Okay, so I just recently purchased a new MBP, and occasionally I like to record acoustic guitar via cable to the laptops built-in input. For some reason whenever I record the input is very low and hardly audible unless I crank up the dial on my mic settings on the guitar itself, which doesn't produce a clear sound. This happens in both Logic and GarageBand, and I've made sure that the Line-In input volume was set to max.

Before I got the new macbook pro I had the 1st Gen which recorded fine, does anybody know why the new ones do this?