G♭0 — 23.125 Hz
G♭0 (G-flat 0) is 23.125 Hz in standard equal temperament at A=440 Hz. It is MIDI note number 18. This is the flat spelling of this pitch — see also F♯0.
G♭ is the tonic of G♭ major (6 flats) and is the enharmonic twin of F♯ major. G♭ major is the only major key with 6 flats.
G♭0 Frequency in All Tuning Systems
| Temperament | Frequency (Hz) | Cents from Equal | Common Usage |
|---|---|---|---|
| Equal Temperament | 23.125 Hz | 0.00 | Modern standard; piano, fretted instruments |
| Pythagorean Tuning | 23.203 Hz | +5.83 | Medieval/early music; string ensemble open fifths |
| Just / Pure | 22.994 Hz | -9.84 | A cappella vocal, barbershop, Renaissance |
| Meantone 1/3 Comma | 22.943 Hz | -13.68 | Renaissance vocal music in minor keys |
| Meantone 1/4 Comma | 22.988 Hz | -10.29 | Renaissance keyboard, early Baroque organ |
| 1/6 SC - Attenuated | 23.033 Hz | -6.90 | Baroque orchestral ensemble compromise |
| Kellner's Bach | 23.114 Hz | -0.82 | Bach keyboard reconstruction |
| Kirnberger III | 23.138 Hz | +0.97 | Classical-era keyboard, keys near C major |
| Vallotti | 23.125 Hz | 0.00 | Baroque/Classical orchestral tuning |
| Werckmeister III | 23.125 Hz | 0.00 | Baroque keyboard; Bach contemporaries |
| Werckmeister IV | 23.020 Hz | -7.88 | Baroque keyboard, strong key contrast |
| Werckmeister V | 23.125 Hz | 0.00 | Specialized Baroque keyboard |
Positive cents = sharper than equal temperament. Negative cents = flatter. 100 cents = 1 semitone.
G♭0 at Different Concert Pitches
The same note varies in frequency depending on the concert pitch standard used by your ensemble.
| Concert Pitch | Frequency (Hz) | Common Usage |
|---|---|---|
| A = 440 Hz (ISO standard) | 23.125 Hz | US, UK, and most modern ensembles worldwide |
| A = 442 Hz | 23.230 Hz | Many European orchestras; France, Germany |
| A = 443 Hz | 23.282 Hz | Berlin Philharmonic; some US orchestras |
| A = 432 Hz | 22.704 Hz | Alternative tuning; Baroque revival |
| A = 415 Hz (Baroque) | 21.811 Hz | Historically-informed Baroque performance |
f = f_at_A440 × (concert_pitch / 440)
G♭0 and F♯0 — Enharmonic Equivalents
G♭0 and F♯0 are enharmonic equivalents — they sound identical at 23.125 Hz but are written differently depending on the musical context.
When to Write G♭0
G♭ is the tonic of G♭ major (6 flats) and is the enharmonic twin of F♯ major. G♭ major is the only major key with 6 flats.
Composers choose G♭ when writing in flat-side keys (D♭ major, G♭ major). In descending chromatic passages within flat keys, G♭ is the theoretically correct spelling. G♭ major and F♯ major sound identical but use different notation; the choice depends on the surrounding harmonic context.
Major scales containing G♭0: G♭ major (tonic), D♭ major (4th), C♭ major (5th).
Minor scales containing G♭0: E♭ minor (3rd), B♭ minor (6th).
G♭0 in Instrument Literature
Wind and brass ensembles occasionally encounter G♭ in heavily flatted keys. Harpists may prefer G♭ major over F♯ major because harp pedal notation maps more naturally to flats. Flute players in orchestral literature sometimes see G♭ in modulating passages.
In fixed-do solfège, G♭ is sung as "se" (♭5). In G♭ major with moveable do, it is "do" (the tonic).
How F♯0 Differs in Context
While F♯0 sounds identical to G♭0, it belongs to a different set of keys and carries different harmonic implications.
F♯0: F♯ is the first sharp added to a key signature (G major) and appears in every sharp key. It is the tonic of F♯ major (6 sharps).
Major scales: G major (7th / leading tone), D major (3rd), A major (6th), E major (2nd), B major (5th), F♯ major (tonic).
Minor scales: E minor (2nd), B minor (5th), F♯ minor (tonic), C♯ minor (4th), D minor (3rd, melodic ascending).
F♯ is extremely common for string instruments — violinists encounter it in G major (1 sharp), their most natural key after C. Guitarists play F♯ regularly in keys like G, D, and E major. Keyboard players see it as the first sharp in the key-signature order.
Enharmonic equivalents share the same frequency in equal temperament. In historical temperaments like Pythagorean or meantone, they may differ slightly — see the temperament comparison table above for this note's exact deviations.
Why G♭0 Varies Across Tuning Systems
G♭0 shows a maximum deviation of -13.68 cents in Meantone 1/3 Comma compared to equal temperament. This 14-cent difference reflects how different tuning philosophies prioritize interval purity over equal distribution.
In Meantone 1/3 Comma, G♭0 is tuned flatter than equal temperament, reflecting this system's approach to distributing the Pythagorean comma across the chromatic scale.
2 of the 15 non-equal temperaments deviate by more than 10 cents for G♭0, making this note one where tuning system choice has a meaningful impact on pitch.
G♭0 Across All Tuning Systems
Explore how G♭0 is tuned in each historical temperament system. Each tuning system gives G♭0 a slightly different frequency, affecting the harmonic character of chords and melodies.
G♭0 in Historical Temperament Systems
Explore how G♭0 (23.125 Hz in equal temperament) is tuned in each of the 15 historical non-equal temperament systems. Each system places G♭0 at a slightly different frequency based on its mathematical basis.
Tune G♭0 with precision — Get Tunable.
Tunable supports 15+ tuning systems including equal temperament, Pythagorean, just intonation, and historical well-temperaments. See exact Hz values in real-time as you play.
