Dominant 7th Chords

[Mushroo]

Does the term "7th chord" imply a "dominant 7th chord"?
Are all "dominant 7th chords" built on the 5th scale degree?
Must "dominant 7th chords" resolve?

Discuss.

[MarkTAW]

Yes, but I'm not 100% up on my jazz theory, so I'm going to say "usually."

Yes, that's what Dominant means. The dominant is the 5th, just as the subdominant is the fourth, the mediant is the third and so on.

No, of course not, nothing in music MUST do anything. Just ask Wagner or Schoenberg how long you can go without resolving something.

Part of what gives the dominant 7th its power is the leading tone on 3 and the tritone relationship between the leading tone & the 7th. In C major, the dominant 7th is spelled G, B, D, F. The B is the leading tone of C, it forms a tritone with the F, which resolves to E.

[mambo4]

Originally Posted by Mushroo

Does the term "7th chord" imply a "dominant 7th chord"?

Yes, unless preceded by other modifiers like "Major" "Minor" "diminished" or "Augmented". "7th" by itself always means "dominant 7th"

Are all "dominant 7th chords" built on the 5th scale degree?

No, 7th chords can show up on all scale degrees (and even non-scale degrees) depending on the music. They are not always the 5th of the key you're in. For examples, in basic blues, every chord, I-IV-V, is a 7th.

Dominant chords, having 4 notes and a mix of intervals, match or closely match a variety of other chords that make it harmonically flexible, so it shows up in a variety of places relative to the key center.

Must "dominant 7th chords" resolve?

Again, no. You can follow a dominant chord with whatever your ear pleases, some will sound better than others. But generally resolving down a fifth will sound the most tension-releasing.

Dominant chords are thought of as "unstable" chords. They really want to move, especially down a fifth. One way its been described: The flat 7 interval implies motion, where the major 7 interval implies stability.

[Mushroo]

Ah Mark, welcome to our new thread!

(this is continued from here, BTW: Bm-C#7 to Bm7? Questions.)

If I was writing a book on music theory, my chapter on "7th chords" would include all chords based on natural, sharp, or flat variations on 1-3-5-7 (CMaj7, C7, Cmin7, Cmin7b5, etc.) under the umbrella term "7th chords."

And yet, if you said "play C7," I would automatically play C-E-G-Bb.

Here is another question for the group: Do "C7" and "C7th" mean the same thing to you? Hmm. In other words, is there a difference between saying "seven chord" and "seventh chord?"

[onlyclave]

Originally Posted by Mushroo

Does the term "7th chord" imply a "dominant 7th chord"?
Are all "dominant 7th chords" built on the 5th scale degree?
Must "dominant 7th chords" resolve?

Discuss.

"Dominant" refers to it's function.
"X7" implies a dominant 7 chord, otherwise the quality of the 7th or the triad would be specified eg C7 (C E G Bb) Cm7 (C Eb G Bb) Cmaj7 (C E G B)
Not all dominant function chords are built on the 5th scale degree. In major tonalities the leading tone viio is a dominant function chord.
In C major an F# in the melody would most likely indicate a D major chord (see The Star Spangled Banner) which is a Secondary Dominant. It is analyzed as V/V and would resolve to the chord on the bottom (V or in the case of C major G).
All dominant chords resolve somewhere. V-I is a perfect authentic cadence, V-vi is a deceptive cadence. Chord X > V7 (end of phrase) > Chord Y would be a half cadence.

[MarkTAW]

Originally Posted by mambo4

No, 7th chords can show up on all scale degrees (and even non-scale degrees) depending on the music. They are not always the 5th of the key you're in. For examples, in basic blues, every chord, I-IV-V, is a 7th.

Dominant chords, having 4 notes and a mix of intervals, match or closely match a variety of other chords that make it harmonically flexible, so it shows up in a variety of places relative to the key center.

I respectfully disagree. (edit: in this context the question & answer appear separate, I was answering the question "Are all "dominant 7th chords" built on the 5th scale degree? No.")

a) Dominant means the fifth scale degree. The word Dominant means V.

However if you meant "can other sorts of 7th chords - major, minor, etc. show up in other places" then the answer is yes. But a Dominant 7 chord is a V7 by definition.

b) The tritone flat 5 only occurs on the 7th scale degree, to which you add a 3rd below it to make a V chord.

c) Even in the minor scale where this is technically moved, great care is used to not create a tritone in the wrong place & to restore the tritone relationship to the V chord - witness the harmonic & melodic minors.

[Mushroo]

What are some scales we can play over a C7 chord? I will get the ball rolling: C Mixolydian.

[onlyclave]

Originally Posted by MarkTAW

I respectfully disagree.

a) Dominant means the fifth scale degree. The word Dominant means V.

However if you meant "can other sorts of 7th chords - major, minor, etc. show up in other places" then the answer is yes. But a Dominant 7 chord is a V7 by definition.

b) The tritone flat 5 only occurs on the 7th scale degree, to which you add a 3rd below it to make a V chord.

c) Even in the minor scale where this is technically moved, great care is used to not create a tritone in the wrong place & to restore the tritone relationship to the V chord - witness the harmonic & melodic minors.

"Dominant" refers to harmonic function.

Yes I know:
I = tonic
ii = supertonic
iii = mediant
IV = subdominant
V = dominant
vi = submediant
vii = leading tone

a "Dominant" chord by name means the fifth scale degree but functional harmony is all about Function.

V and vii chords are dominant function chords. They are closely related but they are two different chords both with dominant function.

[onlyclave]

Originally Posted by Mushroo

What are some scales we can play over a C7 chord? I will get the ball rolling: C Mixolydian.

The answer is chromatic. You can play anything you want on this chord and it becomes an alteration.

See: C alt.

[Mushroo]

Originally Posted by MarkTAW

Dominant means the fifth scale degree. The word Dominant means V.

However if you meant "can other sorts of 7th chords - major, minor, etc. show up in other places" then the answer is yes. But a Dominant 7 chord is a V7 by definition.

Ah yes, "Dominant" means "5th degree of the scale" but check it out: "Major" can mean "a scale spelled 1-2-3-4-5-6-7-8" but it can also mean "a chord spelled 1-3-5." Is it possible the word "dominant" has different meanings in different contexts, i.e. it can mean either "the 5th scale degree" or "any chord spelled 1-3-5-b7, regardless of which scale degree it is built upon?"

Historically, they probably called it a "Dominant 7th chord" because, at that time, they only existed on the 5th scale degree. Later, composers figured out how to build this type of chord on other scale degrees, but the name "dominant 7th" stuck out of habit. That's my theory anyway

[MarkTAW]

Originally Posted by Mushroo

Here is another question for the group: Do "C7" and "C7th" mean the same thing to you? Hmm. In other words, is there a difference between saying "seven chord" and "seventh chord?"

Aloud, a "seven chord" would be a chord built on the 7th note in the scale, a viio (lowercase for minor, o for diminished).

In writing, C7th and C7 are basically the same.

We use roman numerals to mean chords when writing & numbers to mean what type to avoid confusion. V7 = "a five seven chord."

[MarkTAW]

Originally Posted by onlyclave

"Dominant" refers to it's function.
"X7" implies a dominant 7 chord, otherwise the quality of the 7th or the triad would be specified eg C7 (C E G Bb) Cm7 (C Eb G Bb) Cmaj7 (C E G B)
Not all dominant function chords are built on the 5th scale degree. In major tonalities the leading tone viio is a dominant function chord.
In C major an F# in the melody would most likely indicate a D major chord (see The Star Spangled Banner) which is a Secondary Dominant. It is analyzed as V/V and would resolve to the chord on the bottom (V or in the case of C major G).
All dominant chords resolve somewhere. V-I is a perfect authentic cadence, V-vi is a deceptive cadence. Chord X > V7 (end of phrase) > Chord Y would be a half cadence.

Generally people don't build chords from the vii because the lack of a perfect 5th makes it too unstable. The tones in the chord don't emanate from the root / overtone series. Adding the 5th beneath it making it a V7 chord ensures that all the notes have their proper grounding.

[Mushroo]

When y'all listen to the blues, and they play I7, do you guys hear that as wanting to resolve to IV (in other words, V7/IV)? What about IV7, does that want to go to bVII (V/bVII)? Or is there something unique about the blues that suspends functional harmony? Now what about the V7 in the turnaround? That really is a dominant 7; when I am playing the blues, is there something special I can do to signal "this time I really mean it!"

[Mushroo]

Originally Posted by onlyclave

The answer is chromatic. You can play anything you want on this chord and it becomes an alteration.

See: C alt.

Very interesting. Is there only one spelling of C alt, or is it a "rainbow" of scales depending on the context?

Can I play an F Major scale over a C7 chord?

[onlyclave]

Originally Posted by MarkTAW

Generally people don't build chords from the vii because the lack of a perfect 5th makes it too unstable. The tones in the chord don't emanate from the root / overtone series. Adding the 5th beneath it making it a V7 chord ensures that all the notes have their proper grounding.

But they don't add the 5th scale degree below it and that's why it is a vii chord and not a V. The first part of your reply explains why vii chords are usually found in first inversion and their resolution pattern is ti-do and re-do for the 2 outer voices.

[GianGian]

Originally Posted by Mushroo

When y'all listen to the blues, and they play I7, do you guys hear that as wanting to resolve to IV (in other words, V7/IV)? What about IV7, does that want to go to bVII (V/bVII)? Or is there something unique about the blues that suspends functional harmony? Now what about the V7 in the turnaround? That really is a dominant 7; when I am playing the blues, is there something special I can do to signal "this time I really mean it!"

Blues doesn't apply...at least that is what I think...blues is like if you are always changing the key, but it still resolves on the "tonic", which is a minor seventh chord...kinda weird...but blues is awesome.

[MarkTAW]

Originally Posted by Mushroo

When y'all listen to the blues, and they play I7, do you guys hear that as wanting to resolve to IV (in other words, V7/IV)? What about IV7, does that want to go to bVII (V/bVII)? Or is there something unique about the blues that suspends functional harmony? Now what about the V7 in the turnaround? That really is a dominant 7; when I am playing the blues, is there something special I can do to signal "this time I really mean it!"

I suspect onlyclave edges me out here in terms of theoretical knowledge.

You can change keys by using various dominant chords, but to make it a really satisfying resolve to really feel like you're in the new key, you have to go through the cycle of fifths by more than a single step. Classical composers use this all the time. If you're in C and you want to get to G, you can't just go to D and resolve go G, you go to A then to D then G.

I suspect Jazz musicians, especially in their use of 7th chords (7th, major 7th and minor 7th, etc.) are more sophisticated than classical musicians. By adding all these extensions & keeping things tonally ambiguous, it provides a rich palette above which to solo. In other words, with things less defined, it allows you to define things more yourself.

[onlyclave]

Originally Posted by Mushroo

Very interesting. Is there only one spelling of C alt, or is it a "rainbow" of scales depending on the context?

Can I play an F Major scale over a C7 chord?

"alt" refers to any/all of the alterations of +9/b9 and/or +5/b5. Add in the natural 11th and you have a chromatic scale.

If your harmony is C7 and you play F major, the chord members in reference to C7(alt) would be F (11th) G (5th) A (13th) Bb (7th) C (root) D (9th) E (3rd). A colorful sound but not as obtuse as it can get.

What if you play E major over a C7? What do those alterations look like then?

[MarkTAW]

Originally Posted by onlyclave

But they don't add the 5th scale degree below it and that's why it is a vii chord and not a V. The first part of your reply explains why vii chords are usually found in first inversion and their resolution pattern is ti-do and re-do for the 2 outer voices.

Ah right, I forgot about viio in inversion. In any case, I'm speaking in broad generalities, and I suspect from a slightly different perspective than you.

[onlyclave]

Originally Posted by MarkTAW

Ah right, I forgot about viio in inversion. In any case, I'm speaking in broad generalities, and I suspect from a slightly different perspective than you.

I thought we were talking about major tonalities where vii is a diminished triad? In C maj that would be spelled D F B (from the bottom up) resolving to C E C (bottom up again).

In C minor the triad built by stacking 3rds on the 7th degree is a Bb major triad which sounds too modal (like Gregorian chant) and has a weak resolution. Raised 7th degree (harmonic minor) gives us the same result as in C major with the same first inversion of vii and the same resolution.

I would still use a viio7 chord in first inversion for the same reason. The 7th of that chord would resolve down by step to the 5th scale degree.