Easy question (I think) about "alt" chords

[JonR]

Originally Posted by kingfisher

If you have any choice of sharp/flat 5 and sharp/flat 9, that leaves a total of 4 different choices. How do you decide which to play?

In addition to the excellent advice above, it might be worth looking at the chords either side, and how you are voicing those.

In general the altered chord and scale is designed to provide half-step transitions, especially resolving to a following tonic, or to consonant extensions on the tonic like 6 or 9.

I'd agree with the others that usually #5#9 is a good combination, but sometimes you might find b5 and/or b9 make nice moves on to following chord tones or extensions.

You can also (if it helps!) think of a 7alt chord as its tritone sub, which would be lydian dominant.
Eg, for G7alt, you could think Db7 (or Db7#11, Db9#11, Db13#11). It's all the same pool of notes (aka Ab melodic minor).

[michaelsorg]

Originally Posted by JonR

In addition to the excellent advice above, it might be worth looking at the chords either side, and how you are voicing those.

In general the altered chord and scale is designed to provide half-step transitions, especially resolving to a following tonic, or to consonant extensions on the tonic like 6 or 9.

I'd agree with the others that usually #5#9 is a good combination, but sometimes you might find b5 and/or b9 make nice moves on to following chord tones or extensions.

You can also (if it helps!) think of a 7alt chord as its tritone sub, which would be lydian dominant.
Eg, for G7alt, you could think Db7 (or Db7#11, Db9#11, Db13#11). It's all the same pool of notes (aka Ab melodic minor).

Good point, Jon. The resolution is half the gig. We get so entranced by the sounds and possibilities of the altered dominant, and don't watch where we're going sometimes, then the resolution is awkward, out_of-time, or doesn't make sense. I have my favorite diminished patterns, and always have to remember to practice how I'm going to resolve them.

[jazz oud]

Good point by JonR about considering the voice-leading of the alterations when choosing. Though I think that the m3 resolution of #9 to 5 can be very effective, especially in bluesy contexts.

While I agree that the strength of half-step resolutions is part of the appeal of altered dominants, I think we have to be careful about saying things like "the altered chord and scale is designed to provide half-step transitions". First of all, the chord and scale are not really "designed", they are more like emergent properties of the tonal system. At best, they are evolved from a series of practices.

More importantly, I think the reason for most alterations is purely about the sound of the alteration, and not necessarily how it resolves. With the exception of the b5/#11, the alterations are borrowed from the parallel minor, making their presence about modal interchange from a harmonic standpoint. The b5 is sort of reverse-engineered from the practice of tritone substitution (itself a practice reverse-engineered from the use of Augmented 6th chords).

The half-step resolution is part of the reason why alterations are effective, and kind of a bonus byproduct. But it's not as if an altered dominant is somehow an straight-up improvement over a diatonic dominant, it's just a different sound. The sound is the main thing.

[kingfisher]

Originally Posted by Tarquin1986

On V7#5 and V7b5 chords I often use the whole tone scale. That includes a natural 9 though.

I've not been taught the whole-tone scale, but it seems to me that there are only two of them: one that starts on C and one that starts on C#. Am I right?

If so, how would you know which scale to use over your #5 or flat 5 chords?

[jazz oud]

Originally Posted by kingfisher

I've not been taught the whole-tone scale, but it seems to me that there are only two of them: one that starts on C and one that starts on C#. Am I right?

If so, how would you know which scale to use over your #5 or flat 5 chords?

I'm sure if you think about this for a moment, you can figure this one out. Think about the notes in the chord, and see which scale has those notes in it.

[engelbach]

Originally Posted by jazz oud

More importantly, I think the reason for most alterations is purely about the sound of the alteration, and not necessarily how it resolves.

Another perceptive post, J.O. An alt chord is often a punctuation rather than part of a logical voice-leading progression.

However, it fits right in with voice leading in a progression that includes chromatically descending tritone subs.

[jazz oud]

Originally Posted by engelbach

Another perceptive post, J.O. An alt chord is often a punctuation rather than part of a logical voice-leading progression.

However, it fits right in with voice leading in a progression that includes chromatically descending tritone subs.

Aw, shucks, Jer. The point about voice leading is a good one for sure, my comment was mostly about how we talk about these things. JonR's statements were perfectly in line with how a pro might think about it, my concern is that the person asking the question might misunderstand it because he doesn't have the same base of knowledge.

Sometimes things seem so obvious that we take them for granted, but we need to keep in mind that these things might not be so obvious to a student. I've seen too many students confused or misled by statements that assume a level of understanding that they may not have.

Even something as innocuous as "tritone subs are hip" can lead a student to internalize a false dichotomy of "hip chords" vs "not-hip chords", without the baseline understanding that whatever is "hip" is really what the most musical thing at a particular moment might be. A tritone sub can be corny, a straight maj7 can be the most perfectly hip thing, it depends on the context and the player.

[kingfisher]

OK, so now another newbie observation about "alt" chords. Last night I tried using the combination of a flat 5 and a sharp 9 where it called for "G7alt."

Of course, you guys know what I ended up with, which was nothing more nor less than a G half-diminished chord.

So here's my next question: Is that considered an "alt" chord? It uses a combination of a flat or sharp 5 and a flat or sharp 9, but it's a regular chord that is used in many, many songs and never labelled "alt" in that context.

The corrollary question is this: Is the flat 5 sharp 9 "not permissible" (or at least not what the composer intended) when he/she asked for an "alt" chord? In other words, should a half-diminished chord essentially never be used when an "alt" chord is called for?

Thanks.

[jazz oud]

You need to include the 3rd for it to be a 7alt chord.

R 3 b5 b7 #9 = 7alt
R b3 b5 b7 = ø7

[engelbach]

Originally Posted by kingfisher

OK, so now another newbie observation about "alt" chords. Last night I tried using the combination of a flat 5 and a sharp 9 where it called for "G7alt."

Of course, you guys know what I ended up with, which was nothing more nor less than a G half-diminished chord.

So here's my next question: Is that considered an "alt" chord? It uses a combination of a flat or sharp 5 and a flat or sharp 9, but it's a regular chord that is used in many, many songs and never labelled "alt" in that context.

The corrollary question is this: Is the flat 5 sharp 9 "not permissible" (or at least not what the composer intended) when he/she asked for an "alt" chord? In other words, should a half-diminished chord essentially never be used when an "alt" chord is called for?

Thanks.

Your chord would only be a G half-diminished if you left out the major 3rd, B natural.

I think the most common voicings for a 7alt don't include the b5, but it's perfectly permissible to include it. Here are two possible voicings (out of many) for a G7alt with a b5:

(G) F B Eb Bb Db — includes b13, Eb

(G) F Bb B Eb Ab Db — includes b9, Ab, and B13, Eb

No. A half-dim isn't an Alt chord. An Alt chord is by definition a dominant, V7. A half-diminished is usually a IIm7b5.

A 7alt is often a tritone sub for a V13#11. Db13#11 and G7alt are identical. The name just depends upon whether a Db or a G is played as the root.

=======================

Now, this is interesting: If you play a half-dim, but use the root of the dominant, you've got a dominant with a suspended 4th: V7b9sus, also sometimes called a Phrygian Chord — C G Bb Db F.

It's weaker than a normal dominant because it lacks the leading tone, the third (E) of the dominant. It contains the fourth (F), which is the tonic of the next chord, FΔ or Fm.

=======================

Chords don't automatically indicate specific scales — one can play different scales against the same chord — but a 7alt does suggest that a specific scale be used, even if they're not played in the chord, the so-called "alt scale": 1 b2 [b9] b3 [#9, b10] 3 b4 b5 b7.

(The "alt scale" is the melodic minor of the note a half step above. So a G alt scale is Ab melodic minor.)

One isn't locked into this, by any means. One could play a natural 5, for example.

EDIT: Some of this post duplicates info contained in other posts above.

[engelbach]

Originally Posted by jazz oud

You need to include the 3rd for it to be a 7alt chord.

R 3 b5 b7 #9 = 7alt
R b3 b5 b7 = ø7

We posted at the same time ...

[kingfisher]

Thanks very much. Now that I've read your answers, it seems pretty obvious.

I really appreciate the patience shown by the experienced guys on this forum toward a newbie like me. Everybody has to start somewhere, right? Maybe in a few years I'll be able to help out another newbie the way you have been helping me.

[Music997]

The #5 and the #9 Alt chord is commonly used.

The voicings for a C7 Alt chord would be: E , G#, B-flat and D#

You always want the 3rd and 7th in your voicings.

[Jeff Brent]

rootless dominant tritone enharmonics

G7#5#9	= D♭13
G13	= D♭7#5#9

G7#5♭9	= D♭9
G9	= D♭7#5♭9

G7#9	= D♭13♭9
G13♭9	= D♭7#9

G7♭5♭9	= D♭7
G7♭9	= D♭7♭9

G9#5	= D♭9#5

G13#9	= D♭13#9

[JonR]

Originally Posted by jazz oud

While I agree that the strength of half-step resolutions is part of the appeal of altered dominants, I think we have to be careful about saying things like "the altered chord and scale is designed to provide half-step transitions". First of all, the chord and scale are not really "designed", they are more like emergent properties of the tonal system. At best, they are evolved from a series of practices.

Sure. When I said "designed" I didn't mean somebody designed them. (Bad choice of word )

But I do firmly believe that the evolution of the chord - that series of practices - was about those half-step resolutions. At least that's the way the chord (and the scale which is essentially a collection of all the possible chord tones) makes sense to me. (I really didn't get the altered chord/scale until I realised that.)

Of course, the sound of the the alteration(s) on the chord itself - its sonority and colour - is an important aspect. (In particular, IMO, that bluesy sound of the #9 above the M3.)

But IMO that sound is merely the sum total of all the potential voice-leading options.
It's a kind of "superfunctional dominant" (yes I just made that up ).
An ordinary dom7 only has two leading notes, 3 and 7. A 7alt has 5 or 6.

Originally Posted by jazz oud

The b5 is sort of reverse-engineered from the practice of tritone substitution (itself a practice reverse-engineered from the use of Augmented 6th chords).

Right. The tritone sub is the key, IMO. A 7alt is the same chord, essentially, as a lydian dominant bII7. (The scale and all the possible chord tones are the same.)
Obviously a bII7 has a ton of half-step moves (not only downward); that would be the reason for choosing it. In that sense, the V7alt just gives it a different bass note.
(I realise this might seem a crude approach to it, but it works for me; I don't see a need to make it any more subtle .)

Originally Posted by jazz oud

The half-step resolution is part of the reason why alterations are effective, and kind of a bonus byproduct. But it's not as if an altered dominant is somehow an straight-up improvement over a diatonic dominant, it's just a different sound. The sound is the main thing.

Sure.
IMO it can be argued it is "a straight-up improvement over a diatonic dominant", if we regard additional dissonance and additional half-step resolutions as "improvements".
But of course we don't always want that kind of increased tension.