Performance Mode in the XP-50 set to LAYER Mode can be zoned so that an
instrument can occupy an area of the keyboard while another instrument occupies
another. Ultimately, the XP-50 can set 16 different zones, each for a different
Part/instrument. Use the following procedure to split the keyboard:

1) Press PERFORM.
2) Press EDIT so it is lit.
3) Press COMMON.
4) CURSOR DOWN to KEY MODE and select LAYER.
5) Press PALETTE so it is lit.
6) CURSOR DOWN to KEY RANGE LOWER and select Part's Lower Ranges.
7) CURSOR DOWN to KEY RANGE UPPER and select Part's Upper Ranges.
8) Press EDIT so it is not lit.
9) Press TX and RX buttons together.
10) Press the PART buttons (under the window), to select the Parts to use with
the split.
11) Use WRITE procedure through DISK/UTILITY button to write your new
performance into the USER Bank.

Here is an example:

Part 1 (A Bass patch). Key Range Lower: C-1 Key Range Upper: B3
Part 2 (A Piano patch) Key Range Lower: C4 Key Range Upper: G9

This will give you a split with a Bass sound on the lower half of the keyboard
and a Piano on the upper half.