Mac midi help

I'm having trouble getting my midi to work. I can sequence drum sounds from the computer on my mpc just fine, but when I try and use a new track and new instrument, it changes the sound from track one to the sound I'm trying to use for track two. So drums become piano. Any advice?

get your midi channels right, 1adevice1 on the mpc should be midi channel 1 and so forth, make sure you change the track in conjunction with the instrument bro, if your not already doing that

Im just getting into production on mac w/ my mpc2000xl. Can we delve deeper into the whole conntecting to the computer. Im really green on Comps (I havent had a computer since '99).... I use a m-audio uno midi/usb device and run Logic Express. What about using the 1/8" phono input? I go into my audio setup, and when line in is selected, I see that the computer is getting sound, but no audio out over the speakers. How can I use this option, or can I with Logic? (I'm not sure, but I think Logic strictly uses MIDI....)