Find out scale from these 3 chords

Question

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?

Answer 1

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.

Answer 2

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!

Answer 3

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.

Answer 4

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.