User guide

Chapter 7: MIDI Messages Defined
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Axiom User Guide
Combining Two MIDI CC Numbers for 16,384 Possible RPNs/NRPNs
A single MIDI CC provides 128 values or possible selections which is not enough to provide a sufficient num-
ber of unique RPN/NRPNs for all manufacturers of MIDI equipment. In order to make a large enough number
of RPN and NRPN messages available for use by the many manufacturers of MIDI devices, two specific MIDI
CC numbers (NRPN=98+99; RPN=100+101) are combined for RPN/NRPN selection. When combining two
MIDI CC numbers this way, the 128 possibilities of the first MIDI CC multiply with the 128 possibilities of the
second MIDI CC, resulting in 16384 unique possibilities - plenty of options for all manufacturers of MIDI
equipment.
You can think of this as a matrix of 128x128 options, each representing a unique identifier a manufacturer of
MIDI equipment may choose to use for selection of a specific parameter in their device. See the illustration be-
low.
0
0123456789
1
2
3
4
5
6
7
CC99
CC98
CC98
Value 5
CC99
Value 4
8
9
127
0
1
2
3
4
4
5
5
6
7
8
8
9
9
0
1
2
3
3
4
4
5
5
6
6
7
7
8
8
8
9
9
9
Two MIDI CCs
(98&99 or 100&101)
select an RPN/NRPN
for editing
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