adobe audition 2.0

ok i hooked up my mpc via usb to my computer, and a Y cable to my stereo in from my mpc and the mic jack to my computer. When i record, i get this cheap tape cassette type of sound. its not distorted or anything. Im using a IBM Thinkpad T60. Ive always used a macbook pro with audition with no problems. Just plug and play and everything sounded perfect right when I record the beat before adding any presets or anything. This is my first time using this computer since Im borrowing it and dont have the macbook pro at the moment so I gotta record with this computer for now. any help will be greatly appreciated!

TRY TO TURN DOWN YOUR GAINS
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and you should be coming from the stereo output of the mpc, .........realy you shouldnt record from a mic input, you should have a linein somewhere .