M-Audio 99004139310 manual Fine

Oxygen Series User Guide  6

16,384 step resolution through combined Coarse and Fine messages

Most assignable MIDI controls, including those on your Oxygen series keyboard, operate with a resolution of 128 steps. Standard MIDI CC messages that can be used universally between different MIDI devices are also limited to a resolution of 128 steps. However, the RPN/NRPN concept allows for a resolution of 16,384 steps by combining two 7-bit MIDI messages into a 14-bit message (coarse + fine).

Hardware controller knobs or sliders that take advantage of the full 14-bit RPN/NRPN resolution are very uncommon. To illustrate the concept and make the purpose of RPN/NRPN Coarse and Fine messages easier to understand, we included a graphic describing how such a 14-bit RPN/NRPN control would operate (not supported by Oxygen Series keyboards):

16,384

3

127

99

88

77

66

Fine

55
44
33	16,384
2

1

0

2

127

99

Coarse8

8

77

66Fine

55
44
33
2
1
0	0
1

127

99

88

77

66

55

44

33

2

1

0

Fine

0

The RPN/NRPN coarse message divides the range of 16384 steps into 128 segments and activates them by sending each segment's first value, while the RPN/NRPN fine message provides the 128 steps of resolution contained in each of these segments.