#1
ive been studying chord theory i understand everything fine but im a little stumped in dominant 7ths this is what i know...

if you add the flat 7th to the major triad you get the
so-called dominant 7th chord

can someone explain this to me more clearly thanks
#2
to form a dominant 7th you take a major triad and add the fourth note by adding the major 3rd (up three semi-tones) above the 5th (from the triad)

edit: get it?
Last edited by heaven's gate at Aug 16, 2006,
#3
dominant sevenths are really easy to understand if you have a piano or a keyboard or know how to play piano of some sort. i've taken piano lessons for 10 years, so i just pick out dominant sevenths by ear now, so i can't really explain it. but you go up 5 notes from your root note of the scale you're on to the fifth, (which is why it's called DOMINANT sevenths, the fifth note of the scale is called dominant) and then you pick out a major triad, and add a major third to the end, or the seventh note of the root scale. understand?
ferret.
#6
basically what you first said. add a flat 7 to a major triad

so you have 1-3-5-b7 as your chord formula. so you have root, major third, perfect fifth, and flat seventh.

if you were play a C7 (c dominant 7) the notes would be c-e-g-Bb.

so in the major scale (I ii iii IV V vi viidim), dominant 7 only occurs on the fifth note/chord of the scale.
#7
umm.. yeah. so in a c major dominant seventh, you'd play g on the bottom, then b, then d, then f. and in a g major dominant seventh, you'd play d, f sharp, a, c. get it?
ferret.
#8
Quote by Don't Read This
so the spelling (formula not sure) is

root
major third
perfect fifth
and major third again?


no. firstly because you're mixing some ideas there, and also the guy was wrong in the first place. it's not a major third above the fifth, it's a minor third above the fifth. he did say three semitones which is a minor third, but likely accidentally wrote major.

now the way you just wrote it is confusing because for the first three notes (root third and fifth) you wrote the distance from the root. for the fourth not, you wrote the distance from the fifth.

a dominant seventh chord is a root, a major third, a perfect fifth, and a minor seventh (flat seventh). so a C7 is:

C E G Bb

if you want the spacing between the notes, it looks like this:

C <major third> E <minor third> G <minor third> Bb
"I see my light come shining from the west down to the east
Any day now, any day now I shall be released"

Know any good teachers in NY, especially skilled in teaching ear training? Tell me
#9
Quote by mikr_guitar
umm.. yeah. so in a c major dominant seventh, you'd play g on the bottom, then b, then d, then f.



thats a g dominant 7, not a C dominant 7.
#10
sort of ok the formula is 1 3 5 b7

the notes in a F7 are F A C D#/Eb
the notes in a D7 would be D F#/Gb A C

sorry if im not getting this its just confusing for some reason
#11
Quote by Don't Read This
sort of ok the formula is 1 3 5 b7

the notes in a F7 are F A C D#/Eb
the notes in a D7 would be D F#/Gb A C

sorry if im not getting this its just confusing for some reason


Yes, that right, let me just explain. In a chord progression the V chord is called the dominant chord. In the key of C the V chord is a G Major:


1 2 3 4 5 6 7
C D E F G A B 


Now the only dominant 7th chord here is the G7 because the dominant 7 chord is built off the dominant chord of the scale, namely the V chord; to build this G7 we use the 1,3,5 and b7 of the G Major Scale:

G,B,D and F

Notice how all these notes also appear in the C Major scale. Let's look at adding a b7 to the other Major chords in the key of C:

F Major:

F A C Eb

That was good until the Eb, the Eb doesn't appear in the C Major scale

C Major:

C E G Bb

The Bb doesn't appear in the C Major Scale either, so the only dominant 7 chord that can be created using the notes in the C Major Scale is the G7 chord.

Try not to get confused however as a b7 can still be added to other chords in a progression but they are not functioning as a dominant 7th withinin the progression itself.

Hope that's helped you a little.

#12
Quote by Don't Read This
sort of ok the formula is 1 3 5 b7

the notes in a F7 are F A C D#/Eb
the notes in a D7 would be D F#/Gb A C

sorry if im not getting this its just confusing for some reason


yep, except that in F7 the D# would be an augmented sixth. even though it's enharmonic to Eb, the seventh of F7 is Eb. same goes for D7...the third is F#.
"I see my light come shining from the west down to the east
Any day now, any day now I shall be released"

Know any good teachers in NY, especially skilled in teaching ear training? Tell me
#13
Well, dominant chords are actually not built from the major scale but rather from a mode of the major scale known as the dominant scale. This is coincidentally the same as the major scale with a flattened seventh. So basically, if you formed a major triad from this scale, it would be identical to that from the major scale. Only by adding the seventh of the scale do you form a 7th. If you did this using the major scale, you would end up with a Xmaj7 chord. From the dominant scale, you would end up with a X7 or Xdom7 chord. For example, in the key of C:
C D E F G A B C = major scale Major 7th
C D E F G A Bb C = dominant scale Dominant 7th

If you took the 1 3 5 from each scale, you would have the same major chord. Only by adding the 7th will you notice any difference. Looking at dominant chords as a different "family" per se, than major or minor chords will help you to understand I hope. Cheers
#15
think of it this way. a major 7th has a note a half step flat of an octave, and thus will sound more like a minor chord(sadder) the minor 7th (also known as jus the seventh) has a note a whole step down from an octave, and thus will sound happier