G♭4 : 369.994 Hz

G♭4 and F♯4: Enharmonic Equivalents

G♭4 and F♯4 are enharmonic equivalents, they sound identical at 369.994 Hz but are written differently depending on the musical context.

When to Write G♭4

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.

G♭4 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♯4 Differs in Context

While F♯4 sounds identical to G♭4, it belongs to a different set of keys and carries different harmonic implications.

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.