I can't find a good way to play my guitar along with music on my iOS device. The problem with GarageBand is that I can't adjust the guitar and the music separately, because I want loud guitar and quiet music. Also the music gets a nasty echo effect.
There is another app called David Ellefson that allows me to select a song from my playlists to play along with, but music quality is awful and the guitar is too quiet even at 100% volume.
Is there any difference when connecting the guitar via the headphones jack vs. with a USB cable and the cam. connection kit?