no you don`t need a midi keyboard you can just use the mpc as a midi controller and via midi the rack sounds will be played by the pads( u prob know but i`ll say this anyway - even though the sounds are being played by hitting the pads the actual audio is still coming from the synth out, not the mpc - read about midi if u dont understand this, if u do then i`m very sorry to sound so patronizing!) which if set right work stright away if u turn them on in midi settings on mpc.
you get the full range that you`d get from a keyboard , it just means that you have to swith between banks to get higher, lower notes.
however, i myself find this a bit tedious if wanting to write quite complex synth melodys its great for addin a bit of bass line and general sounds but for full on composition you cant beat having a keyboard.
but why not just try the rack midi`d up and then buy a midi keyboard in future if u think u need one.
but if you`ve got the room think about getting synth with keys, much easier to get to grips with if its your first one.
check out some synths and rack gear on the net , youtube etc and have a think.
there is so many ways of doin it nowadays its all down to personal preferance.
but to answer your origional question again no you dont need a keyboard and yes i have ran a synth (novation a station) just from mpc but found it easier with keys too ( i run three synths and a didgital piano all thru my mpc via midi)
best of luck mate, and if your after a hardware synth thats not to big check out novations, they got some wicked bass lines as pre sets and real analouge sounding, all depends what u after though
now go search...
later mate
E
