I was looking at the sheet music for purple haze by Jimi Hendrix and I was pretty confused.

The first two bars, and all over the song, has a LOT of accidentals. Then the root of the first chord was also an accidental. I just couldn't figure out why the song was determined to be in the key that the sheet music states it is.

How is it determined that the tonal center is derived/fits from this key?

  • Purple Haze begins with a few tritones, which are weird and live in a key known only to Jimi :) But more seriously, I don't have the music but the key is probably based on the harmonies that exist once the verse itself starts. – Andy Jul 13 '16 at 16:13
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    Whilst Jimi played it in E - a sort of amalgam of major and minor, by using his signature chord, E7#9, he often played on a guitar that was not at concert pitch. No digital tuners then. So possibly the recording transcribed came out in Eb, and the writer wanted to 'get it right'. Show us the dots, please! – Tim Jul 13 '16 at 16:46
  • The soloing and riffing are mostly E pentatonic minor, so I would have transcribed it in E minor myself, and used accidentals for any chords "borrowed" from E major. It's definitely in E of some flavor. – Todd Wilcox Jul 13 '16 at 16:56
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    @JohnandLynHenry - I'm no lawyer, but I believe a snippet is ok. I've done that, properly credited, and no one yelled at me :) – Mike Hildner Jul 14 '16 at 16:04

Basically, it's a shortcoming of traditional notation to be able to write down blues chords and such. I assume the notation is E major (4 sharps?)

Watching the video, a couple things are fairly clear.

  1. In the introduction, Jimi's exploiting the tritone, based on E, the tritone interval for which is B-flat. So there's one accidental for ya ... the bass would be playing Bb against his E.

  2. There are basically only 3 chords in the song, an E-type chord, a G-type chord, and an A-type chord. So the songs not so much in E major, but a minor-ish modal variation of E.

Since the G-Major chord doesn't technically "exist" in the key of E-Major ... you'll have accidentals every time it appears.

Keep in mind also that blues scales generally depart from both major and minor paradigms ... another opportunity for accidentals.

Finally, the E chord Jimi uses most of the time is the "Hendrix Chord", typically notated as E7#9. Wikipedia has some of that info in the entry for the song.

Hope this helps.


When the composer of a given piece of music is not the one to write up the sheet music, the key/time signature/etc. are up to the discretion of the transcriber. In some cases, they do a terrible job, leaving anyone looking at it confused or annoyed trying to read it as they chose to transcribe it. I suspect that some companies that publish this material use computer algorithms to analyze and transcribe but I don't have any evidence for that claim. When something is labeled "official", as you mentioned in a comment, you would really need to determine in what regard it is official. Jimi likely didn't sign off on it... It may just be indicating that it is released with the proper licensing.

From what I recall of this song, it wouldn't exactly be in a single key, ie, not all of the chords can be derived from a single tonal center/key. In particular, the E7 chord contains a #9, which cannot be derived from any naturally occurring any key.

  • We call it a 7#9, but it could be (and sometimes is) called dominant 7th with a minor 3 added. Thus it has been borrowed from the parallel minor key. – Tim Jul 15 '16 at 6:45
  • @Tim - I can understand how and why it would be referred to that way, especially for those that don't understand the theory of extensions and alterations. I'm not so sure what you mean about borrowing from the parallel minor key, though. Do you mean that just the minor 3rd is borrowed? That's not how I typically see borrowing referred to, ie, not a single note added to a chord that is not borrowed. – Basstickler Jul 15 '16 at 17:51
  • Borrowed is generally from the parallel key. As in E major, any chords/notes from E minor are also fair game. Not a theory rule, but seems to happen a lot – Tim Jul 15 '16 at 19:53
  • @Tim - I won't say that it's wrong, just not how I've seen the term used. Ultimately, regardless of what the established theory says, if it makes sense and conveys the intended meaning to the player, I think of it as correct. Unless of course it is for a theory exam, then you're kind of stuck calling things based on the established theory. – Basstickler Jul 15 '16 at 20:27

the key is in technically Bbmin because he tunes his guitar down a halfstep but it seems most people keep it in standard so for the sake of argument lets call it Bm. in the key of Bm, E technically would be a minor chord but he plays an E7, this works because he adds the #9 on top (which is just a minor 3rd up an octave) and does not play the 5 allowing it to act in the role of an Em7 which would typically have a minor 3rd (in this case a #9) and a minor 5th (which isnt used). and the rest of the chords fall in the key of Bm/Dmaj. the G is the 4th, A is the 5th, Bm is the 6th and D is the root. You can make the argument you can improvise in the key of E when the E7#9 is playing but tbh I would advise something more like the E blues scale because of the minor 3rd and you would be able to play the minor 5th without consequence but in E Ionian, accidentally playing Gb and A would mess you up.

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