Akai MPC 5000 Reference Manual page 185

The MIDI page will be displayed.
If you set this field to ALL, the MPC5000 will receive all channels. If you select any channel from 1 to 16, the MPC5000 will receive only the
selected channel.
The MIDI page will be displayed.
This will allow the MPC5000 to play a different sound for every incoming MIDI channel.
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To set which track plays which sound, do the following:
The MPC5000 can up to 32 sounds Multitimbrally.
Setting MIDI A01-A16 will receive the corresponding MIDI channel through MIDI IN 1.
Setting MIDI B01-B16 will receive the corresponding MIDI channel through MIDI IN 2.
Tracks set to MIDI C01-D16 will ignore incoming MIDI.