What key could the progression Cm - G - Dm - Am be in?

Question

I'm working on a song (my first ever actually) and I love the chord sequence:

Cm - G - Dm - Am

I started off working in C-Major, but borrowed Cm from the parallel minor key C-Minor. But really, in my mind, it's in A-Minor not C-Major... however is taking a chord from the parallel minor of the associated major key even "a thing"? Cm is the only "weird" chord I want to use (I probably will use F and Em elsewhere) and while I know you can put any chord in any key if it sounds right, how would more knowledgeable theorists analyse this, and is my understanding of why Cm 'fits' in the key of A-minor reasonable?

Update: I recorded a guitar part and looped it as the "verse" to my song:

I actually played it a tone up (Dm - A - Em - Bm) as it's more natural (I'm playing Dm, Em and Bm using the Bm barre shape but with an open top E) but you can transpose your answers however you wish as long as it's clear!

Answer 1

I'll tell you what my ears tell me. I'm referring to the progression that you actually played:

Dm A Em Bm

I hear this progression not in one key but I hear two tonal centers. The first is A major: iv I. The second is B minor: iv i

There are several reasons why this works and why it keeps circling seemingly without end. In both tonal centers it is a subdominant-tonic progression (no strong dominant, hence the ambiguity). Furthermore, both tonal centers are closely related (3 sharps vs 2 sharps). Also, the final chord Bm is very much related to a D major chord (relative keys), so when the progression moves back to Dm, it sounds like going from (D) major to minor, which is yet another connection of the two parts of the progression. Last, and maybe most importantly, there is a strong underlying chromatic guide tone line through this progression: F-E-G-F#(-F-etc.). This creates this endless circle effect.

Answer 2

Whilst on a major scale ,borrowing chords from the minor scale with the same name is common (and vice versa). Really common to be honest. Some of the most common borrowed chords are the V (dominant), IVm and bVI.

Now for your progression. Since you said you were on C major, we have:

• Cm (borrowed)
• G (V)
• Dm (II)
• Am (VI)

Or if we are on A natural minor, we have:

• Cm (borrowed)
• G (VII)
• Dm (IV)
• Am (I)

In the most common progressions, after the V or VII you would find I or VI. Not that what you have is wrong, but it is unexpected. (I personally like these).

I think that if you were on C major, it would be the most fitting to change the first chord from major to minor. C to Cm. This usually happens after a dominant chord.

So, if you had a progression like C-G-Cm, it would sound really good. It is a common progression.

So, your progression could make sense in the C major.

As far as A minor gores, substituting the III with the IIIm is something I haven't really seen (or don't remember). But, like you said, if you like it, keep it.

Answer 3

I mostly agree with Shevliaskovic on his approach where A minor and C major are the two most likely, however I want to point out a few other possibilities.

If you look at the notes you use in your progression, the only note outside of the key of A minor and C major is Eb, but E is also used in your piece in the Am chord. So if you put all the notes together you would get the C Major/A Minor blues scale. It's not really a key, but there's nothing stopping you from using this scale to create chords and it will also give you a better way to improvise over your progression nothing is really borrowed.

Another way to look at it is calling it C minor, but deriving all the chords from the melodic minor ascending scale and just borrowing the E in the Am from the parallel major. This is slightly clunker then calling it just C major or A minor with a borrowed chord, but it makes slightly easier to think about in terms of soloing and melodies and in my opion explains the progression a little better then just thinking C major or A minor.

Answer 4

There are two ways to determine what key something is in. The first is to look at the set of notes (the scale) that you're using, and find a key signature that matches. The second is to find which note chord is being "tonicized." This is done by using a rising-fourth chord progression, which acts as a V-I (dominant-tonic) relationship. Both of these methods can be circumvented or subverted: the first by using chromatic notes outside of the scale, and the second by using secondary dominants. It is worth noting that, since the major and (natural) minor scales share the same key signature, the second method (tonicization) is the best way to distinguish between them.

In your case, neither method works completely:

• There is no rising fourth progression at all. In fact, every progression is a falling fourth (also known as a plagal cadence), except for the rising third at the end that takes us from Am back to Cm. As a result, there is no chord that is tonicized. This means that even if we could pick a scale, there's no reliable way to distinguish which mode of the scale (such as major or minor) we are using.

• There is no single scale that contains all the notes that you use. Specifically, as Dom notes, you use both an E and an E♭.

So there is no correct answer to the question of what key this progression is in. There's simply not enough information in the progression to establish a key. That's not to say that it is atonal -- there are several keys that it could belong to, but there's not enough information to say which one it definitely is. This is called being tonally ambiguous.

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As exotic as it might sound, tonally ambiguous chord progressions really aren't all that uncommon. This type of music is also often called modal, not because it is necessarily in a specific mode (e.g. Mixolydian, or Phrygian, etc...) but because it avoids (or uses sparely) the conventions of tonal music. Some common features of modal style music include: a preference for plagal progressions (falling-fourths) over dominant-tonic progressions (rising-fourths), a frequent use of borrowed chords (♭III, ♭VI, ♭VII), a disreagard for the expected chord quality (using majors instead of minors, or vice-cersa), and using the ♭seven of the key to avoid a strong dominant sound. This style is especially common in modal folk music, or blues-inspired music. It could probably be debated whether it arose by intention, or by accident due to the convenience of certain chord shapes on the guitar.

At any rate, one way that this technique can be used is to weaken the tonic during a verse, so that when a dominant-tonic progression is finally heard in the chorus it will be much more striking. Once you're ready to define the key that you're really in, you need only pick a dominant chord, and following it with a tonic.

Another way that tonally ambiguous progressions can be used is to change between two different keys. In fact, this is an excellent way to modulate gracefully without being noticed.

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So which keys could this progression be used in? Many of the existing answers have already given good options for this.

If you go back to looking at the scale, you'll notice that any scale with an E♭ also has a B♭ in it. Since your progression contains a G chord (which has a B natural in) the simplest assumption is that the E♭ is the chromatic note (and thus the C minor is the borrowed chord). This would place the piece in C major/A minor (again, there's not enough information to say which).

On the other hand, you might consider that E♭ and B♭ are part of the scale, in which case the G major chord would have to be borrowed (which suggests C minor, with G being its dominant). However, this would also require the A minor being borrowed (vi instead of the usual ♭VI), which I don't think is a common borrowing.

In fact, if you restrict yourself to keys that only need to contain the roots of all four of your chords (instead of all the notes in the chord), then you could use any key which contains the notes C, D, G, and A:

By my count, these are:

• B♭/Gm
• C/Am
• F/Dm
• G/Em

As I mentioned earlier, you can make any one of these keys sound like the home key by simply playing a dominant-tonic progression in that key. As an example: if you wanted to go to Dm, simply replace the A minor chord with an A major (or better: an A7) then follow up with a D minor and you're there. You could even go to D major this way, if you wanted to.

Answer 5

EDIT: Clarified that the logic outlined herein is best explained as parallel modulation between the MELODIC minor (not natural minor) and major key (see explanation below).

Well there does not seem to be much agreement on what key the song is in and I have seen no completely convincing arguments that put this progression solidly in any one particular key.

I have listened to the sound file and played it myself using the Cm - Am progression and the one played in the recording (Dm - Bm).

What I can say is that is a very effective piece of song composition and succeeds beautifully at conveying a very unique and distinct feeling. To me it defiantly feels more minor than major and seems to create an ambivalent feeling of uncertainty. Or a feeling like the waves coming to shore and then rolling back to sea. Very melancholy as well.

I am going to say that (aside from the simple fact that the Cm chord is not often used in the key of Cmaj) since it really feels/sounds very minor, it's difficult to reconcile it being only in C major (or any major key given 75% minor chords). So I would say that it is an arrangement that to a very good effect uses a subtle but constant back and forth parallel modulation between C melodic minor and C major.

C melodic minor contains the Cm the Gmaj and the Dm but would use an A half diminished chord (A C Eb) instead of an A minor. If we used A half diminished instead of Amin in the progression - it would fit squarely in the key of "C melodic minor" (not C natural minor or C harmonic minor).

And since the G major chord is in both the melodic minor and major parallel keys, it's difficult to tell exactly where the modulation takes place and that to me is part of what makes this progression so powerful. It's like watching waves come to shore and back - you can't really tell exactly when the wave stops coming in and starts to go back out (what point they actually reverse direction).

The ongoing back and forth parallel modulation creates a yin - yang, ebb and flow effect. Perhaps unconventional, but again very effective at conveying a certain swaying movement to the music and certain emotional feeling.

So rather than try to put it in a box and say it's definitely in this key or that, I think we should just agree that it can be described as a very effective use of parallel modulation between the melodic minor and major key of whatever tonic chord we open the song with.

I see this as a great example of a composer willing to be inventive and think outside the box. Sometimes this type of unconventional device is beyond classification. Other than to just say it's brilliant!

Answer 6

If your sample is anything to go on, your progression isn't really Cm-G-Dm-Am (or its transposition up a tone), it's (Cm x 3)-G | Dm-Am-Cm-G | (repeat last phrase ad lib.). Each phrase is ending on the major chord, so what you really have is, tentatively, i-i-i-V | (v of V)-(v of ii)-i-V | etc.

I say "tentatively" advisedly, as Laurence is quite right that the passage is tonally ambiguous (which is not the same thing as atonal).

What tends to make C major or minor somewhat ambiguous is that C is nowhere asserted as tonic; rather, it is implied by repetition in the first phrase and the i-V half-cadences at the end of each phrase. Also, of course, either Dm and Am are substitutions (for D° and A♭ respectively) in C minor, or Cm itself is a modal substitution in C major.

No doubt other interpretations are possible, which reinforces what I say about tonal ambiguity.

The start of your second phrase gets its justification through the continuation of the cycle of fifths from the preceding phrase end. Within the phrase, you have a pattern of root motion of down a fourth, up a minor third, down a fourth, so the phrase itself divides into a short harmonic sequence. In effect what the Dm and Am are doing is creating a kind of dominant prolongation on G, as they continue the root motion outwards from G while remaining diatonic in C major. (It is incorrect to call it two keys - there hasn't been enough done to establish a modulation.)

However, I think that, if you were to play a C chord (major or minor - it doesn't matter) immediately after the G chord, you'd very rapidly disambiguate the phrase. In fact, you may find that a bridge of some sort starting on C minor, falling in the flat direction by fifths and rising back to G or G7 works well for this. (That's assuming you want to disambiguate it. It's not always necessary.)

But... the beginning of understanding what you're doing with this passage is to understand how you've phrased it, and that is not with Cm-G at the beginning, but at the end of each phrase.

Answer 7

Some observations:

1) It's interesting that base of the chords moves by fifths, I mean:

• C +5 --> G
• G +5 --> D
• D +5 --> A

Is this a thing? I don't know...

2) Having plain chords Cm - G - Dm - Am (having no seventh, sus e.t.c) that contain both Eb, E and F as notes, makes it imposible to be just one minor or major key.

3) Transposing it by a tone (just like the OP suggested and played) gives Dm - A - Em - Bm and it's almost in natural A key. So the progression would be totally "make sense" if

Dm (IV) - Am (I) - Em (V) - Bdim (II), "only" two notes change (quite different sound, I know).

Answer 8

I'm going with assuming these are the chords from a C Dorian mode, meaning you are really in the key of B flat.

The two accidentals now are changing your G minor to a major and raising the fifth of your A chord to make it a regular minor. Otherwise everything adds up.

Your F chord will also fit right in. Your proposed Em will be interesting to deal with as it is not a shoe in.

Answer 9

Taking a chord from the parallel minor of the associated major key is a thing!

Let's break your song down to simple notes:

• Cm chord - C, Eb, G
• G chord - G, B, D
• Dm chord - D, F, A
• Am chord - A, C, E

The only accidental here is Eb, but we also have B and E, so it's safe to say we're not exactly in Bb major/G minor. Notes C, D, G and A appear in more than just one chord, and they are mostly minor chords so the A minor sound is surely present here.

The Cm chord itself has C and G, so the only anomaly is that Eb. This note can be considered a tension, because the dissonance it creates contributes to it's purpose inside the song. You need that Eb. It's also a nice melody movement from the E in the Am chord.