General MIDI 1 Specification
Note: The GM1 specification was superceded in 1999 by the General MIDI 2 Specification which offers additional features and capabilities. However, GM1 remains a popular format for lower-cost synthesizers and is commonly used for music distributed as Standard MIDI Files.
GM1 Device Features
To be GM1 compatible, a GM1 sound generating device (keyboard, sound module, sound card, IC, software program or other product) must meet the General MIDI System Level 1 performance requirements outlined below, instantaneously upon demand, and without additional modification or adjustment/configuration by the user.
- Voices: A minimum of either 24 fully dynamically
allocated voices are available simultaneously for both melodic and
percussive sounds, or 16 dynamically allocated voices are available
for melody plus 8 for percussion. All voices respond to velocity.
Channels: All 16 MIDI Channels are supported. Each Channel can play a variable number of voices (polyphony). Each Channel can play a different instrument (sound/patch/timbre). Key-based percussion is always on MIDI Channel 10.
Instruments: A minimum of 16 simultaneous and different timbres playing various instruments. A minimum of 128 preset instruments (MIDI program numbers) conforming to the GM1 Instrument Patch Map and 47 percussion sounds which conform to the GM1 Percussion Key Map.
Channel Messages: Support for continuous controllers 1, 7, 10, 11, 64, 121 and 123; RPN #s 0, 1, 2; Channel Pressure, Pitch Bend.
Other Messages: Respond to the data entry controller and the RPNs for fine and course tuning and pitch bend range, as well as all General MIDI Level 1 System Messages.
Developer Information
The MMA's GM Developer Guidelines document (also included in the Complete MIDI 1.0Specification) describes additional recommendations and clarifications of the GM Specification for content producers and device makers, to insure improved compatibility among GM products.
The GM1 Logo was created to insure consumer recognition for products that meet the General MIDI Level 1 Specification. The GM Logo is the property of the MMA and AMEI and must be used in accordance with guidelines established to insure the value of the GM Logo for our members and for the consumer.