video later or on the fly (a friend of mine who engineers for Wynton Marsalis does the second thing for fun).
My second suggestion: look into a USB analog-digital converter and into the Epic's ability to support it. If you're serious and it will actually help you, let me know and I'll ask around.
When I used to record my live shows onto minidisc, the signal distorted unless I used an otter box with imbedded stereo mics, bass cut and mic pre to mediate distortion. The thing was made by Sound Professionals to my specs, but I just looked at their web site and didn't see the order form that allows you to build it. You can call them, explain your problem and ask them if they can still build one for you.
Here's the closest thing they still make -- a considerably stripped-down version:
Here's a useful forum for tapers who want to capture decent AV of live performances:
Here's the thread that cemented my choice of camera for live AV last year: