I have a 2011 gt with the base stereo, and all that it has to connect an mp3 player is an aux jack, no usb. I have noticed that the sound quality is much, much better with a usb connection than with the aux jack. I hate having to listen to all the digital music that I purchase through such a crappy connection, any reasonable solutions?

 

Try using another source to see if it could be the device you are using. Also try turning the volume down. You could be getting some distortion because of too much drive from your device. Hope this helps.

Bob