Chord substitutions

[Boston Joe]

If you've got four beats of a 7th chord and want to break it up a bit, play the half-diminished of the third of the original chord - eg D7 F#-7b5. In that context, the half-dim chord actually sounds like D9.

You can do all kinds of stuff on dominant chords like that. If you play a half-dim on the #11, you get the #11, 7, b13, and 3. So you could do your half dim on the 3 to get the vanilla 9 sound, then move it up a whole step and get a nice altered sound. It'd basically be a tritone sub, but I think of it as a half-dim on the b5.

[joe2758]

here's that vid I said I was planning on making

[Boston Joe]

Good stuff, Joe.

[BigDaddyLoveHandles]

You can do all kinds of stuff on dominant chords like that. If you play a half-dim on the #11, you get the #11, 7, b13, and 3. So you could do your half dim on the 3 to get the vanilla 9 sound, then move it up a whole step and get a nice altered sound. It'd basically be a tritone sub, but I think of it as a half-dim on the b5.

Confused!

Take C7.

The half dim on the 3rd is: E G Bd D -- C9(no root) check!

The half dim on the #11 is: F# A C E -- (#11 13 root 3) - not what you wrote.

What you wrote, #11 7 (I assume b7) b13 and 3 would be F# Bb Ab E. Maybe a F#9(no 5)?

[christianm77]

If wanted an altered dom sound using a half dim chord I would build the chord a whole step below the root of the dominant. So - for G7alt, Fm7b5.

I also tend to view these subs as minor 6th subs. If we are talking about D7, F#m7b5 is the same thing as Am6. Some people might find it easier to think of 'm6 a fifth up', rather than 'm7b5 a maj 3rd up.'

This is an extremely venerable substitution, and can also be used as a gateway into melodic minor harmony, just by playing minor key phrases on that sub.

If you tritone sub a Am6, you get Ebm6, which is a half step above the dominant. That's the G altered, right? Also, the same as Fm7b5.

Add in a maj7 on the m6 chords and you are there. You could add a natural 2nd on the m7b5 chords, but I find that harder to get my head around. Probably worth practicing both.

[Boston Joe]

I also tend to view these subs as minor 6th subs. If we are talking about D7, F#m7b5 is the same thing as Am6. Some people might find it easier to think of 'm6 a fifth up', rather than 'm7b5 a maj 3rd up.'

I would not be one of those people, although I'm doing my best to see it both ways.

Likewise some people like to think of a m6 a half step up from the root of a dominant chord, whereas I see that as a tritone sub. (e.g Db9 against a G7 rather than Abm6.) It doesn't matter so much since I'm rarely playing the root anyway. (My ensemble leader (and bassist) likes to say, "Same chord, different root," when the subject of tritone subs comes up.)

[joe2758]

Joe, Barry Harris thinks like you. So Abm6 sub for G7, he would say he's using the important minor of the tritone sub. That's sort of the reason as to the why; the method to grab it with less thinking is "a half step above." so yeah, both ways

[Boston Joe]

Joe, Barry Harris thinks like you. So Abm6 sub for G7, he would say he's using the important minor of the tritone sub. That's sort of the reason as to the why; the method to grab it with less thinking is "a half step above." so yeah, both ways

I think my way of grabbing it with the least thinking would be to think of it as a G7b9/b13 (because I have a good sense of where chord tones are relative to roots), But thinking of it as a Db9 or an Ab-6 opens up other ways of looking at it.

[JonR]

I was wondering if there were any chord substitutions you could use to "jazz up" a song that has really basic chords. I know about chord extensions (ex. Changing a G7, C7, F chord progression to G9, C13, Fmaj7) but, if there are some basic rules to substituting chord or even common chord substitutions please share them here! Thx a lot in advance

Firstly be aware of functional subs. There are really only three harmonic functions: tonic, dominant, subdominant (aka pre-dominant).
Tonic: I, vi, iii
Dominant: V, vii
Subdominant: IV, ii

So, in key of F, you could replace F with Dm or Am, C with Edim, and Bb with Gm. IV and ii are the most interchangeable. The "tonic" functions don't work the same way though. Especially the iii. If you have an F major sequence with an Am already present, replacing it with F is likely to sound clunky at best. But replacing F with Am can be cool, producing an intriguing lack of resolution (essentially removing the root from an Fmaj7).

Beyond that - there's two things to think about:

1. Harmonising the melody. Any alterations or additions to the chords still have to fit the melody. This needn't limit you too much (especially in jazz!) but needs bearing in mind. (If you don't have a melody: get one!)

2. Voice-leading. Generally, chord substitutions are about introducing more interesting voice-leading, usually chromatic (out of key and by half-step)

So, taking your G7-C7-F...

1. Tritone subs. This is replacing any V7 chord with a bII7 (root a half-step above the next chord). You keep the crucial inner tritone between 3rd and 7th, while the other two notes lead down via half-step to the following chord. So either - or both - of those V7 chords could be replaced with a tritone sub:
G7-Gb7-F;
Db7-C7-F;
Db7-Gb7-F.

2. Dim7 subs. This is replacing any V7 with a dim7 built on its 3rd. IOW, using the viidim7 of the next chord. (viidim7-I is a conventional minor key cadence, which we can borrow for major.)
Again, three options with your sequence:
G7-Edim7-F
Bdim7-C7-F
Bdim7-Edim7-F
Of course, dim7s are symmetrical so you could call those two by three other names if it helps. Eg, they descend in half-steps, so Fdim7-Edim7-F might seem more logical, but really it's the same chords. You hear that in blues turnarounds all the time, usually with F7 - or even F#dim7 - in front.)

3. Adding min7s. Any V7 can be (and usually is in jazz!) preceded with a ii7. So your G7-C7-F would become:
Dm7-G7-Gm7-C7-F. Which in turn can become:

Dm7-Db7-Gm7-Gb7-F;
Abm7-Db7-Dbm7-Gb7-F
etc.

4. Turning major key ii-Vs into minor key ii-Vs. This means using altered V7s, and half-dim ii chords:
Dm7b5-G7b9-Gm7b5-C7b9-F
7b9 is one of the commonest alterations, but you could also have 7#9, 7b5b9, 7#5#9, etc.

When you use a tritone sub for an altered V7, you essentially keep a lot of the same notes - ie., you don't replace it with another altered V7, but with a "lydian dominant".
G7#5#9 (or b5b9) would be replaced with Db7#11 (or Db9#11 or Db13#11). If you look at the notes in the chords, you find they are all from the same 7-note scale. So the only real difference between the V7alt and its tritone sub is the bass note.

5. The backdoor progression. This is a bVII leading to I, usually preceded by its own ii chord. It has a quite different character to a V7 and the other subs for a V7, so should perhaps not be considered a V7 sub at all.
Eg, instead of Gm7-C7-F, you'd have Bbm7-Eb7-F. Bbm7-Eb7 is really an embellishment of a plain Bbm, or Bbm6, the minor iv chord; so this is really a type of "minor plagal cadence" (iv-I), not really a V-I at all.
It might also be harder to get this to harmonise with an existing melody. Still, it's a cool effect! Just look at how Eb9 (Bbm/Eb, more or less) moves to Fmaj7 (Am/F): 3 descending half-steps to balance the ascending whole step.

6. So if we can replace C7 (going to F) with Gb7 and Eb7 - how about the other dim7-linked dom7? A7? IOW, all four of those dom7 chords can be replaced with the same dim7: Edim7/Gdim7/Bbdim7/C#dim7. So can A7 lead to F? Yes - sort of.
A7 is the V of the relative minor, Dm, so going to F is a kind of deceptive cadence. And if you use the normal ii in D minor, Em7b5, before A7, that's like a rootless C9. Em7b5-A7: we expect that to lead to Dm; so resolving to F is a surprise, but still somehow logical (add a b9 to A7 to make it even more logical...).

7. Other cool stuff... Extending tritone subs further back leads to the "Tadd Dameron turnaround", which evolved into the famous "Coltrane changes".https://en.wikipedia.org/wiki/Tadd_Dameron_turnaround
So if your G7-C7-F was extended back to F-D7-G7-C7-(F) - a classic 1920s jazz turnaround - you could tritone sub all those V7s: F-Ab7-Db7-Gb7-(F). And naturally min7s could be inserted between, and even - in extreme cases - the dom7s can be turned into maj7s, which kind of changes their whole function but still works.
Again - of course - don't forget the melody (if present)! The reason jazz musicians could have so much experimental fun with turnarounds was because that was the point at which the melody had ended - there was a couple of bars before it started again, so the harmony was up for grabs.

[Boston Joe]

Great stuff Jon!

[Robertkoa]

Jon- love this list ...I am more interested in Composition but as you might imagine....your little list is a Great Resource and also amazingly clear and concise !

I read about the 'Backdoor Progression' before but there were long winded complicado explanations so I just didn't bother lol.
NOW - I get it....in Rock of course a bVII
or bVII7 Chord is very common as a way to get back to a I or i -
( and adding IV of bVII also ).

I really like your Applied Theory Clear Condensed Concept etc.

You can't do a Book and call it "Practical Music Theory for Dummies " because it is not flattering to the Buyer...lol.

"Practical Music Theory for Near Geniuses" maybe...?

Whether you do a Book or not-

I Bookmarked this and look forward to some more of this stuff from you.

Thanks for the Post...great stuff.

[christianm77]

I missed your post for some reason Jon, great list.

If anyone is interested this is a document I've been working up for students (still a work in progress) - a lot of overlap with what you are saying.

https://www.dropbox.com/s/7tvc1av2nr...heets.pdf?dl=0

[Boston Joe]

Nice document, Christian. I've been keeping something similar in my OneNote notebook. A "quick and dirty" guide to chord subs.

[Thecytochromec]

Awesome thread. I'm sub'd

[edh]

Here! Here! Xclnt Thread

[JonR]

Jon- love this list ...I am more interested in Composition but as you might imagine....your little list is a Great Resource and also amazingly clear and concise !

I read about the 'Backdoor Progression' before but there were long winded complicado explanations so I just didn't bother lol.
NOW - I get it....in Rock of course a bVII
or bVII7 Chord is very common as a way to get back to a I or i -
( and adding IV of bVII also ).

In rock, it's rather different. For a start, the chords are almost never more than triads. So a bVII chord typically just moves up by whole step - in parallel blocks - to the I.
It's borrowed from the parallel minor, of course - like the jazz bVII - but the latter really works by its contrary voice-leading: those descending half-steps which balance the ascending whole steps. (Rock is really not interested in that kind of sophistication - it would tend to come under the heading of "cheese"... )

So the 3-chord equivalent in rock is either bVI-bVII-I, or the mixolydian "double plagal" cadence, bVII-IV-I (analysable as IV/IV - IV - I.)
As I think you're saying, you might also get bIII-bVII-I (bIII being IV of bVII, if you follow me...).
Certainly, rock really loves the plagal cadence, in secondary or primary form, much more than the perfect or authentic cadence. V-I is just so cheesy, maan! IV-I is way cooler. You only have to compare I-IV-V-I with I-V-IV-I... no contest!

You can't do a Book and call it "Practical Music Theory for Dummies " because it is not flattering to the Buyer...lol.

The Dummies publishers don't seem to have had that problem... But of course they have copyrighted the concept...

"Practical Music Theory for Near Geniuses" maybe...?

Yes, but then "near geniuses" don't need books do they? Imagine the unspoken conversation between book buyer and shop assistant.... "Hmmm, he can't be a real genius if he's buying this book... he's kidding himself..." "Actually it's not for me, it's for a friend, ahem...." Of course, amazon disposes of such old-fashioned social awkwardness, but even so, a book designed for "near geniuses" is going to seem way too advanced for most. That's the appeal of the dummies books: they use humour to make you unashamed of your ignorance.

I Bookmarked this and look forward to some more of this stuff from you.

Thanks for the Post...great stuff.

Thanks - your appreciation is appreciated.

[christianm77]

I'd totally buy a book called Practical Music Theory for Dummies. If nothing else, it might teach me some ways of teaching, but in all likelyhood I'd learn a few things!

I think as soon as you think of yourself as an expert (or even not a Dummy) in any area, you close yourself off.

[JonR]

I think as soon as you think of yourself as an expert (or even not a Dummy) in any area, you close yourself off.

Exactly. If you think of yourself as "advanced" or "expert", you believe you either know it all, or you know as much as you'll ever need to know. Either way, that ought to be a sign that you don't.