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  #1  
Old 09-17-2013, 09:29 AM
jasperguitar jasperguitar is offline
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Default Related chords, same notes, use/understanding????

I got goofing, as I do ...

I played an Am6 chord.

A, C, E, F #

Huum... when I look at it from the low E string ..

I have F# min 7 flat 5

same notes ...

then I got looking at the gm7
G, B flat, D, F

and that is also the B flat 6

..

I got wondering how all this plays into playing, or using ..

The B flat 6 ... and the G m 7 .... . well, Gm is the relative m or the
B flat Maj scale... so ??

But the other one ?

the minor 6 and the minor 7 flat 5 ?

All the Doctors of music theory can jump on this one

Thanks...
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  #2  
Old 09-17-2013, 10:10 AM
JonPR JonPR is offline
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Quote:
Originally Posted by jasperguitar View Post
I got goofing, as I do ...

I played an Am6 chord.

A, C, E, F #

Huum... when I look at it from the low E string ..

I have F# min 7 flat 5

same notes ...

then I got looking at the gm7
G, B flat, D, F

and that is also the B flat 6

..

I got wondering how all this plays into playing, or using ..

The B flat 6 ... and the G m 7 .... . well, Gm is the relative m or the
B flat Maj scale... so ??

But the other one ?

the minor 6 and the minor 7 flat 5 ?

All the Doctors of music theory can jump on this one

Thanks...
No big deal here.
The m6/m7b5 distinction in jazz is largely one of fashion. In older jazz charts (typically in old printed music), you'll see m6 chords all the time, never the m7b5 inversion, even when the 6th is in the bass. IOW, a chord voiced F# A C E will still be called "Am6". But in more recent charts, such as jazz real books, the "m7b5" version is much more common.

One aspect of the distinction is that m6 chords are often minor ivs in major keys, typically following the major IV, and probably resolving back to I.
Half-dim chords OTOH (m7b5) get used as ii chords in minor keys, resolving to V then I.
Eg, A - Am6 - E, in key of E major
Or F#m7b5 - B7 - Em in key of E minor (or sometimes in E major)

The former is a common cliche sequence, and even in modern jazz, the chord would be called "Am6" in that context.
But when it moves to a B7 chord, then (in later jazz anyway) it would be labelled "F#m7b5".

The minor iv chord is often further translated (in jazz) into a bVII "backdoor" chord.
Eg, (key of E major again) A - D9 - Emaj7. D9 is Am6/D (or F#m7b5/D of course)

With the m7/maj6 distinction, again there is an old convention (classical I think) whereby the chord is always considered to be a min7 chord, regardless of inversion. IOW, min7 chords date way back to early classical music. Adding 6ths to a major triad is more a recent thing, however - it still happened in classical music first, but it became standard in pop and jazz, as a kind of cheesy embellishment of a major triad.
There's a jazz harmony convention that I and IV major chords are maj7s by default, except when the melody note is the root; in that case they become 6th chords.

As in a minor key, the IV and ii in a major key have the same "pre-dominant" function (leading to V). So Bb6 and Gm7 are interchangeable for leading to C7 in key of F major.
Jazz theory tends to prefer to think in "ii-V" than "IV-V", so in that context would choose "Gm7" (maybe even if Bb was the bass note).
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Old 09-18-2013, 07:09 PM
DupleMeter DupleMeter is offline
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It's really all about context.

The same thing happens with Maj6 and Min7 chords, for instance:

CMaj6: C E G A
Am7: A C E G

How do you name that in a song?? It all depends on context. In the end it doesn't matter because your ear will hear it in context and tell you whether it's a Maj6 or Min7. Theory is just a way of explaining what we hear, and what we hear changes based on how we hear it (context). Hence, we have multiple names for the same note clusters...each name based upon the context in which we perceive them.
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  #4  
Old 09-19-2013, 03:50 AM
macmanmatty macmanmatty is offline
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Quote:
Originally Posted by jasperguitar View Post
I got goofing, as I do ...

I played an Am6 chord.

A, C, E, F #

Huum... when I look at it from the low E string ..

I have F# min 7 flat 5

same notes ...

then I got looking at the gm7
G, B flat, D, F

and that is also the B flat 6

..

I got wondering how all this plays into playing, or using ..

The B flat 6 ... and the G m 7 .... . well, Gm is the relative m or the
B flat Maj scale... so ??

But the other one ?

the minor 6 and the minor 7 flat 5 ?

All the Doctors of music theory can jump on this one

Thanks...
Shouldn't an Am6th be A C E F?? Using the 6th of the A minor scale rather than the 6th of the A Major scale because the chord is minor? And wouldn't that not also be an F Maj7th chord??
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  #5  
Old 09-19-2013, 06:01 AM
JonPR JonPR is offline
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Quote:
Originally Posted by macmanmatty View Post
Shouldn't an Am6th be A C E F?? Using the 6th of the A minor scale rather than the 6th of the A Major scale because the chord is minor? And wouldn't that not also be an F Maj7th chord??
The figure "6" as a chord extension always means a major 6th, whether the chord is major or minor.
A6 = A C# E F#
Am6 = A C E F#

A C E F would be "Amb6", and is not a chord you see very often. Mainly because - as you say - it's usually interpreted as an Fmaj7. Even with the A on the bottom, it sounds more like an F-root chord (in 1st inversion) than an A-root chord.

Occasionally you'll see minor sequences - known as a "line cliche" - with chromatic lines up from the 5th or down to it; in that case, there'll be an F added at some point to the Am chord. Eg:
Am - Amb6 - Am6 - Am7
But in those cases you're probably more likely to see it written as:
Am - Am(#5) - Am6 - Am7
Or
Am - F/A - Am6 - Am7
(It the E was included in the F/A, of course it would be Fmaj7/A. But it would be unusual to voice the F above the E, because of its dissonance. That's why Amb6 chords are rare, except in this kind of passing role.)

BTW, when building chords, we don't take the extensions from a specific scale. Chord symbols are based simply on the most common kinds of added notes. The commonest extensions get the shortest names, so that the language is a handy shorthand.

It so happens that the most common extensions all come from the major scale of the root, with one important exception: the 7th. The most common kind of 7th is a minor 7th (10 half-steps up from the root). So a plain "7" on a chord is always a minor 7th. The rarer major 7th (11 half-steps) is labelled "maj". Eg, the following chords all have a G#:
Amaj7
Am(maj7)
Amaj9 (7th implied)
Amaj13 (7th implied)
The following chords all have a G:
A7
Am7
A9 (7th implied)
A13 (7th implied)
Am7b5

The exception is Adim7 which has a Gb - a diminished 7th interval. IOW, while "maj" qualifies the "7" by raising it, "dim" qualifies the "7" by lowering it.
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Last edited by JonPR; 09-19-2013 at 06:11 AM.
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  #6  
Old 09-19-2013, 05:06 PM
Howard Klepper Howard Klepper is offline
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JonPR is, as usual, right and very informative. [I dunno about the Maj6 being a "cheezy" chord, tho {;->]

I'm going to play a hunch that he might have told the OP more than he wanted to know (or at least more than he is digesting at one meal), and give a more simplified answer.

A min7b5 is treated as one of two different chords, in two different keys, depending on what follows it. First, it can be a chord with its root on the second degree of a scale: a iim7 chord with a b5, e.g., an F#m7b5 that goes to a B7 is a ii chord in E minor (or possibly Emajor; the b5 indicates--but does not necessitate--that it be E minor).

Second, the m7b5 can be a chord built on the 7th degree of a major scale, in which case it is a dominant chord in that key, e.g., an F#m7b5 is a dominant chord in G major. It can be a V7 chord in the key of G major, or a iim6 leading to the V7 in G major. In this case the F#m7b5 is either is a D9 with root omitted, or an Am6 that moves to some form of D7. Wait--I said above that a min7b5 is one of just two different chords, right? I was simplifying, and treating the ii6/V7 as all being functionally the dominant chord. To break that down a bit further, if an F#m7b5 goes directly to G major it was a D9; if it goes to a D7 (or a D7 with extensions), it was an Am6.

The main point is that a min7b5 can indicate one of two different keys, and you don't know which until you see what follows it.
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Last edited by Howard Klepper; 09-19-2013 at 11:52 PM.
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Old 09-19-2013, 07:14 PM
athair athair is offline
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In a book i´ve recently read, the only extensions allowed within the minor degrees of a given major scale (II, III, VI) are the following:

II:4/11 & 9th.

III:4/11th.

VI:4/11th & 9th.

The autor (Erico Herrera) claims that extension notes should be avoided whenever they make a flat 9th interval with any note belonging to the cuatriad structure of the given degree: so, for instance, a 4th is not allowed within degree I, because it yields a flat 9th degree with the (major) 3rd; a 6th/13th is not allowed within a degree VI, because it yields a flat 9th interval with the 5th...and so on.

I am not sure if such a principle is a generalized one in harmony texts (Herrera´s book is called Teoría Musical y Armonía Moderna...that is in english "Modern music theory and harmony (I)", although i don´t even know whether there exist english version at all...)

Later on, the same type of analysis extends over minor scales...etc.

Personally, i often find helpful not to work with chords but either with intervals or triads (in the book there is also a split of a given degree-chord into the so called cuatriad, on one hand, and the superstructure, that is the available extensions, on the other). In such a context, chords (or scale degree-chords) would mean (elementary) analytic frameworks (of great help when trying out some voice-leading approach, but not exclusively...)...

Greetings!

Last edited by athair; 09-20-2013 at 12:30 AM.
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  #8  
Old 09-20-2013, 04:20 AM
JonPR JonPR is offline
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Quote:
Originally Posted by Howard Klepper View Post
JonPR is, as usual, right and very informative. [I dunno about the Maj6 being a "cheezy" chord, tho {;->]
The best description of the sound of a 6th chord that I've read is "smug" - and I think that came from a jazz musician.

I like 6th chords myself - I think of them as "warm" more than "smug" - but for me the image of an insincere entertainer's grin as I play it is irresistible...
Quote:
Originally Posted by Howard Klepper View Post
A min7b5 is treated as one of two different chords, in two different keys, depending on what follows it. First, it can be a chord with its root on the second degree of a scale: a iim7 chord with a b5, e.g., an F#m7b5 that goes to a B7 is a ii chord in E minor (or possibly Emajor; the b5 indicates--but does not necessitate--that it be E minor).
Yes.
Quote:
Originally Posted by Howard Klepper View Post
Second, the m7b5 can be a chord built on the 7th degree of a major scale, in which case it is a dominant chord in that key, e.g., an F#m7b5 is a dominant chord in G major.
Well, if we're being strict with terminology, F#m7b5 (or F#dim) is the vii, or "leading tone chord", in G major.
The "dominant" chord (V) is D; with D7 as "dominant 7th" of course.
More broadly (which is what you're saying), both chords have a "dominant function", in that they resolve to G.
Quote:
Originally Posted by Howard Klepper View Post
It can be a V7 chord in the key of G major, or a iim6 leading to the V7 in G major. In this case the F#m7b5 is either is a D9 with root omitted, or an Am6 that moves to some form of D7. Wait--I said above that a min7b5 is one of just two different chords, right? I was simplifying, and treating the ii6/V7 as all being functionally the dominant chord. To break that down a bit further, if an F#m7b5 goes directly to G major it was a D9; if it goes to a D7 (or a D7 with extensions), it was an Am6.
Ah, now you're complicating it a little . (Not that I'm not probably about to do the same...)

"if an F#m7b5 goes directly to G major it was a D9" - strictly speaking, it's a rootless D9, or is seen as standing for a D9.
In theory there's no need to invoke D9 at all, because F#m7b5 - as vii - can perfectly well resolve to G in its own right.
However - in jazz and popular music - this basically never happens. One simply doesn't see vii chords in major keys. One might see rootless V9 chords (in guitar or piano), but the assumption is that the V root will be in the bass somewhere.
So I agree totally that "D9 sub" is how it's generally regarded.
You get leading tone chords in minor keys (see below), but almost never in major keys. The notion of the "rootless V7" is always invoked.

"if it goes to a D7 (or a D7 with extensions), it was an Am6." - Yes, except that rarely, if ever happens. Neither F#m7b5 nor Am6 (whatever we want to call it) would normally precede D7. What would far more likely precede D7 would be Am7 - or C6 (which is the other doppelganger chord pair of course! ).

Am6 would more likely occur as iv in E minor - which is only an inversion of the supertonic (F#m7b5) of course .

IOW, one little half-step - as in so many cases - makes all the difference.
Am7 goes to D7 because the G descends to F#; that's the significant distinction between the chords. Am6 removes that distinction, and makes it functionally resemble D7 (or a rootless D9 as you say).

...

There's similar observations (risking too much info again ) about leading tone chords in minor keys.
In this case the vii chord is unique: it's a dim triad, like the ii chord (and vii in major), but in a minor key it has a diminished 7th.
Here we see another example of the functional difference made by one little half-step. In key of A minor:
B D F A = ii chord = supertonic (pre-dominant), goes to E7, then Am
G# B D F = vii chord = leading tone chord, goes to Am
Obviously the only difference is A/G#.

If we voice the vii chord as B D F G#, we might call it "Bm6b5" - and get a similar phenomenon to the "Am6" identity of F#m7b5. But that would be similarly misleading as to its function. "Bm6b5" is not a ii chord in A minor; it's mislabelled vii chord (inverted G#dim7), which goes to Am, not E7.
(It's not even a mislabelled Bdim7, btw, which is B D F Ab, vii chord in C minor.)
IOW, the ii chord needs to have the A in it, in order to have the voice-leading down to G# - on either the V (E) or the vii (G#dim) - which then resolves back up to A.

Of course (as we know!), G#dim7 can also be seen as a rootless E7b9! But it's more common in practice to see a leading tone chord in action in a minor key. We might still like to view it as standing for V7(b9), but we certainly see more of them.
Naturally they can't be confused with ii chords in minor keys, like vii chords in major keys can (which may be one reason the latter are not used).

Apologies to the OP if he now feels like running for the hills...
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  #9  
Old 09-20-2013, 07:42 AM
DupleMeter DupleMeter is offline
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Quote:
Originally Posted by athair View Post
In a book i´ve recently read, the only extensions allowed within the minor degrees of a given major scale (II, III, VI) are the following:

II:4/11 & 9th.

III:4/11th.

VI:4/11th & 9th.

The autor (Erico Herrera) claims that extension notes should be avoided whenever they make a flat 9th interval with any note belonging to the cuatriad structure of the given degree: so, for instance, a 4th is not allowed within degree I, because it yields a flat 9th degree with the (major) 3rd; a 6th/13th is not allowed within a degree VI, because it yields a flat 9th interval with the 5th...and so on.

I am not sure if such a principle is a generalized one in harmony texts (Herrera´s book is called Teoría Musical y Armonía Moderna...that is in english "Modern music theory and harmony (I)", although i don´t even know whether there exist english version at all...)

Later on, the same type of analysis extends over minor scales...etc.

Personally, i often find helpful not to work with chords but either with intervals or triads (in the book there is also a split of a given degree-chord into the so called cuatriad, on one hand, and the superstructure, that is the available extensions, on the other). In such a context, chords (or scale degree-chords) would mean (elementary) analytic frameworks (of great help when trying out some voice-leading approach, but not exclusively...)...

Greetings!
In general tensions (9, 11, 13) are available if they are a a major 9th above a chord tone (octave and a maj 2nd). That's the rule, and there are plenty of places you can break the rule.

I've created a Modal Interchange & Available Tensions chart for my students...you can grab a copy here: http://www.stevedemott.com/wp-conten...e-tensions.pdf

I shows each chord with it's available tensions and then all the relative & parallel relationships along with which chord scale to use in each case.
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1927 Martin 00-21
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1987 Ibanez RG560
1988 Fender Fretless J Bass
1991 Washburn HB-35s
1995 Taylor 812ce
1996 Taylor 510c (custom)
1996 Taylor 422-R (Limited Edition)
1997 Taylor 810-WMB (Limited Edition)
1998 Taylor 912c (Custom)
2019 Fender Tele
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  #10  
Old 09-20-2013, 11:04 AM
athair athair is offline
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Thank you very much, Steve!! I´ll take a look at your chart!!! (quite interesting and useful subject!)
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  #11  
Old 09-21-2013, 10:44 AM
jasperguitar jasperguitar is offline
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"Huum... when I look at it from the low E string .. "

I miss wrote .. should have called the E string the 1st string, or high E string.

I'm trying to break this bad habit ..

Of course, thinking on it ... the same notes are on both the 1st string, high E and the 6th string .. low E ...

...

Anyhow.. good stuff.. this is why I post. Always find out something new, or info to work on, or add to my knowledge
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