Alesis QS6.1 Reference Manual

Appendix B: MIDI Supplement

SYSTEM COMMON MESSAGES

Intended for all units in a system, some of these MIDI messages are:

Song Position Pointer.

This indicates how many ÒMIDI beatsÓ (normally a 16th note) have elapsed since a piece started (up to 16,384 total beats). It is primarily used to allow different sequencers and drum machines to auto-locate to each other so that if you start one sequencer, the other device will automatically jump to the same place in the song, whereupon both continue on together.

System Exclusive.

This message (called Sys-ex for short) is considered ÒexclusiveÓ because different manufacturers send and receive data over MIDI which is intended only for that manufacturerÕs equipment. Example: Sending a QS6.1 message to an

Alesis DMPro Drum Module wonÕt do anything, but the message will be understood by another QS6.1. This data often contains information about individual instrument programs.

Timing Clock.

A master tempo source (such as a sequencer) emits 24 timing messages (clocks) per quarter note. Each device synchronized to the sequencer advances by 1/24th of a quarter note when it receives the clock message, thus keeping units in sync after theyÕve both started at the same time. Many devices subdivide this clock signal internally for higher resolution (e.g., 96 pulses per quarter note).

Start.

Signals all rhythmically-based units when to start playing.

Stop.

Signals all rhythmically-based units when to stop playing.

Continue.

Unlike a Start command, which re-starts a sequencer or drum machine from the beginning of a song each time it occurs, sending a Continue message after a

Stop command will re-start units from where they were when they stopped.

G

ENERAL

MIDI

General MIDI (GM) is an extension of the MIDI standard designed to meet the demands of the ever-growing multimedia industry, and to make simple the act of playing commercially-produced MIDI sequences. The GM standard utilizes all 16 channels available in MIDI. The QS6.1 is a perfect General MIDI companion, since its

Mix Mode uses 16 channels. Although many channels are commonly used for specific types of instruments (Example: Channel 1 is usually piano, channel 2 is usually bass, etc.), channel 10 is always used for drums.

General MIDI also standardizes the placement of sound types in a sound deviceÕs memory bank. The QS6.1Õs GenMIDI Bank is designed specifically for General MIDI, and organizes its sounds according to the GM specification. This means that when a sequencer sends a MIDI program change message that is supposed to call up a particular sound, the correct sound will be there on the QS6.1, even if the composer of the sequence used a different sound device. The Programs in the GenMIDI Bank use the standard General MIDI names, which is handy because many commerciallyavailable GM sequences have the names of the instruments used in the songs stored with the track data.

170 QS6.1 Reference Manual

Appendix B Ñ MIDI Supplement

There are three MIDI registered parameter numbers (RPNs) which the QS6.1 will recognize in Mix Play Mode when General MIDI Mode is enabled. These are:

¥

MIDI Registered Parameter 0

(Pitch Bend Sensitivity): This will directly affect the Pitch Wheel Range parameter of all four Sounds of the Program on the received MIDI Channel of the Mix. If the Channel which received the RPN is selected using the [

▲

PAGE] and [PAGE ] buttons, the word ÒEDITEDÓ will appear next to the word ÒMIXPROGÓ in the lower part of the display. However, if you are viewing the Pitch Wheel Range parameter in the display (Mix Program

Edit Mode, Pitch Function, Page 4) when the RPN arrives, the display will not be updated to reflect the new setting. But if you go to another Page or Function and then return, the display will reflect the updated setting.

¥

MIDI Registered Parameter 1

(Fine Tune): This will directly effect the Pitch

Detune parameter of all four Sounds of the Program on the received MIDI

Channel of the Mix. Also, when this RPN is received, the QS6.1 will automatically make sure that all four Sounds of the Program have their Detune

Type parameter set to ÒNormalÓ (Program Edit Mode, Pitch Function, Page 3). If the Channel which received the RPN is selected using the [

▲

PAGE] and

[PAGE ] buttons, the word ÒEDITEDÓ will appear next to the word

ÒMIXPROGÓ in the lower part of the display. However, if you are viewing the

Detune Amount parameter in the display (Program Edit Mode, Pitch Function,

Page 2) when the RPN arrives, the display will not be updated to reflect the new setting. But if you go to another Page or Function and then return, the display will reflect the updated setting.

¥

MIDI Registered Parameter 2

(Coarse Tune):This will directly effect the Pitch

Semitone parameter of all four Sounds of the Program on the received MIDI

[

Channel of the Mix. If the Channel which received the RPN is selected using the

▲

PAGE

] and [PAGE ] buttons, the word ÒEDITEDÓ will appear next to the word ÒMIXPROGÓ in the lower part of the display. However, if you are viewing the Tune Semitone parameter in the display (Program Edit Mode, Pitch Function,

Page 1) when the RPN arrives, the display will not be updated to reflect the new setting. But if you go to another Page or Function and then return, the display will reflect the new setting.

(Portions of this appendix are abridged versions of material from Power Sequencing

with Master Tracks Pro/Pro 4 and The Complete Guide to the Alesis HR-16 and MMT-8 , copyright 1990 and 1989 respectively by AMSCO Publications, and are adapted with permission.)

QS6.1 Reference Manual 171