It seems like common practice to treat #9 chords as altered chords and, being guitarist, the most common voicing of them I'm familiar with is the Hendrix chord:


For those of you not familiar with tablature, that's E, G♯, D, and F♯♯. There's no fifth there, but the chord name doesn't specify that the fifth is altered. Yet, I can't help but feel that it wouldn't sound right with a perfect fifth. If you're using the altered scale over this chord, that makes sense as well. It only has the ♭5 and ♯5. I know that it's music, so I can do whatever I want and I should play whatever sounds good, but I'm looking for evidence, preferably from some notable jazzers, as to how the fifth of this chord acts.


It's important to realize that there are two basic flavors of that chord: the first being the "Hendrix chord", which acts as a I chord, i.e. you use an E7/#9 in a song that is in E (like Purple Haze). Here, you can't use an altered 5th, because this would take away the stability necessary for the I chord. You could use a perfect fifth though (but I've never heard Hendrix do it). This chord basically comes from playing the blues scale over a dominant seventh chord. (Note that the b5 in the blues scale is a passing tone, so you wouldn't want to add it as a chord tone here).

The other, very different use of this chord is as an altered dominant chord functioning as a V chord. I.e. an E7/#9 would now be used in a song in A or A minor. Here the perfect fifth would be relatively unusual. There are basically three common options: b5, #5 (b13), or the (natural) 13th replacing the fifth (I've heard John Scofield use that chord: E13/#9(no 5) ). The corresponding chord scales would be altered (b5/#5) or half-whole octatonic (if you want the natural 13).

  • Ah, this distinction is very helpful. I really only know the voicing for the Hendrix chord, but I was thinking of it functionally as a dominant chord, so that probably accounts for any confusion on my part. Thank you. – Dan D Mar 19 '15 at 21:06

You have to remember the full chord is an E7#9 meaning that the chord is a E7 with an added #9. The notes of the E7 are standard unless otherwise stated. It is an altered chord because we're adding a #9 which is considered altered tone because we are taking the natural 9 and raising it or altering it to get the sound we want. However just because the 9th is altered does not mean the other notes like the 5th are altered. There is an E7#9b5 and an E7#9#5 that do have altered 5ths, but this is not the same chord as an E7#9 you need to notate what notes are altered they are not implied.

In general you can omit perfect 5th from almost any chord and have it be the same chord because of how the harmonic series strongly implies it. Like stated above the same does not go for b5 and #5.

  • I understand the theory behind building the chord. I guess my point is that it seems like if the fifth is not omitted, it ought to be altered. Otherwise, it almost becomes to stable to my ears. It seems like a lot of jazz interpretations include altered extensions that are not otherwise stated on a basic lead sheet, so I was wondering if this particular chord has any sort of precedent with non-explicit altered fifths. – Dan D Mar 19 '15 at 19:49
  • You've covered it well. #9 stays #9, and the other usual alternatives are b5 and #5, although the E7#9 is altered enough for a lot of circumstances, with or without a P5. – Tim Mar 19 '15 at 19:53
  • @DanDavis my point is that if it was intended to be a b5 or a #5, it would be noted. Just because you think one chord sounds better than another does not mean that chord should be played. E7#9 implies a perfect 5th whether it's there or not. – Dom Mar 19 '15 at 20:32
  • True. That makes sense. I see where the question doesn't really make a lot of sense now. – Dan D Mar 19 '15 at 20:37
  • Whether you alter a specific tone depends on context - it depends on the tonality, which is established by the surrounding chords. So it's a bit pointless to talk about a single chord as if it stands on its own. – Michael Martinez Mar 19 '15 at 21:26

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