If you have been around a keyboard or digital piano within the past few years, you probably have heard references to General MIDI and General MIDI 2. How does that fit in with MIDI? Is there a difference, and should you care? The answer depends on if you plan to share your MIDI work with other musicians or if you will be saving the data just for your own use. If it is the latter, then you really can save the file in any format you want since you will be the only person using the file.

General MIDI Level 1 Instrument Patch Map In the percussion sounds, each will be located at the same note location. For example, note number 35 would be the bass drum. When you play note 35 on MIDI channel 10, and you are in GM mode, you will always hear a bass drum. General MIDI Level 1 Instrument Patch Map. Note: While GM1 does not define the actual characteristics of any sounds, the names in parentheses after each of the synth leads, pads, and sound effects are, in particular, intended only as guides). PC# Instrument Name: 1. Acoustic Grand Piano: 2. Bright Acoustic Piano: 3. Electric Grand Piano: 4.

If you would like to take a MIDI file of one of your performances and share it with others, then you will want to follow the basic rules of General MIDI, usually referred to as GM or GM2, which is short for General MIDI 2.

Just about any keyboard, digital piano, or organ made over the past couple of years will be GM aware, and more than likely will be GM2 capable. To verify that your keyboard supports GM or GM2 first, look in your owner’s manual. You should also be able to find the GM or GM2 logos on your keyboard.

Both GM and GM2 formats are nothing more than a standard that allows any piece of equipment displaying the GM or GM2 logo to understand and share data in those formats. That means if you record a song and you select an Acoustic Bass, Piano, and Standard Drum Set, you can expect the file to playback on any GM/GM2 instrument with the same instruments – Acoustic Bass, Piano, and Standard Drum Set. While those instruments’ sound quality may vary from vendor to vendor, you can expect them to be reasonably close.

General MIDI, created back in the 1980s, is still in use today. There are 128 instruments in the General MIDI patch map. The instruments are grouped into various instrument families.

General MIDI Level 1 Instrument Families

General MIDI Level 1 Instrument Patch Map

General Midi Level 1 Instrument Patch Map

In the percussion sounds, each will be located at the same note location. For example, note number 35 would be the bass drum. When you play note 35 on MIDI channel 10, and you are in GM mode, you will always hear a bass drum.

General MIDI Level 1 Percussion Key Map

Although you have access to 128 instruments in General MIDI mode, you will only have access to one drum kit, the standard drum kit.

This is a perfect lead-in for GM2 or General MIDI 2. Introduced in 1999 as an extension to the original GM format, GM2 allows both MIDI channels 10 and 11 for percussion parts along with the essential MIDI bank change command.

Let’s go back to the Bass Drum example. In General MIDI, we mentioned that you could only access the standard drum kit. You probably have multiple drum kits on your instrument. Depending on the type of music you are performing, selecting the correct drum kit can make or break the performance. To access a different drum kit, you need to issue a bank change command and the program number of the desired drum kit. In GM2 mode, nine drum kits are available.

GM2 Drum Kits

The same thing is true for your instrument patches. You will be able to select additional banks of instruments by using the bank select command. In GM2, the number of instruments you will have access to grows to 256 instruments compared to only 128 in GM mode. The additional instruments fall under the same instrument families found in GM. For example, in the piano family, you will find Detuned Electric Piano located in Bank 1 Program Number 5 and Detuned Electric Piano2 located in Bank 1 Program Number 6. This is in addition to the Electric Piano 1 and Electric Piano 2 piano offered in GM mode, located in Bank 0 in the same program number locations (5 and 6).

To summarize, GM2 files will offer a wider palette of sounds and supporting effects, along with additional control features allowing more editing of the final musical performance.

So what does all this sound like? Take a listen to a short sample of a jazz arrangement of Bach Prelude XV, which is a General MIDI format sequence using the instruments mentioned earlier, Acoustic Bass, Piano, and Standard Drum Set.

Since this file is saved in General MIDI format, it will play the correct instruments regardless of the manufacturer of the GM capable MIDI device it is played back on. That could be the sound card in your computer or your multi-thousand dollar keyboard. The only difference in the final listening experience will be the quality of the sampled instruments your MIDI device offers.

General MIDI (also known as GM or GM 1) is a standardized specification for electronic musical instruments that respond to MIDI messages. GM was developed by the American MIDI Manufacturers Association (MMA) and the Japan MIDI Standards Committee (JMSC) and first published in 1991. The official specification is available in English from the MMA, bound together with the MIDI 1.0 specification, and in Japanese from the Association of Musical Electronic Industry (AMEI).

GM imposes several requirements beyond the more abstract MIDI 1.0 specification. While MIDI 1.0 by itself provides a communications protocol which ensures that different instruments can interoperate at a fundamental level (e.g., that pressing keys on a MIDI keyboard will cause an attached MIDI sound module to play musical notes), GM goes further in two ways: it requires that all GM-compatible instruments meet a certain minimal set of features, such as being able to play at least 24 notes simultaneously (polyphony), and it attaches specific interpretations to many parameters and control messages which were left unspecified in the MIDI 1.0 spec, such as defining instrument sounds for each of the 128 possible program numbers.

GM ensures that playback of MIDI files sounds consistently between different devices compliant with the GM specification. Instrument selection in MIDI is done by assigning a 'Program Number': this assignment previously was arbitrary, while a specific instrument is attributed to each program number with GM.

The GM 1 specification was superseded by General MIDI 2 in 1999; however, GM 1 is still commonly used.^[1]

General MIDI 1 Requirements[edit]

Midi Instruments Online

To be GM 1 compatible, sound generating devices (keyboards, hardware or software synthesizers, sound cards) are required to meet the General MIDI System Level 1 performance specification:

Criterion	Requirement
Voices	Allow 24 voices to be available simultaneously for both melodic and percussive sounds (alternatively, allow 16 melodic and 8 percussive voices). All voices respond to note velocity.
Channels	Support all 16 channels simultaneously, each assignable to different instruments. Channel 10 is reserved for percussion. Support polyphony (multiple simultaneous notes) on each channel.
Instruments	Support a minimum of 128 MIDI Program Numbers (conforming to the GM 1 Instrument Patch Map) and 47 percussion sounds (conforming to the GM 1 Percussion Key Map).
Channel messages	Support for controller number 1, 7, 10, 11, 64, 100, 101, 121 and 123; support for channel pressure and pitch bend controllers.
Other messages	Respond to the data entry controller and the RPNs for fine and coarse tuning and pitch bend range, as well as all General MIDI Level 1 System Messages.

Parameter interpretations[edit]

GM Instruments must also obey the following conventions for program and controller events:

Program change events[edit]

In MIDI, the instrument sound or 'program' for each of the 16 possible MIDI channels is selected with the Program Change message, which has a Program Number parameter. The following table shows which instrument sound corresponds to each of the 128 possible Program Numbers for GM only. There are

General Midi Instrument Patch Map