Chords

noq23

New member
Hi.I am a newbie here.How do you derive the C7, E7, G7, D7 and i think other dominant 7th chords?

I try to look up on youtube but can't seem to understand how they derive it.I don't wan to just memorize it.I want to know how C7 was derived by the C major chord.help me please. :)
 
Its a Cmaj triad with an added minor seventh interval above the root(C).
So that would be: C, E, G, Bb (minor seventh interval above C).
There are some movable chord shapes for dominant 7th chords so it wouldn't hurt to invest some time figuring them out !
 
like mrekoj said, the dominant is made up of 1 3 5 and a flat 7. i'll try and explain it out here, see if i can do it...

root 6: G7
E-3 (root note: G)
A-5 (5th note: D)
D-3 (flat 7: F)
G-4 (root note: B)
B-3 (3rd note: D)
e-3 (root note: G)
comparing with the major key, the notes are G A B C D E F#

root 5: C#7
E-X (dont play)
A-4 (root note: C#)
D-6 (5th note: G#)
G-4 (flat 7: B)
B-6 (3rd note: F) ok not sure why this is a flat 3 also, maybe others can explain lol
e-4 (5th note: G#)
comparing with the major key, C# D# E# F# G# A# B# (for this purpose only its called E#)

hope this helped :)
 
root 5: C#7
E-X (dont play)
A-4 (root note: C#)
D-6 (5th note: G#)
G-4 (flat 7: B)
B-6 (3rd note: F) ok not sure why this is a flat 3 also, maybe others can explain lol
e-4 (5th note: G#)
comparing with the major key, C# D# E# F# G# A# B# (for this purpose only its called E#)

hope this helped :)

The F in C#7 is actually the major third, since a M3 up from C# is E# which is the same as F since they are enharmonic.
Alternatively you might want to play the C#7 this way:

x
6
4
x
4 (C#-root)
x

The 5th can be omitted since the tonality of the Dominant 7th chord is emphasized in the minor 7th interval. You can just move around the A string to get the different Dominant 7th chords with the above shape.

Hope this helps too!
 
You have to look at the scale you're playing in.

a seventh up from the root is basically a second down from the same root

there are only 3 types of seventh chords.

major seventh=minor second down (1 semitone)
minor seventh=major second down (2 semitones)
diminished seventh=augmented second down (3 semitones)

A C chord is also known as a C major chord. A Seventh is by default a minor seventh.

so by default

a C7 chord is a major C chord and a minor seventh.

a Cmaj7 would be a major C chord and a major seventh.

a Cmin7 would be a minor C chord with a minor seventh

a Caug7 would be a augmented C chord with a major seventh

a Cdim7 would be a diminished C chord with a diminished seventh

a Chalf-dim7 would be a diminished C chord with a minor seventh

in a C major scale the seventh of the C would ALWAYS be Cmaj7 because the seventh of the C is B which is a major 7th. it is impossible to have any other type of C seventh chord in a C major scale because of the notes in the scale. there is no Bb in a C major scale so you will not be able to get any other type of C seventh chord in it.

you have to draw it out on staff lines to see..
 
Actually he never mentioned that he was in the key of C, but other than that you'd be right to say that there is no Bb in the key of C ! C7 would instead appear in the key of F.

And there's also a fourth type of 7th chord: the minor-seventh-flat-five chord.
 
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