Author Topic: Open 7 Chords  (Read 6384 times)

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Offline cu2morrow

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Open 7 Chords
« on: August 06, 2014, 07:44:09 am »
I Justin, just went through your chord construction theory and there were no questions to it until it tried to construct open 7 chords.

The shape for
minor 7 is 1, b3, 5, b7
major 7 is 1, 3, 5, 7

but if i identify the chords used for a open 7 chord (e.g. G7, C7, ...) i get the following shape: 1, 3, 5, b7

How comes that the shape for open 7 chords seems to be different?

Many thanks,
Marcel

Offline shadowscott007

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Re: Open 7 Chords
« Reply #1 on: August 06, 2014, 09:55:58 am »
There are three basic types of 7th chord.

The last type you listed is called a "dominant 7" it has a major 3rd (3) and a minor 7 (b7).

So minor 7th has a b3 and a b7.  Cm7 minor third minor 7th.

And major 7th has a 3 and a 7.  Cmaj7 major third major 7th

Lastly dominant 7 has a 3 and a b7.  C7 major 3rd minor 7th.

The naming convention can be a bit confusing at first.

Shadow
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Offline TB-AV

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Re: Open 7 Chords
« Reply #2 on: August 06, 2014, 03:27:58 pm »
Just to add, when your chord shows no other name.. Maj, m, then it's Dominant and that wording is left off.

C7
Cm7
CMaj7
C-7
C+7
C[triangle]7

So [Chord Letter}7  is Dominant chord type. Same with C9, C11 It is assumed you will spell it as a Maj chord with a b7.

In this chord, the Maj3rd and b7 form a TriTone.  C D E F G A B  as in E to Bb  E to F# = Tone F# to G# = Tone G# to A#/Bb = Tone ... Three Tones apart.... TriTone.

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Offline cu2morrow

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Re: Open 7 Chords
« Reply #3 on: August 07, 2014, 05:53:44 am »
thank you both - that explains a lot   -  now i can continue my journey on chord construction :)

Offline mouser9169

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Re: Open 7 Chords
« Reply #4 on: August 07, 2014, 01:48:37 pm »
Just to be complete, you also have minor (major 7) chords: Minor 3rd, Major 7th.

Not as common as the main three, but you will run across them. Generally written like A min(maj 7) or A-(maj 7) or A-("triangle" 7).
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Offline shadowscott007

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Re: Open 7 Chords
« Reply #5 on: August 07, 2014, 02:20:47 pm »
Now that the can of worms has been popped, to be even completerer:

(As a beginner you can probably safely ignore these - what I like to call goofy - rarer chords for a while.)

From within the major scale you can also get a "minor 7 flat 5" which is a 1 b3 b5 b7.  It is built off the 7th degree of the major scale. Written as Cm7-5, Cm7b5, and other ways.  This is one of the more common goofy chords you will run across.  Seen this in some of Justin's song lessons.

There is also a "diminished 7th" chord, 1 b3 b5 bb7 (or 1 b3 b5 6 if you prefer) from the harmonic minor scale.  Cdim7. This one pops up a bit to.  In at least one of Justin's song lessons.

The "major minor 7th" "minor major 7th" can be found in both the melodic minor and harmonic minor scale harmonizations.  Don't see this much, but I'm not much of a jazz guy.  If I was gonna go look for it it would be there.  I think there was a lesson where Justin mentioned this chord.

There is one more, a "major 7 augmented" 1 3 #5 7.  Cmaj7#5. Again from harmonic minor.  Never seen that one in the wild.  I think I've run across all the others at least once.

Shadow

Edit: corrected typo
« Last Edit: August 07, 2014, 05:03:38 pm by shadowscott007 »
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Offline mouser9169

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Re: Open 7 Chords
« Reply #6 on: August 07, 2014, 04:27:24 pm »
So what's the difference between a major (minor 7th) and a dom 7? The min(maj 7) is the "missing" combination of maj/min 3rd and maj/min 7th:

maj 3/maj 7 = major 7th
maj 3/min 7 = dominant 7th
min 3/min 7 = minor 7th
min 3/maj 7 = min(maj 7)

As for the others you listed, the first (min7b5) is also called a half-diminished: written as a circle with a slash through it. I'd call it a toss up (because I can't really remember enough of either) between that and the dim 7 for more common.
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Offline shadowscott007

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Re: Open 7 Chords
« Reply #7 on: August 07, 2014, 04:46:22 pm »
Well to answer your question there is no difference nothing.  I just typed the major and minor backwards in my sentence, was just trying to indicated the source scale of the chord you had added.  Need to go back and correct that...

Shadow
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Offline TB-AV

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Re: Open 7 Chords
« Reply #8 on: August 07, 2014, 05:15:08 pm »
The is no need to concern yourself with the "source scale" other than to stick with the Major Scale.

You have 4 triad types.. meaning formed from 3rd intervals

Major --- 1 3 5  = M3 + m3 = C E G
Minor --- 1 b3 5 = m3 + M3 = C Eb G
Augmented --- 1 3 #5 = M3 + M3 = C E G#
Diminished --- 1 b3 b5 = m3 + m3 = C Eb Gb

All that from the Major Scale... after that you add your desired 7th degree..... bb7 b7 7

Half Diminished means the m3rd connection is broken C Eb Gb Bb .. Gb to Bb = M3
Diminished means all m3rd = C Eb Gb Bbb = m3 + m3 + m3 .. this is not 1 b3 b5 6 even though the note is en harmonically equivalent. .. Bbb=A in frequency of tone for our instruments.

There is no need to learn all the minor scales to learn and accomplish the task of learning to name and build chords. Chords are named out of the Major Scale.

OP,,, if you don;t have it, get a copy of Justin's PMT ( Practical Music Theory ) money well spent.

You need to learn how to form your base triad to name your chord, then tack the other stuff on the end.

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Offline shadowscott007

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Re: Open 7 Chords
« Reply #9 on: August 07, 2014, 05:34:02 pm »
TB, agree.  To name the chords all you need is the major scale.  I was anticipating an unasked question...

Shadow
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Offline TB-AV

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Re: Open 7 Chords
« Reply #10 on: August 07, 2014, 06:20:22 pm »
I was anticipating an unasked question...

In that case my answer would be that these 'other notes' are accidentals. Again we are talking about naming and building chords and not composing.
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