The MPC is a really versatile tool, but u have to give it time at first. The first month was all it took and then I really understood the feature set and started to be able to experiment.
My advise as cliche as it sounds - Read the Manual.
And google anything that isnt in there. Trust me on that.
Another good resource is YouTube.com. (just try searching for mpc1000)
You often have to put in to the time if you want the full return if u feel me!?...lol.
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But regarding your dilemma - the quickest fix to your problem lies in the PROGRAM MODE. From there, you want to curser over to the field thats designated "Lvl" - then press your WINDOW key.
At this window you can alter all of the basic envelope, or ASDR attributes that need to be f@cked with.
Also - make sure u audition the sound as u change parameters to hear what your doing....