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dustandbarley

Chords, and the scales they relate to - C7(b5)...??

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Hello folks

Briefly, would you consider C7(b5) as an alternative/lazy way of writing C7(#11)? 

To me C7(b5) suggests a scale of C,D,E,F,Gb,A,Bb,C...  yuk!

What am I missing?

Thanks :) 

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In terms of chord/scale relationships, C7#11 would usually imply a Lydian dominant scale: C D E F# G A Bb (has the #4 and perfect 5 above the root)

I believe C7b5 implies a whole-tone scale: C D E F#/Gb Ab Ab (only the b5 above the root, no perfect 5). I guess it could also imply a super locrian/ altered scale (C Db Eb E(Fb) Gb Ab Bb) although you'd usually denote altered chords using C7#9 or CAlt.

 Is this any help?

@Joebass is good at explaining this stuff!

Edited by Ceebass

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Hi Ceebass, thanks for your reply.  I agree with what you say about how a super locrian/altered scale is normally written - 

16 minutes ago, Ceebass said:

although you'd usually denote altered chords using C7#9 or CAlt.

I'm confused about thinking of C7(b5) as a whole tone scale as the whole tone scale has a #5, and I'd be looking for C7+ (maybe C7(#5) or C7(#4,#5) )

Happy to take this onboard though - thanks

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Yeah, you're right about the whole-tone thing. I was trying to think of examples of scales where the naturally occurring 5th degree is flattened...

I might have to go and do some reading!

 

 

Edited by Ceebass

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6 minutes ago, Ceebass said:

 I was trying to think of examples of scales where the naturally occurring 5th degree is flattened...

Me too :) 

To elaborate on why I'm asking, I was chatting about chords with my keys player and he referred me to a source https://www.apassion4jazz.net/jazz_chords.html -  I like to dig out the Free Jamey Aebersold Red Jazz book http://jazzbooks.com/jazz/FQBK when I need to freshen up on chords and scales - page 14 has a scale syllabus I use for deciphering chords and scales. However,  I liked the look of my keys players' chart and thought I'd do one of my own to include whole scales, not just chord tones, so I started my own chart using his as a template.  The grey filled cells show chord tones and I intend to fill in the notes.  I've only done 2 lines in the example before noticing the fifth line and the chord C7(b5) hence the post.

Screen Shot 2018-02-09 at 13.24.53.png

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I like this! I guess the problem is the chord symbol doesn't definitively imply (?) one particular scale (I think I'm just saying what you said, again :biggrin:). 

I found this on jazz-guitar-licks.com (best/worst domain name ever):

"Dominant 7b5 chords imply only 4 notes, unlike 7#11 chords (which) are made up of 6 notes... the ninth and the perfect fifth will be omitted"

It seems that it's generally thought the correct chord/scale relationship is 7b5=altered, but the chord is sometimes (wrongly?) used interchangeably with 7#11 and 7+. So... back to the start?

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One possibility for C7(b5) is the halftone-wholtone scale. Afaik in englisch/american terminology also known as "c diminished scale" 

C- Db - Eb-  Fb  (=E) -  Gb - G - A- Bb - C

The scale constists of 8 tones, not 7 as usual. 

A common scale for C7(#11) is c lydian scale, the 4th mode of the g major scale. 

C - D - E - F#  G - A - B.

Not?

Edited by GerdO

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1 hour ago, GerdO said:

One possibility for C7(b5) is the halftone-wholtone scale. Afaik in englisch/american terminology also known as "c diminished scale" 
Not?

Maybe Gerd0?  For the half-tone / whole-tone diminished scale, I'd be looking for C7b9 as the chord symbol.  Like with the altered scale mentioned by Ceebass, I think I'd be looking for a different chord symbol than C7(b5)...  Maybe as Ceebass suggested the "scale" for C7(b5) is only made up of the 4 chord tones???  

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15 minutes ago, dustandbarley said:

Maybe Gerd0?  For the half-tone / whole-tone diminished scale, I'd be looking for C7b9 as the chord symbol.  Like with the altered scale mentioned by Ceebass, I think I'd be looking for a different chord symbol than C7(b5)...  Maybe as Ceebass suggested the "scale" for C7(b5) is only made up of the 4 chord tones???  

For me this: 

2 hours ago, Ceebass said:

"Dominant 7b5 chords imply only 4 notes"

says only that the chord symbol C7(b5) defines 4 notes, wich is nothing unusual. All 4 tone chords define 4 tones. All 6 tone chords (like C7(#11) define 6 tones.


Wich scale to play when the chord  is played depends strongly on the tonal context.  But in many cases the WT/HT scale can be played  when a C7(b5) is sounding. 

Assume the sheet shows a G7 chord and the tune is written completley in c-major. The  first scale choice will be c-mixolydian, because that is the 5th mode of the g-major scale and the G7 is the 5th chord of the g major scale. 

Now assume the tune is written completley in c-minor.  Then the first choice to play over G7 would be the phrygian-dominant scale, wich is the 5th mode of the  harmonic minor scale . 

Chords don't imply scales. The choice of the appropriate scale  to play depends on the chord sounding and the actual tonal context ( and: taste, not to forget).  

 

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1 hour ago, GerdO said:

says only that the chord symbol C7(b5) defines 4 notes, wich is nothing unusual. All 4 tone chords define 4 tones. All 6 tone chords (like C7(#11) define 6 tones.

I think, possibly, I should have put more of the quote in: it tries to explain why you would need to use a 7b5 chord symbol, rather than 7#11/b9/#9 etc. (all of which could contain 1/3/b5/7). If you specifically wanted the voicing to contain C E Gb Bb with no upper extensions or alterations, C7b5  would be one way of writing it. 

I would argue that chords do imply scales, particularly those with multiple extensions. Surely this is one of the main principles of chord/scale theory? @GerdO you are right that tonal context & taste are also equally, but if you play a C7b13#9 chord, a C altered tonality is implied, as this is the scale from which those notes are drawn. 

It's nice to do a but of thinking on a Sunday (in between looking after my kids!) Thanks dudes 👍

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One chord alone, in isolation, cannot define which scale underlies it. However it would eliminate many possibilities, leaving 3 or 4 reasonable possibilities, and out of these there are more popular/likely choices. C7b5 doesn't fit into any diatonic scale, nor the harmonic or melodic minor, so if you really want to "pin" a scale to it, then you're into wholetone or octatonic stuff, or other weird stuff.

It would be better to evaluate the chord progression over a number of bars rather than just that one chord in isolation - do you have the other chords? It may well be that the C7b5 is a passing chord which uses notes outside of the underlying scale, and that the scale is much less 'exotic'.

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On 2/11/2018 at 09:22, dustandbarley said:

 

I'm confused about thinking of C7(b5) as a whole tone scale as the whole tone scale has a #5, and I'd be looking for C7+ (maybe C7(#5) or C7(#4,#5) )

 

The wholetone scale has 6 notes, so fitting a "naming system" consisting of 7 notes is always going to be a struggle. I'd take the labels such as b5 and #5 with a pinch of salt. 

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16 minutes ago, paul_c2 said:

It would be better to evaluate the chord progression over a number of bars rather than just that one chord in isolation - do you have the other chords? It may well be that the C7b5 is a passing chord which uses notes outside of the underlying scale, and that the scale is much less 'exotic'.

Hi Paul, thanks for your additional explanation, unfortunately in this instance the question arose about C7(b5) when looking at the chord in isolation - for a quick reference chart. See post above https://www.basschat.co.uk/topic/319913-chords-and-the-scales-they-relate-to-c7b5/?do=findComment&comment=3464919

and yes, happy to take it with a pinch of salt.  

Edited by dustandbarley

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5 minutes ago, dustandbarley said:

the question arose about C7(b5) when looking at the chord in isolation

I know you're looking at the chord in isolation, and the above applies all the more, let me paraphrase it:

1. If you're looking at one chord in isolation, there is not a 1:1 relationship to the scales which can apply to that chord - many scales (pragmatically, about 3 or 4 non-weird ones) could equally apply. If you nominate one scale over the others, its simply a "best fit" and doesn't render the other choices wrong.

2. If you're looking at a chord and are able to provide more context, eg by considering the musical situation it applies in, then the context gives much more information and could suggest a (as in, one, not 3 or 4) scale.

 

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Thanks Paul, I'm happy to take on board your points, and without the chord being placed in a musical context, more than one option is / could be suitable.  With this in mind I realise the purpose of a quick reference table is a little flawed without listing all possible scale choices, but as its just for me, I'm happy to just list the chord tones and take on board that I have to look at the musical context when the chord is being used in order to make choices about the notes I'm going to play..  (I suppose in practise this doesn't really happen as my ear is largely dictating what I play next, but something to think about nevertheless). :) 

Edited by dustandbarley

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Also its worth mentioning that the C7b5 chord is a VERY unusual chord! On first appearance, it seems to have a major 3rd and a b5, thus, the 4th of a (7 note) scale must be the pitch in between (if we're sticking with 12TET, of course) thus there's 3 notes in the accompanying scale all next to each other, a semitone apart. There's a couple of different ways to resolve this 'anomoly' - either fit it to a scale without worrying if the notes of the chord form the root, 3rd, 5th and 7th of that scale (ie depart from the idea that chords are built on 3rds). Or, even though its not written, imply that the 3rd is in fact a minor 3rd, not a major 3rd, and interpret C7b5 as a (fairly normal) half-diminished 7th chord.

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Sorry guys , I m New at theory etc .... I know scales /chords

but how do you determine which scale goes with which chord ? 

For instance ....

if in key of F major  would you play the scale modes over each chord interval? Help me and this might not make any sense to a lot of you

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1 hour ago, fiatcoupe432 said:

Sorry guys , I m New at theory etc .... I know scales /chords

but how do you determine which scale goes with which chord ? 

For instance ....

if in key of F major  would you play the scale modes over each chord interval? Help me and this might not make any sense to a lot of you

There's lots of ways to "enhance" it but basically, the scale would have the notes of the chord in it. This, of course, leads to >1 scale possibility. If its a triad (3 notes) there could be a lot of choices; if its a 7th chord then it narrows it down a bit. Once you have a choice of the scales, there's ones which are more common than others. 

For example, for chord of F (major), you could have:
 

 F Major (ionian)
F mixolydian
F lydian
(and others, weirder stuff)

I've listed them in order of most common - so you'd choose F Major, but there would be nothing wrong with the choice of F mixolydian either, given just one F chord.

 

Edited by paul_c2

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38 minutes ago, paul_c2 said:

There's lots of ways to "enhance" it but basically, the scale would have the notes of the chord in it. This, of course, leads to >1 scale possibility. If its a triad (3 notes) there could be a lot of choices; if its a 7th chord then it narrows it down a bit. Once you have a choice of the scales, there's ones which are more common than others. 

For example, for chord of F (major), you could have:
 

 F Major (ionian)
F mixolydian
F lydian
(and others, weirder stuff)

I've listed them in order of most common - so you'd choose F Major, but there would be nothing wrong with the choice of F mixolydian either, given just one F chord.

 

So is this scenario only if i would be playing those  in key if F Major ? 

What about other fmajor in the key of C ?

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1 hour ago, fiatcoupe432 said:

So is this scenario only if i would be playing those  in key if F Major ? 

What about other fmajor in the key of C ?

If you are in the key of C, then you know the scale....its C

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A better approach is to look at a chord progression rather than each chord in isolation - hopefully at least 3 chords. If the music genuinely only uses 1 or 2 chords for that section, then there will (by definition) be more choices of scales which "fit" (note, I've not said 'right' or 'wrong' - there is no right or wrong as such, although some will sound much more pleasant than others!!!)

If the music has more than 3 chords, (and even if it has less....) there's always a chance of the chords not being diatonic, thus there's some kind of modulation, or use of harmonic minor, or other explanation for the non-diatonic chord (like the use of a Neapolitan 6, or an Augmented 6th chord, or other interesting stuff - or 'just' a modulation). So its not really possible to say with any certainty "3 chords means you can fit a scale to them, 4 chords means you can't" - it really depends on the chords in question and the musical context.

But the basics are well-defined - the chord(s) have the notes of the scale in them, which 'fits'.

If you look at (a lot of) music, you'll see the same progressions pop up again and again - for example a I IV V, or a ii V I, or a I vi VI V or a variation thereof. So after a while you'll see possibly 2 of these chords and know what scale is most likely to fit, and also what other chords might follow or precede the ones you looked at. I'd say you need to have a reasonable understanding of popular chord progressions, to be able to make sense of it all.

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