HU settings vs mp3 player settings

[Jeeptastic]

i'm new with hooking up mp3 players in my car and just installed a new Pioneer HU with a front AUX jack to plug an mp3 player into..i just got a sweet little sony mp3 player (from woot)..both have many different equalizer/volume/sound settings and enhancements..when i first plugged the mp3 player in it sounded awful because it was using the sound settings from both devices..when i turned one ot the other the sound is much better..which way will result in the best sound?..and should volume be all the way up on the mp3 player?

[rmb2485]

I've always achieved the best results by turning off the EQ on the mp3 player. With my ipod, I turn its volume all the way up, but with my old rio I left its volume on about 3/4 because all the way up would distort the sound. Just play with the volume settings and you'll figure out what sounds good pretty quickly. Definitely turn off the mp3 player's EQ tho.