Don't know exactly what you mean without an example. But I'll do it with any sound/chop, hit the 16 levels on velocity on my MPC & go from the top right to the lowest left on each beat. Gives the illusion of it fadin out or echo'n whatever you wanna call it.
Yep. A lot of people do what kebeats said, chop the sound, then play with the velocity. Play the chop regularly and then play it again at a lower velocity, and then at a even lower velocity, repeat. It'll make it seem like its echoing. The SP had this back in the day but this is the broke man's SP workaround, Lol.