Im6, why?

[alez]

All,

As far as I can see, from a theory perspective and also from Jazz Oud's ideas on chord tension vs key tension, that major 6th has all the wrong ingredients: it's a tritone away from the third of the chord and it's not even diatonic to the key. Yet there it is, present on a very significant % of classic jazz standards in minor keys, and it even has a tonic function! And then IV in minor rarely comes as m6, despite the fact that it's subdominant function and its major 6th is diatonic to the key.

I think it's all pretty weird.

[alez]

I thought the major 6th had purely melodic purposes in minor, related to the notion that the melodic minor scale was kind of invented so as to avoid the minor third interval that was created to enable minor tonal music.

[engelbach]

Originally Posted by alez

All,

As far as I can see, from a theory perspective and also from Jazz Oud's ideas on chord tension vs key tension, that major 6th has all the wrong ingredients: it's a tritone away from the third of the chord and it's not even diatonic to the key. Yet there it is, present on a very significant % of classic jazz standards in minor keys, and it even has a tonic function! And then IV in minor rarely comes as m6, despite the fact that it's subdominant function and its major 6th is diatonic to the key.

I think it's all pretty weird.

Isn't it only weird from the perspective that the "normal" key in music is major? A major key has easily defined, consistent boundaries of consonance and tension. Whereas isn't the whole idea of a minor key tension bordering on instability?

In a natural minor key, in which Im7 is the tonic, the dominant is not diatonic either. In fact, it's only the presence of the dominant that creates the natural minor; otherwise, all we have is a major key named for its sixth degree.

The harmonic minor tries to solve this by incorporating the leading tone in place of the minor 7 to use in the dominant. But it isn't consistent with our major-key-based system of notating key signatures. Nor is the melodic minor.

But of course, if we take as the "normal" minor key the major key with just the third flatted — the melodic minor — and abandon the relative major key signature and adopt the parallel major key signature with a flatted third, the m6 as tonic is diatonic.

Rather than dissolve in confused madness, I think it makes sense to simply think of minor as three keys in one — a trinity — that takes on the characteristics of one or another of the three depending on the context. This thinking of them as three keys in one is to me preferable to thinking of the three as scales.

P.S. I do often see the IV played as a m6, especially in a minor blues.

PPS. I miss your point about the tritone. A tritone exists in a half-diminished and major #11 chord as well as in a dominant, so why is its existence in a minor 6 chord something strange — especially as enharmonically a m6 and half-diminished are the same?

[Ken Valentino]

Key Chords with tritones in them can work, but there needs to be something with bigger issues beforehand. For instance using augmented on the V is one option. If voiced right it can resolve to m6 dom7 or maj7(#11).

It's easy to get stuck in thinking a certain type of chord will always be resolved or tense. I figure if a major chord can even sound tense then this line of thinking doesn't hold up.

These chords with tritones in them are kind of middle ground for me. They could be tension chords or Key chords depending on the circumstances.

[jazz oud]

I think that it clarifies things to think about what the alternatives are:

m7
M7
m6

m6 can be immediately ruled out, the half-step above the 5th is just too dissonant and unstable, plus it suggests the IVm so strongly that function is obscured.

M7 works, but is more dissonant with the tonic than M6 and won't work if the melody is the root (often the case in minor).

m7 is unstable, partly because the natural occurrence of m7 is as a ii7 chord and it makes us expect to some extent that we will hear a ii7 V7 to the key of IV. Obviously this tendency isn't set in stone (modal situations in particular can break the expectation), but in tonal situations there is a functional conflict.

so, M6 is the most stable out of the alternatives, the tritone is not a big deal since the context makes it clear that we are not hearing 7 and 3.

[michaelsorg]

I think you have to ask the question: how did this chord arise, and of course, you can say that it can be derived from one scale or the other, but it's more about the sound of the chord than any other factor, and the style and density of the harmony. The chord was first heard in Romantic music, then more extensively in Impressionist music with its lush harmonies. In short, it wasn't invented by jazzers. When you extend harmony into the realm of 7th and 9th chords (not only as suspensions or appogiaturas, as was previously the case) then you have to find an extension for the minor chord. If you take the min seventh, you end up with a sound that is less minor in character because it contains the major chord within it. As was mentioned in the case of min (maj 7), you have the augmented chord, fairly dissonant; a great tool in specific circumstances, but often not suitable as tonic for the reasons already mentioned by jazz oud. The m6, as inversion of the already familiar half-diminished, was adopted as the most usable extension for minor, at least as far as passion, mystery, and some tension were to be expressed. The m7 or m9 chord has a majestic sweeping sound and can be intoned with just intonation, making it a very consonant combination in comparison.

[alez]

Great posts as usual. Thank you.

Originally Posted by michaelsorg

When you extend harmony into the realm of 7th and 9th chords (not only as suspensions or appogiaturas, as was previously the case) then you have to find an extension for the minor chord.

Ah! After reading Jazz Oud's "options" post I was think well, if none really work, why extend the triad at all? I really liked your explanation throughout, thanks.

[michaelsorg]

Originally Posted by alez

Great posts as usual. Thank you.


Ah! After reading Jazz Oud's "options" post I was think well, if none really work, why extend the triad at all? I really liked your explanation throughout, thanks.

Well, I guess I didn't really finish what I was going to say about harmonic density. If your going along playing 9th and 13th chords (typical in jazz) and you suddenly land on a major or minor triad, the sound collapses, the voice leading weakens, and the style is destroyed, in some cases. The minor chord holds out better than the major, and either one is OK if you add the 2nd (or 9th). But the minor 6 chord and especially the min 6 9 chord have become a very ingrained part of the vocabulary. Think about a Cmin6 9. Put C in the bass - start on Eb and go up in 4ths: Eb - A (aug 4th) - D. That's the same 3 note shell voicing you use for F13 and B7#9, sometimes for Am7b5. You can keep extending that voicing in 4ths: Eb - A - D - G - C . That works for any of those chords: a fat, harmonically dense sound.

[engelbach]

Originally Posted by michaelsorg

Think about a Cmin6 9. Put C in the bass - start on Eb and go up in 4ths: Eb - A (aug 4th) - D. That's the same 3 note shell voicing you use for F13 and B7#9, sometimes for Am7b5.

I call that voicing the Everything Chord.

Depending on the root, the same three-note chord can be part of a Major7#11, 7#9, 13, minor 6, half-diminished, or diminished.

Your point about harmonic richness is well taken.

[JonR]

Originally Posted by Ken Valentino

These chords with tritones in them are kind of middle ground for me. They could be tension chords or Key chords depending on the circumstances.

Very true.
Context is the difference between hearing (and accepting) a min6 - or m7b5 - chord as either tonic, subdominant (iv or ii), or even dominant (as vii in major, or rootless V9).
Of course, inversion makes a difference to the tonic sound. While Am6 might sound fine as tonic in A minor (albeit slightly mysterious), I doubt F#m7b5 would (ie F# in bass).

Likewise (I guess) the issue of the lydian tonic, with its tritone between root and #4. (In that case, I'd say other more consonant intervals in the chord over-ride its dissonance - as with a plain maj7, in fact.)

[Ken Valentino]

Originally Posted by JonR

Very true.
Context is the difference between hearing (and accepting) a min6 - or m7b5 - chord as either tonic, subdominant (iv or ii), or even dominant (as vii in major, or rootless V9).
Of course, inversion makes a difference to the tonic sound. While Am6 might sound fine as tonic in A minor (albeit slightly mysterious), I doubt F#m7b5 would (ie F# in bass).

Likewise (I guess) the issue of the lydian tonic, with its tritone between root and #4. (In that case, I'd say other more consonant intervals in the chord over-ride its dissonance - as with a plain maj7, in fact.)

That sounds right on to me. Thanks JonR

[JoeB]

Originally Posted by michaelsorg

Think about a Cmin6 9. Put C in the bass - start on Eb and go up in 4ths: Eb - A (aug 4th) - D. That's the same 3 note shell voicing you use for F13 and B7#9, sometimes for Am7b5. You can keep extending that voicing in 4ths: Eb - A - D - G - C . That works for any of those chords: a fat, harmonically dense sound.

These 3 and 4 note voicings work well on guitar. I've added an initial page of 4 note voicings to the II-V-I Tutor and will eventually add other voicings and integrate it better with the rest of the site.

The common fingerings result in a nice mixture of rooted and rootless chords. One way I like to organize them is as chords built off of the dominant arpeggio along with the tritone sub. In C Major for example we have:

G13 (rootless)
Bm11b5 (rooted)
Dm69 (rootless)
Fmaj7#11 (rooted)
Db7#5#9 (rootless)

[Fred]

JoeB,

E7(b9)sus (rooted)?

[JoeB]

Originally Posted by Fred

JoeB,

E7(b9)sus (rooted)?

Nice Fred, thanks.

I would label it Esusb9 since there is no b7 in the voicing, which is how some label it anyway even if the b7 is included. To summarize without having to go to the tutor site and translate harmonic function, for these examples I'm voicing using the notes A, B, E, and F.

I will add this to my charts.