Why does A minor scale sound the "best" over Dm and C chord progression?

Question

I created a little loop with the following two intervals:

D A and C G

Listen here: https://tinyurl.com/ybsukagd

In looking at what scale to use to solo over that simple progression, I thought D minor scale would be the obvious choice. However, I found that the B♭ in that scale was clashing and ended up using the A natural minor scale - which to my ear, sounded "best".

I'm working on learning theory and I'm looking for the rule that tells me to solo in A minor over those two intervals (which might as well be Dm and C chords).

Any pointers much appreciated!

Answer 1

You are playing B naturals in your C chords, making them Cmaj7 chords. The Am scale contains the notes of a D minor scale but with a B natural instead of B flat. That is why it sounds better than the D minor scale.

Learn about modes. Modes are in a nutshell a way to extract 7 different scales from one by starting and ending on different notes (D to D, E to E, etc.)

In your example the A minor scale (Aeolian mode) is actually a mode built on the 6th degree of the C major scale (Ionian mode) The D Dorian mode (the scale I mentioned in the first paragraph) is built on the 2nd degree of the C Ionian scale.

So in closing the A minor scale contains the C major scale and the D minor scale with the major 6th, or B natural. That is why it works so well and is a great choice for creating melodies and improvising on that harmony.

Answer 2

There are so many options available when using that particular 'chord sequence'. You could have easily included an F♯ and it would have a different sound. Try it.

With the information you have given, there's insufficient. Saying 'the A minor scale notes' narrows things down a little - but not enough. There are three main A minor scales - natural - A B C D E F G, melodic - A B C D E F♯ G♯, and harmonic - A B C D E F G♯. All slightly different in the notes used, therefore the feel given.

Then there are a couple of minor modes _ A Dorian - A B C D E F♯ G, and A Phrygian - A B♭ C D E F G. Called minor as they possess m3 above their roots.

You could have used pretty well any of those 'scales' as your bank of notes - and each one would give a different feel. That's before we venture into D Mixolydian - which also happens to contain D A C G (your ostinato notes). D Mix. gives a major feel to it all, with a tinge of Blues. The Beatles used it in several songs.

Hopefully, given this 'explanation of a rule' you'll have more ideas that you can use. The main one always being 'if it sounds good...', but when you try out my other suggestions, you may realise there's not only one 'sounds good'.

And finally, my students are all aware that any note, at any time in any piece, in any key will fit - once they know what they're doing..! Maybe that's the 'rule'?

Answer 3

If you play Dm-C-Dm you are in D dorian and there you have the same tone resources like a minor. Of course also the D-dorian scale will fit well.

When you play with the thumb on A this is the 5th of Dm and playing all your fingers up your passage leads to E which is the 3rd of C major.

The 5th and the 3rd are the most essential intervals additional to the root of the chords Dm and C. All other non chordtones are passing tones and as you play quickly they sound fine.

But if you play any other scale or mode than Dm or Am these scales will be less congruent with DA and CG ... you probably hear D,F,A and C,E,G as you mention Dm and C major.

Edit:

I had to practice for some years all scales in all keys on the piano and on brass instruments, but just the major scale, melodic and hormonic minor scales and the triads. And today I’m getting more trouble concentrating and minding the stuff. I need to make a warming ups: transposing a piece to C major, playing the certain scale of the piece and all triads.

But there are shortcuts: You don’t need to learn all the modes. The scales are built of identical tetrachrds and If you know the scalesyou are able to play all modes like in your example: you don’t have to mind D dorian and A aeolian. This is only theory. In practice you can play in. any key and think the l.h. the chords are ii-I-ii and the r.h. plays in the same key whereby the vi degree is the root. Read here Tim’s and Michael’s answers:

How to learn the modes

Btw. John Belzaguy gives a similar explanation here.

Answer 4

I appreciate all the great responses from which I determined that learning modes is a big part of the answer to my question. Along those lines, I finally cleared up enough brainpower to take this on and realized that learning modes is not hard at all. I created this chart:

What I realized is that, if you know your major scales, it's only necessary to memorize the variations on the major scale (Ionian mode) that appear in the red box. If you practice and learn those variations in the key of C, you'll absorb them and can then practice applying them to other keys.

Intuitively, my sense is that the next step in answering my question is that by learning these modes, I will begin to "see" the chords in each mode. That will take time and is a next step from just learning the structures of the modes.