Samples Dropping out

why do some samples drop out while playing, and what can i do to combat this...they play fine solo, but when everything's playing together that sh*t'll drop out...

maybe polyphony in the Program settings?

phasing.certain frequency's are hitting the same frequency and cancelling out each other. if you have two samples playing over each other, and they are very similar, pan one sample full to left, pan other full to right. there are many other ways to get around this

how many programs are u using??? mines does the same thing and i dont know how to fix it... it does it on the jj os and the akai os...
http://www.mpc-forums.com/viewtopic.php?t=76347

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it ain't hittin' the same keys...i was tryin' to remix a jay-z song...and the verses would go out after one word...or i would have to take out some of the synths, etc...i probably had about ten programs goin...