Dmaj7#5

Construction

Built from these intervals: 1-3-#5-7.

This combines an augmented triad (1-3-#5) with a major 7th -- brightness upon brightness. The #5 pushes the 5th up a half step, creating an upward-reaching quality. The 7 adds its characteristic half-step-below-root tension. The augmented triad at the core is symmetrical -- three major thirds dividing the octave equally, so only four unique augmented triads exist. Every interval in this chord leans bright and unresolved.

Harmonic Function

In Roman numeral analysis (uppercase = major, lowercase = minor):

• bIIImaj7#5 in minor keys -- bIII is the chord built on the lowered third degree, and in harmonic minor (the minor scale with a raised 7th degree) this chord appears naturally; building a seventh chord on that degree produces 1-3-#5-7 directly
• Imaj7#5 -- a chromatic tonic (chromatic meaning outside the key's natural notes) with a Lydian augmented character; Lydian augmented is the name of the mode that pairs with this chord, bright but never truly at rest
• Color chord -- implies the Lydian augmented mode (the third mode of melodic minor, which is the minor scale with raised 6th and 7th degrees), used as a color chord in jazz

This chord rarely functions as a stable tonic. Its brightness creates forward motion even when technically "home."

Character

Luminous and ethereal. The #5 lifts the maj7 into suspended, almost weightless territory -- this chord floats rather than grounds. Compare to maj7 (1-3-5-7): the natural 5 provides stability, while the #5 removes it. That single half-step alteration transforms sophistication into something otherworldly. This is the sound of impressionist harmony and jazz that prioritizes color over function.

Related Sounds

These chords share closely related structures -- each modifies one or two intervals:

• maj7 (1-3-5-7) -- natural 5th, the stable parent chord
• aug (1-3-#5) -- the augmented triad inside, without the 7th
• 7#5 (1-3-#5-b7) -- dominant version, the b7 replaces the major 7th and adds dominant tension
• Lydian augmented mode -- the third mode of melodic minor, the scale that contains every tone of this chord

Voice Leading

Voice leading tracks how individual notes move from one chord to the next. The #5 creates upward-moving voice leading even from a tonic position. This built-in instability means the chord always suggests motion.

• Imaj7#5 to IVmaj7: The #5 moves up a half step to the 3 of IV. The 3 of I holds as the 7 of IV. The #5 resolving upward by half step is the most characteristic move.
• Imaj7#5 to ii7: The #5 moves up a half step to the 5 of ii. The 7 moves down to the root or 5 of ii. An unexpected but smooth connection that begins ii-V motion.
• bIIImaj7#5 to iiø7 (half-diminished -- minor 7th with a b5): In a minor key, natural voice leading from harmonic minor harmony. The #5 of bIII moves up a half step to the root of ii, and the 7 of bIII moves to the b7 of ii.

These movements apply in any key -- the intervals are the same regardless of root.

Practice Seeds

Brightness comparison. Play maj7, then maj7#5. Hear how the #5 adds another layer of brightness -- already luminous becomes ethereal. One half step on the 5th changes the entire character.

Find the augmented triad. Arpeggiate 1-3-#5 within the chord, then add the 7. Understand the augmented foundation that creates the floating quality.

Lydian augmented connection. Play maj7#5, then the Lydian augmented scale -- the third mode of melodic minor (start on the b3 of any melodic minor scale). Hear the scale inside the chord; the modal pairing explains the chord's character.

Chromatic color. Use maj7#5 as a passing chord between two stable maj7 voicings. Experience its ethereal quality in context -- not a destination, but a shimmer along the way.