3

enter image description here

Above is actually a thread from reddit, OP asks what Am7b5 is doing in the piece. (I am actually not sure posting it here is OK in the first place)

https://www.reddit.com/r/musictheory/comments/1boqdi1/whats_the_function_of_a7b5_in_c_minor/

here is the thread URL.

My question is, there are comments saying that Am7b5 is a borrowed chord from Dorian, when some other comments argue that Am7b5 can be explained by melodic minor scale(to which I also agree).

But again someone else says in jazzy 1 6 2 5, Am7b5 is actually Dorian.

Can someone explain why Dorian is brought up for Am7b5's role when melodic minor alone can explain it?

4 Answers 4

2

They're talking about dorian, because the "true" VI chord in C minor would be AbMaj7. One could consider that the A natural comes from melodic minor, but then there's the matter of the previous chord, C-7, which contains a Bb. "True" melodic minor would have a B natural. So, given the presence in the measure (in the harmony, that is) of both A natural and Bb, there is the suggestion of dorian (C-D-Eb-F-G-A-Bb-C). In the chord-scale approach to jazz improvisation, it would make sense to play the C dorian scale over the measure, because the switch to melodic minor (i.e., play B natural) risks an awkward sound — Bb against one chord but B natural against the other.

However, this is a perfectly ordinary variation of i-vi-ii-V that occurs in jazz frequently. Jazz harmony doesn't attempt to adhere strictly to the same conventions as does classical music. Whether the chord is considered to come from dorian or melodic minor really has no bearing except as a purely academic question. Jazz is comfortable interchanging the various minor scales plus dorian and just calling the whole thing "minor".

1
  • 1
    Jazz is comfortable interchanging the various minor scales plus dorian and just calling the whole thing "minor". -- so is classical. Even more so, in fact.
    – phoog
    Mar 31 at 5:05
1

Am7♭5 contains the same set of notes as F9 (minus root). So playing an F9 chord would work just as well, with the possibility of it having an A as the lowest note - not clear from a lead sheet, unless 'F9/A' was written. Although Cm6 would be an even better exact substitute, in an inversion.

Considering F9, that would then put the chord in question as 'borrowed' from the parallel key, C major. Considering Cm6/A, it stays in minor. And then follows the familiar 2-5-1 change as found in so many jazz arrangements, the Dm7♭5 reverting the key back to Cm.

1
  • 1
    How is F9 from C major? FMaj9, yes, but F9?
    – Aaron
    Mar 30 at 10:11
0

As @Aaron pointed out in his answer this chord can be interpreted in all of the ways you mentioned but it is best thought of as a minor version of a 1-6-2-5, which is very often used in jazz. It is also not usually a part of the original harmony but added as a reharmonizarion of standard tunes like this one. In C minor it creates a nice voice leading of Bb-A-Ab-G in the chord progression. It is used by some in other songs like “How Deep is the Ocean”, “Yesterdays” and “Summertime” but like I said, it is rarely part of the original harmony of these songs. It is the same harmonically as going from a Im (or Im7) to a Im6 but adds the bass motion to the 6th of the Im6 chord, thus giving you a VIm7b5.

Confirming my point about this usually being a reharmonization, in the recording of “Angel Eyes” by the composer Matt Dennis, he does not use this chord in either bar 3 or bar 6. In bar 3 he plays a full bar of Cm and in bar 6 he plays an Ab7 in place of the Am7b5. He also plays the song in another key, Eb minor but I have transposed the chords to their C minor equivalents.

0

There are many questions and other things to address here.

"In C minor, is Am7b5 a borrowed chord from Dorian?"

I can't see any benefit in thinking about borrowing from Dorian, definitely in a tune like this. Who borrows from a mode anyway? Is that even a thing?

"OP asks what Am7b5 is doing in the piece"

What the Am7b5 chord is doing: it's a middle-point between Cm and Ab that provides a "something changed" feeling without actually doing much. Whoever wrote the chords wanted to have a change halfway through the bar, and they could have used, say an F9 chord as well. The Am7-5, which can be written as Cm6/A, gives a clear one-step bass movement to the target Ab.

there are comments saying that Am7b5 is a borrowed chord from Dorian, when some other comments argue that Am7b5 can be explained by melodic minor scale(to which I also agree).

What is this "explaining"? How does a scale "explain" a chord? I don't understand this thinking. Do you mean that the whoever wrote the Am7b5 chord must have been thinking about a certain scale, in order to come up with Am7b5? No other chain of events is possible?

Can someone explain why Dorian is brought up for Am7b5's role when melodic minor alone can explain it?

I haven't and won't read the Reddit thread, but a C Dorian scale is one possible scale to overlay on top of an Am7b5 chord. C melodic minor is another.

The general idea I feel is mistaken here is that every chord "comes" from exactly one scale. It's weird that perfectly sane, logically thinking people can think so. What actually happens is more like the other way around. A musician sees a chord symbol and thinks: what scales or 7-note chords can I fit over this chord. A common method used by jazz musicians is extending a chord to a full "13th" or 7-note chord, or even an 8-note chord, which they equate to a scale. Diminished scales have 8 notes per octave. And of course you can play a chord with all 12 chromatic notes appearing somewhere.

A chord comes from a scale, if that scale is what the person was thinking about who decided on that chord. But you cannot know what they were thinking.

One important mechanism to see is chromatic alterations. There is no scale which dictates what you may or may not do, it's the other way around. "The scale" or harmonic context, is at your mercy. Whatever chords you play, scales are your humble servants and they adjust according to the chords. If you start in Cm, but then you play an F major chord, the A scale slot is violently forced to move to natural position. Maybe it used to be an A flat, but you played an F major - now your A is natural, no questions asked. The scale came from the chord. Not the other way around.

However, if you want to play modally - and the tune in question is totally and absolutely and completely not modal - then your tonic and the set of notes around it are restricted. You cannot play notes outside the mode, because if you do, the modal feeling is destroyed. If you're supposed to create a C Dorian feeling, and if you play a chord with an Ab note, the mode breaks down and is no more. You ruined the mode. The modal feeling died and it was your fault, you killed it.

But this tune is not modal.

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.