M-Audio Keyboard Controller Series User's Guide download pdf (Page 49)

Chapter 7: MIDI Messages Defined

Axiom User Guide

can select any of a possible 16,384 banks. Each bank can in turn contain 128 possible sounds selected via a

separate program change MIDI message. This enables a user to theoretically recall over two million programs

directly, using only MIDI commands. However, most devices only use a few different banks, and you can

often ignore the LSB message.

You will find many MIDI devices respond to program change commands and many are organized according

to the GM listing. In General MIDI devices, different sounds are organized in the same way from device to de-

vice. Piano sounds are in their particular place, string sounds are in their place, drum sounds are in their place,

and so on. All GM devices (both hardware and software sound modules) are clearly labeled as such, so you

know that their sounds are organized in the General MIDI structure. When a GM device receives a MIDI pro-

gram change, it calls up a type of sound that you expect from the GM sound set. All non-GM MIDI sound

modules call up unique sounds from their memory upon receiving MIDI program changes. Since the sounds

in a non-GM device are not arranged in a particular order, you need to take a look at the device itself to see

which sound you want and at which location in the memory it resides. Many VST instruments such as Native

Instruments’ FM7 or the synth modules in Propellerheads Reason are non-GM devices.

You can send Program Change, Bank LSB and Bank MSB messages directly from Axiom.

Please consult the documentation for your sound module, DAW or software instrument for further

information.

RPN/NRPNs

Overview

RPN stands for “Registered Parameter Number” and NRPN stands for “Non-Registered Parameter Number.”

Non-registered parameter numbers (NRPNs) are device-specific messages that enable you to control specific

synthesizer or sound module parameters via MIDI that are not accessible via standard MIDI CC's. The MIDI

specification defines open parameter numbers to allow manufacturers to specify their own NRPN controllers.

The more common of these are registered by the MIDI Manufacturers Association and are now part of the

MIDI specification, hence the term Registered Parameter Numbers or RPNs. See Appendix A, “Standard MIDI

Control Numbers (MIDI CC’s).” Each NRPN/RPN has an associated 2-byte number. The two bytes allow for

128 values each. An RPN or NRPN message is made up of two parts: The MSB and the LSB message. Both of

these messages together constitute an RPN or NRPN command. This allows 16,384 values in total. MIDI con-

trollers 98 and 99 represent the NRPN LSB and MSB respectively, while 100 and 101 represent the RPN LSB and

MSB messages.

To transmit an NRPN/RPN message, these LSB and MSB controller messages are sent along with their user

specified values. A further controller message and value needs to be sent to specify the (coarse or fine) value

adjustment. This is specified by controller number 6 (data entry) for coarse adjustments or number 38 for fine

adjustments.

A list of NRPNs is usually included in the documentation for any NRPN compatible device. It is always neces-

sary that the NRPN MSB and LSB be sent together. Both will be specified in its manual, but typically only in

Hexadecimal format. If this is the case, see Appendix E, “Hexadecimal Conversion Chart” for help translating

the value to decimal.

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M-Audio Keyboard Controller Series User's Guide Page 49