The 7♭5#9 chord is one of the four most common altered seventh chords that you will see in music, especially in jazz. I cover the intervals in the 7♭5#9 chord, the notes in the D♭7♭5#9 chord, its resolution tendency and how to use the chord. Also, I have open and closed guitar chord voicings for the 7♭5#9 chord in the key of D♭, as well as 7♭5#9 with the ♭9 added.
The 7♭5#9 chord in detail
This chord differs from a dominant 7th chord in that it has a diminished 5th and an augmented 9th. The root, major 3rd, and minor \ flat 7th is the same as for the dominant 7th chord
Dominant 7th intervals: root, major 3rd, perfect 5th, minor 7th = R-M3-P5-m7 = 1-3-5-7
7♭5#9 intervals: root, major 3rd, diminished 5th, minor 7th, augmented 9th = R-M3-d5-m7-A9 = 1-3-♭5-♭7-#9
Chord equivalent: 7♭5#9 = 13♭5 on the ♭5, for example, D♭7♭5#9 = G13♭5
D♭7♭5#9 tendency: this chord resolves best to C, D, G♭, A♭ and unbelievably to G and A.
7♭5♭9/#9 intervals: root, major 3rd, diminished 5th, minor 7th, diminished 9th, augmented 9th = R-M3-d5-m7-d9-A9 = 1-3-♭5-♭7-♭9-#9
Chord equivalent: 7♭5♭9/#9 = 13#11 on the ♭5, or D♭7♭5♭9/#9 = G13#11
D♭7♭5♭9/#9 tendency: same as for the D♭7♭5#9 chord.
The 7alt chord: What is it?
The “alt” of 7alt comes from the altered scale, the 7th mode of the melodic minor scale. It is basically a dominant 7th chord that has non-diatonic chord tones.
The strictest definition is that 7alt chords have both an altered 9th and an altered 5th leaving only 4 possible chords. I like to think of them as 2 7♭5 chords and 2 7#5 chords
However, I like to add to that list, dominant seventh chords with an altered 5th OR an altered 9th, which adds the following chords to the ones above:
7♭5, 7#5, 7♭9, & 7#9.
But why stop there? You could also include dominant 7th chords with a #11 or ♭13:
7#11, 7♭13, 7♭9♭13, etc.
Check out the Wikipedia article on the Altered Chord for an inclusive and in-depth view of the subject.
In that article, it mentions the possibility of including both the ♭5 and\or #5 and ♭9 and\or #9. That is 4 altered chord tones plus the 3 tones common to all dominant chords: the root, major 3rd and flat 7.
I do have voicings for the 7♭5♭9/#9, 7#5♭9/#9 and 7♭9/#9 chords. But I never consider including both altered 5ths. Here is what you get with both 5ths and one of the altered 9ths (max for a 6-string guitar):
7alt with both ♭5 & #5 and ♭9 = 9#11 on ♭5. In D♭, I guess you would name that chord Db7#5b9#11 and it would actually equal a G9#11.
7alt with both ♭5 & #5 and #9 = 9♭13 on #5. For D♭ that would be D♭7#5#9#11 which equals an A9♭13, not a chord I’m aware of, so I guess that would be a unique chord. I’ll find some voicings for it in a later article.
Open D♭7♭5#9 and closed 7♭5#9 guitar chord shapes
Here are the chord tones for the 2 D♭ chords:
D♭7♭5#9 = D♭-F-G-B-E, where the flat 5th G is actually A♭♭ and the flat 7, is actually C♭.
D♭7♭5♭9/#9 = D♭-F-G-B-D-E and technically the ♭9 is E♭♭.
Here is a chord diagram of the symbols I use in my chord blocks:
Notes on the chord voicings:
D♭7♭5#9: For the second closed shape, I put a 5-string barre even though you only need to barre the bottom 4 strings – it’s easier to hold it that way. You could even barre all 6 if you find it hard to hold. #1 & #2 for the open chords sound identical unless you fret the optional note on the high E string of #2 which sounds super eerie. I like #’s 2 & 3. #4 sounds bad but I only have 4 chord shapes so I included it anyway.
D♭7♭5♭9/#9: #’s 1 & 2 sound the best and #4 is a little hard to hold. I fret the E at the 12th fret of the high E string for #3 because it sounds better than the open string.
How to use the 7♭5#9 and 7♭5♭9/#9 chord
Both chords have 2 tritones in them, between the M3 and ♭7 and the root and flat 5. As a result, you get the 4 strong tendencies that I mention above. So let’s look at how to use these chords using a D♭7♭5#9 chord:
1) As a leading tone chord to a D major chord
2) As a flat V of V substitution to C major. I like to call this chord substitution the ♭9 dom7 chord.
3) And finally, these two chords also resolve to the flat 5 of both C & D: G♭ and A♭.
So #’s 1 & 2 are straightforward if you ask me. But the 3rd tendency is interesting. You can make a radical key change to the tritone and do it smoothly. And of course, that could be a temporary key change where you go back to the original key with the V7 chord or another 7♭5#9 chord.
Mess around and find something you like. I also noticed, that the D♭ 7♭5#9 chord also seems to resolve to both G major and A major which is odd. Try it out for yourself and let me know if you disagree.
The tendency for both chords in roman numerals with the 7♭5#9 chord as I is to ♭II, IV, ♭V, V, #V, and VII. Hopefully, that makes sense to you.
Try out the 7♭5#9 chord if you want to add some nasty tension in your songs and give your lead guitar player some juicy notes for his riffs. Also, check out the other 2 articles I have on 7alt chords:
I hope you found some useful chord voicings and a clearer understanding of 7 alt chords. Have fun jamming, experimenting, and writing!