Nrpn/Rpns; Troubleshooting - M-Audio Session KeyStudio User Manual

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NRPN/RPNs

Non-registered parameter numbers (NRPN's) are device-speciﬁc messages that enable you to control synths and sound modules via MIDI. The

MIDI speciﬁcation deﬁnes open parameter numbers to allow manufacturers to specify their own controllers. The more common of these are

registered by the MIDI Manufacturer's Association and are now part of the MIDI speciﬁcation (hence the term Registered Parameter Numbers

– RPN's). (See Appendix B) 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 for 16,384 values in total.

MIDI controllers 98 and 99 represent the NRPN LSB and MSB respectively, while 100 and 101 represent the RPN LSB and MSB messages (see

the MIDI controllers list in Appendix B). 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 NRPN's is usually given in the user's manual of any device that receives NRPN messages. It is always necessary that the NRPN MSB and

LSB be sent together. Both will be speciﬁed in the device's manual.

ession KeyStudio has been tested in a wide range of systems and operating conditions. However, there are virtually limitless numbers of

operating scenarios, any of which could affect your system's performance. Though this section cannot cover all possible situations you

may encounter, we would like to offer some suggestions for dealing with possible problems. If you are still not able to ﬁnd the answer you are

looking for, please feel free to contact M-Audio technical support for further assistance.

Problem 1: My KeyStudio keyboard suddenly stopped working after having performed ﬁne since installation.

Solution 1: Close any music applications you are using, switch the KeyStudio off, and restart your computer. Once your computer has

completely restarted, switch the KeyStudio back on.

Problem 2: I have connected a sustain pedal to my M-Audio keyboard, but its function is reversed.

Solution 2: The polarity of the sustain pedal is calculated by the keyboard when it is powered up. On power up, the sustain pedal is

assumed to be in the OFF position. If you want the sustain pedal to be off when it is not pressed, make sure the pedal is not pressed when

you power up. Also check to see if there is a polarity switch on your foot pedal. It is possible to use this switch to change foot pedal polarity

as well. Another way to reverse the sustain pedal's polarity is to keep it pushed while powering on your KeyStudio keyboard.

Problem 3: When I press a key, or attempt to monitor my microphone or instrument input, there is a noticeable delay before I hear

any sound.

Solution 3: This delay is known as latency, and latency can be adjusted by changing the buffer size setting in your M-Audio Micro control

panel. The goal is to set the buffer size as low as possible without experiencing artifacts in the audio. Faster computers generally allow for

smaller buffer size settings, and thus less latency. If there is a large delay between what you play on the keyboard, and what you hear from

your virtual instrument in Session, click Options > Audio Hardware > ASIO Settings > Latency, and drag the slider downwards.

Session KeyStudio User Guide

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