B♭ Diminished Scale (Half-Whole)

Notes in the B♭ Diminished Scale (Half-Whole)

Interval Pattern

Chords Built on Scale Degrees

Key Signature

2 ♭ — The B♭ key signature uses B♭, E♭.

B♭ Diminished Scale (Half-Whole) in Practice

The B♭ Diminished Scale (Half-Whole) uses the key signature of 2 flats (B♭, E♭). Bb major has two flats (Bb, Eb) and is extremely common in jazz and wind ensemble music. It is the home key for Bb instruments such as the trumpet and tenor saxophone. On guitar, B♭ positions offer comfortable transposing instrument keys for this scale.

The half-whole diminished scale alternates half and whole steps, creating an 8-note symmetrical scale ideal for dominant chord improvisation and tension-building in jazz. When played starting on B♭, the 8 notes are B♭, B, D♭, D, E, F, G, A♭. In this key the signature has 2 flats (B♭, E♭). Bb is the concert-pitch key when Bb instruments (trumpet, clarinet, tenor sax) play in their native C, making it the most common jazz and band key. Jazz standards in Bb are ubiquitous — tunes like "Autumn Leaves" and "All Blues" sit naturally for horn sections, and the key is a default for jam sessions.

Tuning Frequencies Across Temperaments

Frequencies shown at A=440 Hz. View full temperament data for any note.

Related Scales

Transposing Instruments: B♭ Diminished Scale (Half-Whole)

B♭ is a natural key for B♭ instruments (trumpet, clarinet, tenor sax), which sound a major second lower than written. B♭ instruments reading in C produce B♭ concert pitch. E♭ instruments (alto sax, baritone sax) reading in B♭ sound a major sixth lower.