Beginner theory Dominant 7th chords

[cappers]

I am trying to get my head around chords!

I think I understand Major 7th construction: major chord arpeggio 1,3,5 + 7, whereas the Dominant 7th has a flattened 7th so 1,3,5 + 7b.

CMaj7: C E G B ->** EDom7: CDom7 or more correctly C7: C E G Bb (Thanks @PiccoloPirate)
DMaj7: D F# A C# -> DDom7: D F# A C
EMaj7: E G# B D# -> EDom7 E G# B D
etc

My question is why is it named 'dominant'? I believe the 7th is a 'leading tone', so is the 'dominance' the fact that it needs to resolve down to sound correct? Also can it resolve up instead?

Thank you.

** edited to correct typo

 

[Colin the Bear]

I bet the banjo player loves you.

 

[cappers]

@Dibbs

Apologies for my slowness but would you explain this more.

"the dominant seventh is the seventh chord formed on the 5th (dominant) of the scale".

What I think it means is:

For C Maj the 5th (dominant) note of the scale is G.
The 7th chord of G Maj is G B D F# (Mixolydian mode?) and the Dom7th (G7) is G B D F.

"It's also good to point out that it contains all the scale notes NOT in the tonic triad".

The tonic triad of C Maj is C E G so with the notes of G7 we get G B C D E F, so as @Nick Wyver wrote, where's the A?

For my old brain, thinking M7 is Maj7 with the 7th dropped a semitone is easier to grasp.

 

[BigMartin]

Absolutely. It's far too often taught that the dominant seventh has the seventh note flattened. It should be taught that the dominant seventh is the seventh chord formed on the 5th (dominant) of the scale. It's also good to point out that it contains all the scale notes NOT in the tonic triad.

That's how I learned it first. It’s really good to be aware of both viewpoints, though. For instance, in a ("major") blues the tonic chord has the quality of a dominant (as do the IV and V chords), ie it has a flat 7. It's really a different kind of tonality.

 

[BigMartin]

It takes a while when starting out to realise that terms in music have nothing to do with anything else you know. Your maths brain is affronted by a fourth plus a third being a sixth.

Yes, that's what happens when you decide to call a two-step interval a "third" and so on. I know we're stuck with it now, but it's been annoying me for 50+ years that intervals are counted from 1, rather than zero. If we counted the number of scale steps to get from one note to the other it would make much more sense. Eg, 3 steps plus 2 steps is 5 steps, instead of a 4th plus a 3rd is a 6th

 

[Dr G]

Yes, that's what happens when you decide to call a two-step interval a "third" and so on. I know we're stuck with it now, but it's been annoying me for 50+ years that intervals are counted from 1, rather than zero. If we counted the number of scale steps to get from one note to the other it would make much more sense. Eg, 3 steps plus 2 steps is 5 steps, instead of a 4th plus a 3rd is a 6th

Hmmm, is that baby steps or big steps? What is a half step? Your foot either touches the ground or it doesn’t. If you pick up your foot and move it forward, it is a step. Yikes, next they’ll be calling things semi-steps or some other nonsense. Whatever happened to the universal acceptance of SI units?

 

[Pete Thomas]

I think it means is:

For C Maj the 5th (dominant) note of the scale is G.
The 7th chord of G Maj is G B D F# (Mixolydian mode?) and the Dom7th (G7) is G B D F.

Forget mixolydian mode that just confuses things.

As there is no F# in C the G chord in the key of C is G B D F

 

[Pete Effamy]

the dominant seventh is the seventh chord formed on the 5th (dominant) of the scale".

Getting into a muddle here. Be very careful with words in describing music.

THE seventh chord in any key is a chord built upon the 7th degree of the scale: chord vii. In C major this has the notes BDF(A) - the A can be added for 4 note harmony.

Note use of Roman numerals as the number 7 is confusing.

The 7th chord in a key and a 7th chord are different things. Musicians frequently use “7th chord” as shorthand speak - usually when considered that both parties know the harmony - “let’s go from the 7th chord” type thing. It could also mean any chord with a 7th degree in it - m7 for example.

Back to your words -

Remove the word “seventh “ preceding the word “chord”.

The dominant 7th chord is a chord built a upon the 5th note of a key (the so-called dominant) and has the 7th degree of this chord added to the triad 1,3,5.

 

[Colin the Bear]

@Dibbs

Apologies for my slowness but would you explain this more.

"the dominant seventh is the seventh chord formed on the 5th (dominant) of the scale".

What I think it means is:

For C Maj the 5th (dominant) note of the scale is G.
The 7th chord of G Maj is G B D F# (Mixolydian mode?) and the Dom7th (G7) is G B D F.

"It's also good to point out that it contains all the scale notes NOT in the tonic triad".

The tonic triad of C Maj is C E G so with the notes of G7 we get G B C D E F, so as @Nick Wyver wrote, where's the A?

For my old brain, thinking M7 is Maj7 with the 7th dropped a semitone is easier to grasp.

A major 7 is just that and contains the 7th note of the scale.

A dominant 7 has the flattened 7th note of the scale.

All melodies can be harmonised simply using I IV V7 vi. Any pop song for instance.
Upper case for major chords. Lower case for minor chords

These four chords contain all the notes of the major scale.

In key of C major, your missing A is in the IV, F A C and the vi A C E.

C, F, G7, Am.

GBDF# is Gmaj7 and not in the key of C Major. Whereas G7, G B D F is.

 

[Pete Effamy]

A dominant 7 has the flattened 7th note of the scale

I know what you mean but this is confusing as a definition.

- which scale?

 

[Colin the Bear]

To train your ear and fingers try playing this exercise.

CEGB C maj7
DFAC. Dm7
EGBD Em7
FACE. Fmaj7
GBDF G7
ACEG Am7
BDFA Bm7b5 sometimes called half diminished

 

[Colin the Bear]

I know what you mean but this is confusing as a definition.

- which scale?

I'm just answering a question and keeping it at a level the questioner Will understand.

Too much too soon can be overwhelming. 👍

 

[cappers]

.........

The dominant 7th chord is a chord built a upon the 5th note of a key (the so-called dominant) and has the 7th degree of this chord added to the triad 1,3,5.

@Pete Effamy and others, I am sorry but I just want to check I have the above correct now.

In the key of Cmaj the 5th note (dominant) is G. The G triad in the key of C is GBD 1,3,5.
The 7th in the key of G is F# but F in the key of C. Thus GBDF = G7.

 

[wakyct]

Maybe it's just me but I've never heard the 5th degree of a scale called the 'dominant note'. There is a dominant chord, the V, when you harmonize (i.e. build chords) a scale starting from a key note.

Where do they call the 5 a dominant note?

I know what you mean but this is confusing as a definition.

- which scale?

I think it makes more sense re-worded slightly as "a dominant 7 has a flattened 7th note, which is in the scale of the key". Would that be right in all cases?

 

[cappers]

To train your ear and fingers try playing this exercise.

CEGB C maj7
DFAC. Dm7
EGBD Em7
FACE. Fmaj7
GBDF G7
ACEG Am7
BDFA Bm7b5 sometimes called half diminished

Thank you @Colin the Bear
I do this after doing the scales around the cycle of 5ths (still get a bit stuck on B F# C# Ab for some reason). Then the arpeggios and slowly my ears are learning.

I understand the talk about the dominant seventh is the seventh chord formed on the 5th (dominant) of the scale etc but unless I'm doing something wrong is it ok just to think the M7 is just the Maj7 with the 7th down a semitone?

Anyway it's theory and at my stage I think I just need to blow and listen more and think less!

 

[Pete Effamy]

@Pete Effamy and others, I am sorry but I just want to check I have the above correct now.

In the key of Cmaj the 5th note (dominant) is G. The G triad in the key of C is GBD 1,3,5.
The 7th in the key of G is F# but F in the key of C. Thus GBDF = G7.

Yes, don’t forget that the dominant is the 5th of a key - a chord built upon the 5th of a key . Therefore the reference to this chord being a key chord, a 1 chord, is irrelevant.

Ie

Key of C major: dominant 7th is GBDF - all notes contained in key of C major.

Key of G major: chord 1 is GBD and for an added note the major 7th (7th degree is a major 7th by definition): GBDF#

 

[Pete Effamy]

the seventh chord

It’s not the seventh chord.

It’s:

- a 7th chord
- a dominant (7th) chord

THE seventh chord is a chord built upon the seventh degree of a scale

 

[Pete Thomas]

In the key of Cmaj the 5th note (dominant) is G. The G triad in the key of C is GBD 1,3,5.
The 7th in the key of G is F#

As the chord is in the key of C there is no need to even think about the key of G, hence F# is irrelevant.

but unless I'm doing something wrong is it ok just to think the M7 is just the Maj7 with the 7th down a semitone?

No. it’s confusing to use capital M as in M7. With chord symbols think of Cmaj7 or G7 (dominant in C7

People do sometimes use M to mean major or m to mean minor. But the M is confusing as it can look like m when written by hand so it’s best to use maj or min. For minor m is normal as in Dm7 and but M for major is just confusional. So best avoided.

 

[PiccoloPirate]

Try playing this,
CDEFGABC start on C1
DEFGABCD
EFGABCDE
FGABCDEF
GABCDEFG
ABCDEFGA
BCDEFGAB
CDEFGABC start on C2

You should also try going up and down.
A metronome is helpful.
Slowly.

Somewhere on this site is an arpeggio exercise for those scales.
Try not to let knowing why, cause confusion.
Playing is what's most important.
Best advice based on your posts.
Ya don't need theory, to be melodic.

 

[BigMartin]

Hmmm, is that baby steps or big steps? What is a half step? Your foot either touches the ground or it doesn’t. If you pick up your foot and move it forward, it is a step. Yikes, next they’ll be calling things semi-steps or some other nonsense. Whatever happened to the universal acceptance of SI units?

Well if it comes to that, is it a big third or a baby third? I'm talking about exactly the same sytem of nomenclature but with the numbers reduced by one and preferably expressed in cardinal rather than ordinal form. But yes, it's too late now and we have to stick with what we've got. The SI sytem of units was better thought out, though.

 

[BigMartin]

It’s not the seventh chord.

It’s:

- a 7th chord
- a dominant (7th) chord

THE seventh chord is a chord built upon the seventh degree of a scale

To be picky, I'd call a chord built on the 7th a vii chord (with no "th").