if we talk internal synths (or even external ones hooked up by midi) the easiest way is Autosampler!
on a track load up a plugin, craft your sound with the synth, then go to menù -> sampler -> hit the small keyboard icon in the top bar (autosampler). set it the way you want and let it do its magic! it will spit out a full on keygroup program (with up to 4 velocity layers if you want).
if you want to sample an external synth, go to a track, switch it to external midi track, set up port and channel, route the synth outs back to the mpc inputs, then go menu–>sampler and do exactly the same as internal plugins!
talking one shot percussive sounds, load up a sample, tweak it, add effects etc… then from the edit program’s effect page hit Flatten Pad, it will bounce in place your sound and you have it on the same pad.
for more complex stuff you can load up whatever, write a sequence, use effects in insert and sends, do automations etc… then from the main page click on the pencil in the program area (the lower part of the screen) then hit bounce to sample.
lots of ways to do stuff in the mpc now !
of course you can also do real time:
load up a program of whatever type, go to menu—>sampler set inputs to resampling (mono or stereo), hit record and start playing your pads!
@spqr6510: AKAI ME35T 8 analog inputs to midi trigger, configurable! i just found out, they are pretty cheap on the 2nd hand market (about 80 euros), plus you can use them with other gear as well! triggering the mpc from the modular too! mmmmm…