A friend is writing a song that begins with the following chord progression: Dmaj7-A-Esus4-E, and then repeats. I changed it to this (just trying things out): Dmaj7-Amaj7-A6-Esus4-E. The two A chords get half the number of beats as before to keep up with the melody. Anyway, my question is this: What the heck key is it in? At first I assumed it was D, just because that's where it starts, but now it's starting to feel like it's in E. Can anyone help?

I just wanted to thank everyone for this discussion. I'm very glad to have found this site. It looks like an invaluable resource for anyone interested in music at all.

I'm a complete newb here so I don't know what the protocol is, but I'm going to mark my question as answered (if I can figure out how to do that), even though the answer isn't definitive. This discussion will lead me in directions I've never taken, and that's more than enough to qualify as an answer for me.

Again, thanks to everyone.

6 Answers 6


This is definitely D Lydian. You can figure this out on your own if you have a keyboard to visualize everything. Your progression is Dmaj7-Amaj7-A6-Esus4-E.

Let's start with the Dmaj7. The notes are D-F#-A-C#. Now map those notes out.


Next is Amaj7.








Once we condense all these notes into one octave we see that it makes an A Major scale.

Amaj Scale

Since the progression has a focal point and tends to resolve on the IV chord (D), we know this progression is in the Lydian mode.

D Lydian

There are two types of modes. Relative and parallel modes.

The Lydian scale is the fourth mode of the major scale. This means that D Lydian is really just an A Major scale starting on D. This is an example of a relative mode because we are relating it to its "mother scale".

You can also think of a Lydian scale as a Major scale but with a sharped fourth. This is an example of a parallel mode because you are comparing two scales side by side.

It is very important that you are able to comprehend and use both ways as it will greatly benefit your improvisation, composition, or even just learning a new song.

  • 2
    Thank you for spending so much time to illustrate this. Your point about all the chords' notes forming an A Major scale was very interesting and makes me want to learn more about music theory. I am using a keyboard to develop this song, so it's very easy to visualize what you're saying. My friend (who wrote the lyrics and found this progression) is a wonderful singer and complete beginner on guitar. She sang a melody a capella to go with the progression, but it feels very pliable -- I think we could make it resolve in E, A, or D. Only a couple dozen characters left, so thanks again.
    – John B
    Jan 4, 2016 at 11:25

It depends on the context, that is, what melody you play over it. A major is one possibility. D Lydian is another one. E mixolydian is not that far fetched either. The last two are modes of A major and the ultimate answer is related to which of the three notes (a, d, or e) gives the sense of closure. It can be played in any of these three ways, and possibly others.

  • 5
    I would heavily lean towards simply calling it A-major, due to the strong dominant effect of the released E suspension (even though it's not directly resolved to A). Jan 3, 2016 at 19:10
  • 1
    Thanks, cyco130. I have no formal training, but I play a few instruments and the key for a song is usually not that hard to find. This one, especially having an unfinished and malleable melody, has been a stumper. I guess there's no real need to figure out what key it's in as long as it feels right, but it's a little annoying that I couldn't find it. A couple of good things came out of this experience, though: I found this web site and I had it driven home that my lack of formal training can be a big hindrance. Thanks again.
    – John B
    Jan 4, 2016 at 11:33

A major seems to be likely. The key signature certainly will be 3#, and it obviously isn't leaning towards F#m! Songs with A,D and E and their derivatives will generally speaking be thought of as in A. Modes of a key will contain the same notes and chords from that parent key, although the 'home' may not be that parent key. However, here, the As will tend to gravitate towards the Ds, and the Es towards the As. So, A major or E Mixolydian. Or, less likely, D Lydian.


The key is most likely D-Lydian (4th mode of A-major).

  • Wow! I didn't expect such a quick answer. I'm about to leave the house for a few hours, but I just Googled "Lydian mode" and I can see I have some studying to do. Thanks for taking time to answer.
    – John B
    Jan 3, 2016 at 16:28
  • @JohnB It has the same notes as the regular A major; it just starts on the 4th step of the scale with a D major chord and therefore sounds different (like F# minor, the 6th mode of A major, sounds different from regular A major). That is all there is to it. Jan 3, 2016 at 16:37
  • A major scale: A B C# D E F# G# A -- compare to D Lydian scale D E F# G# A B C# D
    – yo'
    Jan 3, 2016 at 16:43

I agree with the other answers, that this is definitely a mode of A major.

That's obvious from the fact that we have chords based on A major, D major and E major. The major 7th and 6th are both strongly indicative of the major triads of the same root.

(As an aside, dominant 7th is a funny chord, it has a major 3rd and a minor 7th, so it can lean towards both major and minor.)

So you will probably be doing the melody in the notes of (a mode of) A major.

Where I disagree (and this is highly subjective) is that I think it's not in D lydian, but in E mixolydian. It may start with a D, but it spends twice as long on the E. The Esus4 to E major gives a resolution to E. For me, returning to the D makes it feel less resolved, not more resolved.

The question is where to go from there. The Esus4 to E major is only a weak resolution. I tried it and found I wanted to play your progression twice, then go Dmaj7 Amaj7 E Dmaj7 (if I felt it was resolved there it would be D lydian, but it really doesn't feel resolved to me) and finally Dmaj7 Amaj7 E A. (a very strong resolution to A major.)

Bottom line: it's a mode of A major. Which one is somewhat subjective, and probably depends on how you want to finish the song.

  • I'm not near my keyboard at the moment, but this looks interesting. I'm going to play around with that, and with the melody, and see where it leads to. Thanks.
    – John B
    Jan 4, 2016 at 11:53
  • "it spends twice as long on the E" It's very common to spend more time on a chord other than the tonic. Take the "La Bamba"/"Twist and Shout" progression (I IV V7 V7), for one example. Jan 5, 2016 at 15:16

I like it! For what it's worth, it sounds to me like a close relative to the progressions of Tracy Chapman's "Fast Car" or Tom Petty's "Learning to Fly". (I think those have a minor vi in place of the Vsus4 (so, F#m instead of Esus4), but that chord has a similar function.)

There'd be no doubt about the key center if it weren't for that initial D; if there was an A in place of the D, it'd be roughly: A, A, Esus4, E. Which gives a clear Esus4, E, A cadence, an extremely common cadence in A, which resolves to the A at the start of the next phrase. But instead of the expected resolution we get Esus4, E, D. To me it feels like that's just delaying the resolution one bar, but it does give the progression that restless unstoppable feeling, since it's missing the obvious stopping point (or since the obvious harmonic stopping point is out of sync with the phrasing).

Anyway I'd still call it "A major", if only to keep things simple.

But that's all a bit academic. In practice, if you're trying to figure out how to play it, trust your ear. And if you're writing it down, you just need a key signature, and for that everyone agrees there's an obvious choice: F#, C#, G#.

  • Oh, also the Foo Fighters, "Wheels". Once that chord progression's in my head, it keeps turning up more. Jan 4, 2016 at 15:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.