Eb9#5

Construction

Built from these intervals: 1-3-#5-b7-9.

The 3 and b7 form the tritone (the interval of six half steps) at the dominant core. The #5 raises the natural 5 by a half step -- an alteration (a chord tone raised from its natural position) -- creating an augmented triad (1-3-#5) underneath the b7 and 9. 9#5 is 7#5 with an added 9. Five of the six whole tone scale pitches are present (1, 9, 3, #5, b7), giving the chord a floating, symmetrical quality with ascending energy from the #5.

Harmonic Function

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

• V9#5 -- altered dominant resolving to I, the #5 pulling upward while the 9 adds richness beyond the parent 7#5.
• Whole tone dominant -- five of six whole tone pitches present, strongly implying the whole tone scale's impressionistic color.
• Augmented dominant extension -- the 9 softens the augmented triad's edge, making this a gentler, more sophisticated alternative to 7#5 in jazz progressions where V resolves to I or i.

Character

Bright and expansive. As a member of the altered dominant family, the #5 reaches upward while the 9 fills the chord with warmth. Compare to 9b5: both are altered dominant 9th chords, but 9#5 stretches outward (the #5 raises, creating augmented brightness) while 9b5 compresses inward (the b5 lowers, creating sliding tension). This is the sound of jazz dominants that glow and shimmer rather than grind and drive -- impressionistic color with just enough pull to resolve.

Related Sounds

These chords share the dominant core -- each changes the 5th or the 9th:

• 7#5 (1-3-#5-b7) -- the parent chord, without the 9th's warmth; more stark augmented dominant
• 9 (1-3-5-b7-9) -- natural 5, standard dominant 9th without the augmented brightness
• 9b5 (1-3-b5-b7-9) -- b5 instead of #5, different altered color with inward, sliding character
• 7(#5,#9) (1-3-#5-b7-#9) -- #9 instead of natural 9, more aggressive with the added major/minor clash
• Pairs with the whole tone scale, which shares five of six notes with this chord

Voice Leading

Voice leading tracks how individual notes move from one chord to the next. The #5 resolves upward by half step and the 9 resolves downward by step, creating a natural fanning motion in the upper voices.

• V9#5 to Imaj7: The #5 moves up a half step to the 3 of I -- this chord's signature resolution. The 3 of V holds as the 7 of Imaj7 (common tone). The b7 moves down a half step to the 3 of I. The 9 descends by step to the 5 of I.
• V9#5 to I6: The #5 moves up a half step to the 3 of I. The 9 of V holds as the 6 of I6 -- a common tone that gives this resolution its elegance.
• ii9 to V9#5 to Imaj7: The 5 of ii holds as the 9 of V (common tone), then descends to the 5 of I. The 9 of ii moves down a half step to become the #5 of V, which resolves up a half step to the 3 of I -- chromatic neighbor-tone motion through the altered dominant.

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

Practice Seeds

Upward resolution. Play V9#5, resolving the #5 upward a half step to the 3rd of I. Feel the augmented 5th's natural ascending direction -- this is what makes the chord reach rather than compress.

Whole tone connection. Play 9#5, then the whole tone scale from the same root. Hear the scale inside the chord -- five of six pitches align. This chord-scale match explains the floating, dreamlike quality.

Compare altered ninths. Play 9, 9b5, and 9#5 in sequence on the same root. Distinguish the three dominant 9th colors -- natural 5 (grounded), b5 (sliding inward), #5 (reaching outward) -- and how each alteration creates a fundamentally different character.

Extended ii-V-I. Play ii9 to V9#5 to Imaj7, listening for the chromatic neighbor-tone motion: the 9 of ii becomes the #5 of V, then resolves back up to the 3rd of I. This is how the altered dominant adds impressionistic color to a standard progression.