I am playing these 3 chords in the following sequence:

AM - CM - DM

What scale do they belong to?

I first thought its A Mixolydian:

// But this can't be it, because it doesn't have C#(used in A major)
Dorian      1   2   b3  4   5   6  b7 
Dorian      A   B   C   D   E   F#  G 

I tried to see if it fits Dorain:

//But this can't be it because it doesn't have C note(used in 2nd chord C major of the sequence)
Myxolydian  1   2   3   4   5   6  b7 
Myxolydian  A   B   C#  D   E   F#  G 

This seems like a usual or common sequence of chords. How can it be so complicated? Am I missing something?

  • 2
    You've found a chord sequence that isn't all contained in one scale. That's OK. Did you think it wasn't?
    – Laurence
    Commented Feb 5, 2017 at 3:54
  • Are you asking this to establish what key the piece is in, or to find a scale (set of notes) that you can use to solo over the chord changes? Doesn't A Mixolydian have F#? And A Dorian have F#?
    – Tim
    Commented Feb 5, 2017 at 10:51
  • @Tim Yes Fixed it. Well im looking for key, but my next step is to solo over it. So eventually i need both
    – user36640
    Commented Feb 5, 2017 at 13:38

4 Answers 4


The 'theory' goes as follows: it's common (and acceptable) to use chords from parallel keys. Put simply, there's always the set of 3 majors, 3 minors and a diminished that are diatonic. Let's take D as an example.

Dmaj., Em, F#m, G maj., A maj., Bm, C#o.

Now, Dm: Eo, Fmaj., Gm, Am, Bbmaj., Cmaj., Dm.

There are your 3 maj. chords!

Let's take A as an example.

Amaj., Bm, C#m, Dmaj., Emaj., F#m, G#o.

And Am: Bo, Cmaj., Dm, Em, Fmaj., Gmaj.

There are your 3 chords!

The theory, as we've said many times here (and elsewhere!) tries to explain what happens, usually in a 'human' way. It's how we are. But now that bit of 'theory' is stated, A,C and D together should make sense. It won't ever change what they sound like, though. And that is a far more important factor...

For soloing over, Am pent is a good start. It works over the Amaj, C and D with lots of complementary notes.

  • Im not sure i undeerstood But now that bit of 'theory' is stated, A,C and D together should make sense. It won't ever change what they sound like, though this well. Theory doesnt say A,C,D to be all major(there is no such scale so i assume no such theory)...Could you explain please
    – user36640
    Commented Feb 5, 2017 at 13:40
  • You appear to be somewhat entrenched in the 'if it's not part of theory it can't be allowed' school of thought. There have been several nods towards that sentiment recently. What the theory is attempting to do, quite well usually, is explain how certain things work. Sometimes it's at a bit of a loss, and that's when ears take over, because at the end of the day, any piece will survive better if it sounds good, rather than if it merely obeyed all the 'rules'.
    – Tim
    Commented Feb 5, 2017 at 14:21

The notes you have in the three chords are A C D Eb E F G.

All that proves is that "music" doesn't have to follow an arbitrary set of "rules" about "naming scales".

In the long run, learning that fact is probably going to be more beneficial than jumping through the hoop of "identifying the correct scale name".

When in doubt, throw your theory books on the fire, and just use your ears!

  • Did you miss C# which is a part of AM(the first chord)?
    – user36640
    Commented Feb 5, 2017 at 13:32

Technically, those three chords don't fit in one key so one scale (mode) won't have all of the notes exactly. I agree with the answer above that your ear is the most important thing.

An A minor scale would sound fine over this progression as would a D minor scale. A minor pent scale would work fine also.


I just googled it and found 2 unusual scales that fits in that Am Cm Dm structure.

Eight Tone Spanish Scale

A#/Bb ichikosucho Scale

So I've never heard of these scales before but they seem like fitting in that progression, I think that there is no reason to find a perfect scale that fits perfectly or finding a name for that "perfect" scale. They're all made up, just go by ear, that's the only proper way to do music. Cheers.

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