General MIDI 1 made great strides in the music industry by providing a platform for compatibility between device manufacturers and content providers. Still, by 1999 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.

New MIDI Messages

To support new features in GM2 devices, the MIDI specification was also extended with numerous new  control messages, 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.

General MIDI is an industry-wide set of specifications for sound sources that allow music data to be created regardless of manufacturer or specific models. General MIDI defines the minimum number of voices that should be supported, the MIDI messages that should be recognized, which sounds correspond to which Program Change numbers, and the layout of rhythm sounds on the keyboard. The General MIDI logo on a sound source indicates compatibility with song data which also carries the General MIDI logo.General MIDI is an industry-wide set of specifications for sound sources that allow music data to be created regardless of manufacturer or specific models. General MIDI defines the minimum number of voices that should be supported, the MIDI messages that should be recognized, which sounds correspond to which Program Change numbers, and the layout of rhythm sounds on the keyboard. The General MIDI logo on a sound source indicates compatibility with song data which also carries the General MIDI logo.

GM2 (General MIDI System Level 2) is a set of standards for editing voices not covered by GM1. GM2 also defines the operation specifications of effects and other elements in detail, and enables more sophisticated performance expression and greater compatibility, by expanding range of voices.