General MIDI 1 made great strides in the music industry by providing a platform for compatibility between device manufacturers and content providers. Still, many manufacturers felt there needed to be additional functionality. General MIDI 2 (GM2) is a group of extensions made to General MIDI 1, which increases both the number of available sounds and the amount of control available for sound editing and musical performance. All GM2 devices are also fully compatible with General MIDI 1.
To support these new GM2 features, the MIDI specification has been extended with numerous new messages. Portions of the MIDI Specification which have been enhanced include MIDI Tuning, Controllers, RPNs, and Universal System Exclusive Messages. Of particular significance are the new Universal System Exclusive Messages, including Controller Destination Setting, Key-Based Instrument Controllers, Global Parameter Control, and Master Fine/Coarse Tuning.
In February 2007 a new version of the General MIDI 2 Specification document was made available, reflecting a change to the specification mandated by this AMEI/MMA approved Recommended Practice:
- RP-044: Adds a recommended Mod Depth Range RPN Response (+/- 600 cents) to GM2 devices. This RP does not affect SP-MIDI devices which refer to GM2 for some definitions..
In September 2003 a new version of the General MIDI 2 Specification document was made available, reflecting changes to the specification mandated by two AMEI/MMA approved Recommended Practices:
- RP-036: Sets a default Pan Curve for future AMEI/MMA specifications (equivalent to the Pan Curve defined in GML and DLS) and amends GM2 to include this curve.
- RP-037: Adds a recommendation that GM2 devices support the MIDI Tuning Extension "Scale/Octave Tuning Real Time One-Byte form" message.
Summary of GM2 Requirements
GENERAL REQUIREMENTS Number of Notes: 32 simultaneous notes MIDI Channels: 16 - Simultaneous Melodic Instruments = up to 16 (all Channels) - Simultaneous Percussion Kits = up to 2 (Channel 10/11) SUPPORTED CONTROL CHANGE MESSAGES (Some Optional) - Bank Select (cc#0/32) - Modulation Depth (cc#1) - Portamento Time (cc#5) - Channel Volume (cc#7) - Pan (cc#10) - Expression (cc#11) - Hold1 (Damper) (cc#64) - Portamento ON/OFF (cc#65) - Sostenuto (cc#66) - Soft (cc#67) - Filter Resonance (Timbre/Harmonic Intensity) (cc#71) - Release Time (cc#72) - Attack time (cc#73) - Brightness (cc#74) - Decay Time (cc#75) (new message) - Vibrato Rate (cc#76) (new message) - Vibrato Depth (cc#77) (new message) - Vibrato Delay (cc#78) (new message) - Reverb Send Level (cc#91) - Chorus Send Level (cc#93) - Data Entry (cc#6/38) - RPN LSB/MSB (cc#100/101) SUPPORTED RPNs (Registered Parameter Numbers) - Pitch Bend Sensitivity - Channel Fine Tune - Channel Coarse Tune - Modulation Depth Range (Vibrato Depth Range) - RPN NULL SUPPORTED UNIVERSAL SYSTEM EXCLUSIVE MESSAGES - Master Volume - Master Fine Tuning - Master Coarse Tuning - Reverb Type - Reverb Time - Chorus Type - Chorus Mod Rate - Chorus Mod Depth - Chorus Feedback - Chorus Send to Reverb - Controller Destination Setting - Scale/Octave Tuning Adjust - Key-Based Instrument Controllers - GM2 System On GM 2 INSTRUMENT SOUND SET GM 2 PERCUSSION SOUND SET
For complete details on GM2 features and MIDI message syntax, please consult the General MIDI Level 2 Specification (see below to order).
Developers of GM2 compatible devices or content are urged to consult the GM1 Developer Guidelines (included in the Complete MIDI 1.0Specification) which describe recommendations for content producers and device makers to insure improved compatibility among GM products.
The GM2 Logo was created to insure consumer recognition for products that meet the General MIDI 2 Specification. The GM Logos are the property of the MMA and AMEI and must be used in accordance with guidelines established to insure the value of the GM Logos for our members and for the consumer.
See updates at General MIDI LEVEL 2 Specification