How Many Sounds Are in the General MIDI Map?

The General MIDI (GM1) specification standardizes sound patch assignments so that MIDI files sound consistent across different hardware and software synthesizers. In total, the standard General MIDI sound set catalogs exactly 128 melodic instrument sounds—spanning both traditional acoustic and modern synthetic timbres—alongside a dedicated percussion map containing 47 distinct drum and percussion sounds. This standardized numbering system ensures that a MIDI command requesting a specific sound, such as an acoustic piano or a synthesizer lead, plays the correct instrument regardless of the manufacturer.

The 128 Melodic Instruments

The core General MIDI map defines 128 melodic program numbers (numbered 1 through 128, or 0 through 127 in zero-indexed software). These 128 sounds are evenly divided into 16 distinct instrument families, with each family containing eight related instruments:

• Piano (1–8): Acoustic grand pianos, bright pianos, electric grand pianos, honky-tonk, and various electric pianos.
• Chromatic Percussion (9–16): Celesta, glockenspiel, music box, vibraphone, marimba, xylophone, tubular bells, and dulcimer.
• Organ (17–24): Drawbar, percussive, rock, church, and reed organs, as well as accordion and harmonica.
• Guitar (25–32): Nylon-string, steel-string, jazz electric, clean electric, muted electric, overdriven, distorted, and guitar harmonics.
• Bass (33–40): Acoustic upright bass, finger-style electric, picked electric, fretless, slap basses, and synthesizer basses.
• Strings (41–48): Solo violin, viola, cello, contrabass, tremolo strings, pizzicato strings, orchestral harp, and timpani.
• Ensemble (49–56): String ensembles, synth strings, choir aahs, voice oohs, synth voice, and orchestra hits.
• Brass (57–64): Trumpet, trombone, tuba, muted trumpet, French horn, brass section, and synth brass variations.
• Reed (65–72): Soprano, alto, tenor, and baritone saxophones, oboe, English horn, bassoon, and clarinet.
• Pipe (73–80): Piccolo, flute, recorder, pan flute, blown bottle, shakuhachi, whistle, and ocarina.
• Synth Lead (81–88): Classic analog-style lead sounds, including square, sawtooth, calliope, chiffer, charang, voice, fifths, and bass-and-lead.
• Synth Pad (89–96): Ambient synthesizer textures such as new age, warm, polysynth, choir, bowed, metallic, halo, and sweep pads.
• Synth Effects (97–104): Atmospheric synthesis patches including rain, soundtrack, crystal, atmosphere, brightness, goblins, echoes, and sci-fi.
• Ethnic (105–112): Traditional acoustic world instruments such as sitar, banjo, shamisen, koto, kalimba, bagpipe, fiddle, and shanai.
• Percussive (113–120): Tinkle bell, agogo, steel drums, woodblock, taiko drum, melodic tom, synth drum, and reverse cymbal.
• Sound Effects (121–128): Real-world acoustic recordings and effects like guitar fret noise, breath noise, seashore, bird tweet, telephone ring, helicopter, applause, and gunshot.

The General MIDI Percussion Map

In addition to the 128 melodic sounds, General MIDI reserves MIDI Channel 10 exclusively for rhythm tracks. Rather than changing pitch across the keyboard, key numbers on Channel 10 trigger specific drum and percussion sounds. The GM standard catalogs 47 standardized percussion sounds, mapped from MIDI note 35 (Acoustic Bass Drum) through MIDI note 81 (Open Triangle). This set includes standard acoustic drum kit elements—such as kicks, snares, toms, hi-hats, and cymbals—as well as Latin and hand percussion like bongos, congas, timbales, and maracas.