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I know there are certain types of chords which are the Minor 7th, Major 6th, Minor 7th Flat 5 AKA Half Diminished 7th and Minor 6th chords. The Major 6th chord contains the exact same notes as the Minor 7th chord but have different root notes. The same is with the Minor 6th chord containing the exact same notes as the Minor 7th Flat 5 AKA Half Diminished 7th chord but have different root notes. There is even a Major 6th Flat 5 chord that has the same notes as the Minor 7th Flat 5 AKA Half Diminished 7th and Minor 6th chord but it has a different root note and the 5th note has a different name (example: in the E flat Major 6th Flat 5 chord, the 5th note is referred to as B double flat instead of A natural). So, I'm curious to know what it is called when the chords contain exactly the same notes but have different root notes of a chord.

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  • Sorry, I'm having trouble understanding the premise. Not counting enharmonic equivalency —that is, as long as we don't say that a chord with an F# is "the same" as a chord with a Gb—do any two chords really have the same pitches? Aren't you just describing inversion? And maybe this is my ignorance, but what is a "Major 6th" or "Minor 6th" chord? Jan 6 at 18:58
  • Oh I see, "sixth chords" are for a jazz or pop context, in which what looks like, say, a C minor 7th chord in first inversion, is understood as an Eb major chord with added C. I'd say you don't have to worry from an analytical perspective because "added tones" don't affect the name; one is a type of C chord (inverted) and the other is a type of Eb chord. Jan 6 at 19:02
  • Could you clarify why "inversion" is not an answer to your question? Please rewrite your question so that it uses short and clear sentences, it's hard to understand as it is. Also, what exactly do you mean by root "position"? Word "position" is sometimes used to point the highest note of the chord. Is that the meaning you have in mind? Jan 7 at 0:50
  • But the answer remains the same, theres no real accepted general name for this. You just need to know that when you invert some chords they end up looking like another familiar chord. You can name an inversion of any chord as if the root note had moved to the inversions bass note as the chord was inverted in a new way in every case, though some of these new names would be pretty odd and not that useful. Most chords, when inverted in one way or another, end up looking like another familiar chord at some point, and just noting this for potential use in your playing is all you need to do, really.
    – OwenM
    Jan 7 at 1:14
  • It has a practical use, though, if you are jamming on a Cm6 chord for 16 bars, and you want to do something to vary your playing you can remember that Am7b5 fits those notes too, so you could switch to that for a bit to add variation. Long term it's probably better just to learn all your inversions but all of our playing is made up of little familiar bits that we have remembered from practice and come to mind quickly on stage, and if these particularly similar chords help that it can be a 'way in' to creating more interesting music when improvising.
    – OwenM
    Jan 7 at 1:23

7 Answers 7

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...Minor 6th chord containing the exact same notes as the Minor 7th Flat 5 AKA Half Diminished 7th chord but are in different root positions...

Not different "root positions" I think you're looking for the terms "inversion."

A min6 chord and min7b5 chord can be inversions of each other.

It's funny you brought up the word "root" because the root of a chord never changes regardless of inversion or voicing. If we put actual roots to those chord symbols - Cmin6 and Amin7b5 - then technically those chords are not inversions of each other. They are two different chords, two different roots. It's tedious, but Cmin6 and Cmin6/A are inversions of each other, and Amin7b5 and Amin7b5/C are inversions of each other.

Most people seem to say "six of one, half dozen of the other", but in pop and jazz when these chords are usually in root position, it's worth recognizing that the min7b5 is usually a ii chord in minor, and min6 is often the minor tonic i. Function-wise, those aren't interchangeable.


...I'm curious to know what it is called when the chords contain exactly the same notes but have different root positions.

I think understand your question now. In the case, for example, of Cmin6 and Amin7b5, the tones are all A C Eb G, but the "position" of the root in that set of tones changes from C to A.

There isn't a name for that, but it brings up some points:

  • It asserts the idea of a added sixth chord. That goes way back to Rameau's harmony theory. Strictly speaking, this idea is at odds with the notion of tertian harmony and chords built of stacked thirds.
  • Strictly speaking, it means you should not consider Cmin6 and Amin7b5 as inversions of each other, if you give different roots, then you're really saying they are different chords, this is basic view of jazz/pop harmony, they are different chords
  • Typical Roman numeral analysis doesn't allow for an added sixth chord. You would not analyze, for example, C: IVadd6, it would instead be C: ii6/5, the tones involved being F A C D, so D F A C and F A C D in RNA are viewed as the same chord, but in different inversions
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  • Not just chord inversion. Jan 6 at 20:05
  • @MatthewtheMusicFan2022, I don't understand your comment. What other kind of inversion do you mean? There are other inversion functions, like inverting a melody, but that's a different context. Jan 6 at 20:09
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There is no special name. They're not even inversions - unless you want to call root C6 as an inversion of Am7 1st inversion - which it obviously isn't - it's the same chord with the same voicing.

The names may well show what particular function one or the other has, as far as analysis is concerned, but in a piece of musc, particularly pop, there's no compunction to play root version of any chord, so C6 and Am7 could be the same.

Consider also the augmenteds and diminisheds we use. Co is the same as D♯o is the same as E♭o is the same sa Ao, etc., etc. Inversions is as close as it gets, except it's not an apposite word to use.

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There's two pairs of chords you're likely to come across doing this, exemplified by C6 / Am7 and Em7♭5 / Bbm6.

There's no real confusion between the first two. They do different things - C6 is a tonic with a purely decorative added note, Am7 is likely to be part of a 'cycle of 5ths' sequence like Am7 - Dm7 - G7 - C. You will occasionally see a tonic C6 labelled Am7, but it's likely to be in sheet music from the 1930s and is less a harmonic description than an instruction to a ukulele player where to put his fingers.

The second pair are a bit more interesting. Even when Em7♭5 precedes Am7 - Dm7 - G7 - C in an even more extended 'cycle of 5ths' string - and even when it's rooted with E - it often gets labelled 'Bbm6'. This might be because publishers consider a m6 chord 'easier' than a m7♭5. Or it may be because it's a 'jazz' chord that also has a 'classical' label - the Victorian theorists would have called it an Augmented 6th chord.

We could also discuss whether C♯ - E - G - B♭ is a Diminished 7th or a rootless A7(♭9) - which is very likely what it functions as.

But, to answer your actual question, no there's no particular musical term for this sort of thing. I suppose we could speak of a set of notes being ambiguous.

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Yes there is indeed a term for this. This is a very interesting phenomenon of harmony. You have described it well, the same grouping of tones can be interpreted as two different chords depending on how we organize the tones in our mind.

Just to make sure we are on the same page. An example could be the following two chords:

  1. F-A-C-D
  2. D-F-A-C

The first chord could be understood as F major with added sixth. The second chord could be a D minor seven (or F major with added under D which connects to what follows below)

Jean-Philippe Rameau is famous for working on this phenomenon. He referred to it as the Double Emploi. This allowed Rameau to conceive of the same group of tones in two totally different ways.

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  • Great answer, but needs some refinement: 1) Rameau's double emploi was specific to the subdominant chord: IV with an added sixth = ii[6-5]; 2) "...in two totally different ways" is an overstatement. Double emploi just meant that the added sixth/minor seventh chord could be interpreted according to context.
    – Aaron
    Jan 10 at 5:33
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Like Aaron said, there is no specific name for these similar chords, they are simply inversions of each other, or chords with different bass notes. For clarification, C6 and Am7 have different roots. C6 and C6/A have the same root but different bass notes. Here are some examples:

C6 = Am7/C or Am7 in 1st inversion (3rd in the bass)

Am7 = C6/A or C6 in 3rd inversion (6th in the bass)

Cm6 = Am7b5/C or Am7b5 in 1st inversion (3rd in the bass)

Am7b5 = Cm6/A or Cm6 in 3rd inversion (6th in the bass)

Another point, your statement “The Major 6th chord contains the exact same notes as the Minor 7th chord but are in different root positions…” is not accurate. It is very specific chords that share the same notes, not just any major 6th or minor 7th chord. The root of the 6 chord has to be exactly a minor 3rd above the root of the m7 chord to contain exactly the same notes and vice versa.

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I don't think there is a given name for what you describe, and I do think we could use one.

Ootagu's answer seems to be on the right track. (If Aaron's comment is correct, Rameau's double-emploi is at least a subset of the phenomenon you describe.)

If I were to coin a term for it, I might just borrow one and use "double entendre". I think pun is more commonly used with respect to tuning and intonation (e.g. when a single equal-tempered pitch takes the role of two different just-tuned pitches within a passage.)

I found it to be an important tool when playing bass guitar (or low synth) in bands where I composed my own parts based just on hearing the guitarist(s) play. E.g. when the guitar played D-G-B-E, I had the power to choose the root and I make everyone hear it as a G6 by playing a G or an Em7 by playing an E.

Sometimes I intentionally chose one I knew the guitarist did not mean. I don't think there's a term for that either, but I'll call it a Bass Mondegreen.

I will also like to add that the other tetrad you mention (m6/m7♭5/M6♭5) has another pair of related magical properties: It's a 9th chord missing it's root. Example: Am6/F♯m7♭5/C6♭5 contains F♯, A, C, E. Add D below it and it's a D9. Even without its root, these tones suggest the D should be there because of the harmonic series. They approximate the 5th, 6th, 7th, and 9th harmonics of that missing root.

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It's called chord inversion.

https://en.wikipedia.org/wiki/Inversion_(music)

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  • Your answer got 2 downvotes just because you said it’s called chord inversion but it was before I edited my question title just for clarification. Mar 5 at 16:51

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