secondary dominants

[rick-slo]

Just was thinking about some chord progressions in a piece of mine. Key is C major. I use a secondary dominant related to iii chord but returning to the I chord
and another secondary dominant related to and returning to the ii chord. Both secondary dominants are major dominant seventh chords. Is this based on principles behind
the harmonic minor scale? So all secondary dominants of any underlying key are major chords then? Thoughts in 150 words or less appreciated.

[FwL]

Secondary dominants are usually Dominant 7th chords rather than Major 7th chords. Could you outline the chord progressions you're using so we can see better what you're doing?

[rick-slo]

Originally Posted by FwL

Secondary dominants are usually Dominant 7th chords rather than Major 7th chords. Could you outline the chord progressions you're using so we can see better what you're doing?

Sorry, was trying to say dominant seventh of a major chord. Amended my post to "major minor seventh chords". A chord sequence is C-B7-C-B7-C-A7-Dm-G7-C

[FwL]

Piston defined secondary dominants as:

"Any degree of the scale may be preceded by its own dominant harmony without weakening the fundamental tonality."

In other words any chord in the key can have its own V7 chord.

In your progression the only chord acting as a secondary dominant is A7. The B7 is really just acting as a chord borrowed from the relative minor. In order for B7 to be considered a secondary dominant it would need to be setting up an E chord.

In both cases you could see a harmonic minor connection:

B7 - C acting like the V and VI chords of E harmonic minor and A7 - D minor acting like the V and i chords of D harmonic minor.

But that is more coincidence than any real connection between harmonic minor and secondary dominants.

Consider D7 - G7 - C

D7 is acting as secondary dominant to G7. D7 has no connection to harmonic minor in this case.

[rick-slo]

Thanks for the info. Well the nomenclature is interesting. My main takeaway is that secondary dominates are always going to be dominate sevenths of a major (rather than minor) chord.

On chord changes I am usually listening for shared notes and leading tones, and of course the melody line. For example C-B7-C three notes are moving a semitone in parallel down and then back up.

I most often use diatonic chords when I want substitute major chord for a minor chord, or vice versa.

[FwL]

Minor chords can be set up with secondary dominants too.

Look at the common jazz.progression CMaj7 - A7 - Dmin7 - G7 - CMaj7

A7 is a secondary dominant setting up the Dmin7.

[rick-slo]

Originally Posted by FwL

Minor chords can be set up with secondary dominants too.

Look at the common jazz.progression CMaj7 - A7 - Dmin7 - G7 - CMaj7

A7 is a secondary dominant setting up the Dmin7.

I know. I am talking about the secondary dominant chord itself (a major dominant seventh chord, not a minor dominant seventh chord).

[stanron]

Originally Posted by rick-slo

A chord sequence is C-B7-C-B7-C-A7-Dm-G7-C

If you change

C-B7-C-B7-C-A7-Dm-G7-C

to

C-B7-C-B7-E7-A7-D7-G7-C

the chords

E7-A7-D7-G7

are a series of secondary dominants leading to the root C.

A common sequence in 20th Century American music.

Edit; Actually from E7 through to C is a common chord sequence. It's in Five foot Two and Sweet Georgia Brown for example. There may be examples of B7 through to C but I can't think of any off hand.

[Ze.]

Interesting

[rick-slo]

Originally Posted by stanron

There may be examples of B7 through to C but I can't think of any off hand.

My tune naturally: http://dcoombsguitar.com/CDFour/FeelingFreeDemo.mp3

[JonPR]

Originally Posted by rick-slo

I know. I am talking about the secondary dominant chord itself (a major dominant seventh chord, not a minor dominant seventh chord).

Minor keys have dominant 7th chords, same as major.
A "dominant 7th" chord is defined as a "major triad with a minor 7th" - ie a b7.

The word "dominant" simply means the V step of a scale, and the chord built on that step. So the V ("dominant") chord in both C major and C minor will be a G major triad. That means harmonic minor in the case of C minor. But "harmonic minor" is not really a scale, it's simply the practice of applying a major chord on the V step, creating a leading tone (B natural in this case).

In short, this means secondary dominants are always the same chord type, whatever chord they're leading to. And they don't have to include a 7th, except in one case.

Secondary dominants in C major:

D = V/V, leads to G
A = V/ii, leads to Dm
E = V/vi, leads to Am
B = V/iii, leads to Em
C7 = V/IV, leads to F.

In the first 4 cases, the major 3rd of the chord is the essential chromatic note, leading up by half-step to the following root. (You can add a 7th to any of them, but the 7ths are all diatonic to C major; they don't change the chord function, they just enhance it.)
The C7, OTOH, needs the chromatic Bb to lead down to A on the F chord, otherwise it's just "I", not "V/IV".

It's common for secondary dominants to be used in "deceptive cadences". The most common is for E (or E7) to lead to F instead of Am. But that also applies to your B7 leading back to C instead of Em.

They can also lead to another secondary dominant - such as E7 to A7 - but that move is not regarded as "deceptive" AFAIK.

Secondary supertonics

"Supertonic" is the fancy word for "ii". These are common in jazz, and is where you start to see the differences according to what chord is the target of the dominant. So, those secondaries in C major might appear as follows:

Am7-D7 = leads to G
Em7b5-A7b9 = leads to Dm
Bm7b5-E7b9 = leads to Am
F#m7b5-B7b9 = leads to Em
Gm7-C7 = leads to F.

So when the target chord is minor, the secondary ii chord will probably be a m7b5, and the dom7 may have a b9 (or some other alteration). These chords imply the harmonic minor of the target chord, which will work fine, but jazz theory (if not always jazz practice) advises other scales for those 7b9s (altered or HW dim).

[rick-slo]

Thanks for the info. I usually pay attention to shared notes and leading tones by ear rather than thinking about named conventions, but sometimes I am interested in looking at other analysis angles.

[jseth]

The most salient explanation for much of "Modern Diatonic Harmony", especially the more advanced stuff, was given to me by the fellow who taught me what I know about harmony and theory...

Martin was the pianist in our band and had recently graduated from the Berklee College of Music in Boston, MA... this was back in the mid-70's... he was, and is, an extremely gifted player and composer. In a 6th level harmony class, they were working on some aspect of functional re-harmonization, when the teacher said,

"You have to remember that all this stuff is the result of a bunch of white intellectuals trying to explain why the Blues works..."!!!

I've always loved that comment, and refer to it whenever I start getting tangled in that web of theory...

My understanding is that dom 7th chords can be used (and justified intellectually!) ANYWHERE that they sound good to you! Certainly secondary dominants would be one of those times... but it all comes down to what you hear and what sounds "right" to you...

[JonPR]

Originally Posted by rick-slo

Thanks for the info. I usually pay attention to shared notes and leading tones by ear rather than thinking about named conventions

Good idea! Keep it up!

Originally Posted by rick-slo

, but sometimes I am interested in looking at other analysis angles.

OK. Usually that's just about discovering names for stuff.

[JonPR]

Originally Posted by jseth

"You have to remember that all this stuff is the result of a bunch of white intellectuals trying to explain why the Blues works..."!!!

Well, if it really was the Blues under discussion, then yes that's a little crazy. (Fun, maybe, for a certain breed of intellectual, but not in any way instructive.)

Blues harmony is non-functional, according to the standard (originally classical) harmonic theory of which secondary dominants are a part.

Bebop musicians did - habitually - graft functional harmony on to blues sequences, probably to show off how well they could negotiate the changes (and scare off the competition). Those changes will usually align with standard harmonic theory, including secondary chords and what jazz musicians call "tritone subs", but classical analysts would probably call "augmented 6ths".
As I said above, this is all just "names for stuff", and doesn't really "explain" anything.
Music theory doesn't even explain why the music it describes works, so it certainly won't explain why blues works.

(The point of music theory is not to explain; only to describe. Descriptions can sometimes feel like explanations, but they aren't really.)