F7#5

Construction

Built from these intervals: 1-3-#5-b7.

The 3 drives dominant function, and the b7 creates the restless pull toward resolution. The #5 raises the natural 5th by a half step, producing an augmented triad (1-3-#5) underneath the b7. Dom7 with the 5th raised a half step -- an alteration that trades the grounded natural 5th for upward-reaching tension. The result is a chord that is both bright from the augmented triad and tense from the dominant seventh structure.

Harmonic Function

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

• V7#5 -- altered dominant resolving to I. The #5 adds upward-reaching tension that standard V7 lacks, and its half-step ascent into the 3rd of I is the signature resolution.
• Whole tone dominant -- all four notes belong to the whole tone scale (a six-note scale built entirely from whole steps, with no half-step pull), accounting for four of its six pitches. This gives the chord an impressionistic, symmetrical color.
• Secondary dominant -- a technique where any major chord can be approached by its own V7#5, temporarily borrowing augmented brightness to intensify the resolution. The #5 creates a chromatic approach tone that steps up into the target chord's 3rd.

Character

Bright and restless. As a member of the altered dominant family, the augmented 5th gives this chord an expansive, reaching quality -- it stretches upward where 7b5 compresses inward. Compare to 7b5: both alter the 5th of dom7, but 7#5 raises it (augmented, ascending energy) while 7b5 lowers it (diminished, sliding tension). This is the sound of impressionistic jazz -- dominants that shimmer and glow rather than grind. The whole tone connection explains the floating, dreamlike quality.

Related Sounds

These chords share the dominant core -- each changes one element:

• aug (1-3-#5) -- the augmented triad inside, without the b7's dominant pull.
• 7 (1-3-5-b7) -- natural 5th, more grounded and conventional dominant sound; the parent chord.
• 7b5 (1-3-b5-b7) -- lowered 5th instead, chromatic sliding character rather than augmented brightness.
• 7(#5,#9) (1-3-#5-b7-#9) -- adds the #9 on top for a fully altered, aggressive sound.
• Pairs with the whole tone scale, which shares four of six notes with this chord.

Voice Leading

Voice leading tracks how individual notes move from one chord to the next. The #5 naturally resolves upward by half step, creating distinctive ascending voice leading that sets this chord apart from other dominants.

• V7#5 to I: The #5 moves up a half step to the 3 of I -- this chord's signature resolution. The 3 of V moves up a half step to the root of I. The b7 moves down a half step to the 3 of I.
• V7#5 to Imaj7: The #5 moves up a half step to the 3 of I. The b7 moves down a half step to the 3 of I. The 3 of V holds as the 7 of Imaj7 -- a common tone that smooths the transition.
• ii7 to V7#5 to Imaj7: The root of ii moves up a half step to become the #5 of V, then the #5 moves up another half step to the 3 of I -- a chromatic ascent through the altered dominant that the basic ii-V-I cannot produce.

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

Practice Seeds

Upward pull. Play V7#5 and resolve to I, listening for the #5 moving up a half step to the 3. Internalize this ascending tendency -- it is what distinguishes 7#5 from every other dominant alteration.

Find the augmented triad. Isolate the 1-3-#5 inside the chord, then add the b7. Hear how the b7 transforms a floating augmented triad into a dominant chord that demands resolution.

Whole tone connection. Play 7#5, then the whole tone scale from the same root (the scale built entirely from whole steps: 1-2-3-#4-#5-b7). Hear the scale implied by the chord -- four of the six whole tone pitches are already present, explaining the floating quality.

Compare fifth alterations. Play V7, V7b5, and V7#5 in sequence, each resolving to I. Distinguish the three different dominant colors -- natural, diminished, augmented -- and how each changes the character of resolution.