Do you have your turntable hooked up to a dj mixer than to the mpc? If you do mess with the eq's on the mixer it would help a whole lot... and if you don't you should get one
if there is another low freqency such as a kick in the bass sound ur trying to sample a low pass filter wouldnt work because the kick will be in there as well as the bass
naw i got it i was doing a low pass filter but setting the fequencies high thinking it was gonna affect it more when im really supposed to set them really low