#1
So I'm taking an AP Music Theory class, and now we're doing 7th chords.

According to the student teacher that my actual teacher let cover this part, there are 3 basic forms of 7th chord.

MM7 is a major triad with a major 7th
mm7 is a minor triad with a minor 7th
Mm7 is a major triad with a minor 7th

From when I was learning guitar and I had a book, it didn't describe how they were made, but pointed out 3 7th chords, a regular 7th, a m7 and a maj7.

I'm guessing that MM7 can be shortened to maj7 or M7, mm7 can be shortened to m7, and the M and the m in Mm7 cancel out to give a regular 7.

Am I right? Or was the book wrong and she's right? Or is she wrong and the book right? Considering my regular music theory teacher thought that a quaver was a whole note I don't want to accept anything they say as fact without cross-referencing.
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#2
Dominant 7 (what you're calling regular) = 1 3 5 b7
Example: C7

Major 7 = 1 3 5 7
Example: CM7 or CMaj7

Minor 7 = 1 b3 5 b7
Example: Cm7 or Cmin7

Strictly speaking you could have a minor major 7th chord... 1 b3 5 7. It's not used often though; I think I've only come across it once. Play one and you'll see why.

I've never personally seen them written as MM7, mm7 and Mm7 but it does make perfect sense.

Basically you're both right.
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Last edited by ChrisN at Oct 1, 2013,
#3
Quote by jjfeu662

I'm guessing that MM7 can be shortened to maj7 or M7, mm7 can be shortened to m7, and the M and the m in Mm7 cancel out to give a regular 7.


It's not really about canceling out, so much as the naming convention based on how common the chords are.

Dominant 7ths (major third, minor 7th) are probably the most common, because of their role in determining the key of a song. So it gets the shortest symbol: C7.

Minor 7ths are next most common. They occur on three chords in the harmonized major scale, and are used quite often (in part because of their tendency to "soften" the sadness of a minor chord). So they get the next shortest symbol: Cm7.

Maj 7ths were actually rather rare for a long time - they were considered highly dissonant in Beethoven's time, for example. So they get a longer symbol: Cmaj7.

And, of course, the Major/Minor 7th is very rare, and so gets the most cumbersome symbol: CmMaj7
#4
TS, the problem you're running into is that there's no standard for chord nomenclature (how we label chords). The MM7, mm7, Mm7 your teacher was talking about is one way, and CM7, Cm7 and C7 is another way.

The MM7/mm7/Mm7 version is giving you the quality of the third and seventh in the chord. So the MM7 has both a major 3rd and a major 7th, the mm7 has both minor 3rd and 7th and the Mm has a major 3rd and minor 7th. You might at some point run into diminished sevenths, in which case you'll see dm7 and dd7, which refer to half-diminished and fully diminished sevenths respectively. The letters are now referring to the 5th and 7th of the chord, dm7 has a diminished 5th and minor 7th, dd7 has both diminished 5th and 7th. I really hate this convention because it's cumbersome as shit, but it does make sense. You will never see it outside of a theory class though.
#6
Quote by jazz_rock_feel
TS, the problem you're running into is that there's no standard for chord nomenclature (how we label chords). The MM7, mm7, Mm7 your teacher was talking about is one way, and CM7, Cm7 and C7 is another way.

The MM7/mm7/Mm7 version is giving you the quality of the third and seventh in the chord. So the MM7 has both a major 3rd and a major 7th, the mm7 has both minor 3rd and 7th and the Mm has a major 3rd and minor 7th. You might at some point run into diminished sevenths, in which case you'll see dm7 and dd7, which refer to half-diminished and fully diminished sevenths respectively. The letters are now referring to the 5th and 7th of the chord, dm7 has a diminished 5th and minor 7th, dd7 has both diminished 5th and 7th. I really hate this convention because it's cumbersome as shit, but it does make sense. You will never see it outside of a theory class though.

Maj7, 7 and m7 version also gives you the quality of the third (actually I would say a triad) and seventh in the chord. If it has a regular 7th, it means a minor seventh (because they are more common than major 7ths). A chord with m in front of it is a minor chord and a chord with nothing (I mean, no letters) in front of it is a major chord. You can also have mMaj7 chords.

Oh, and there are other types of 7th chords too. As I said, mMaj7 (minor triad with a major 7th), m7b5 (diminished triad with a minor seventh) and dim7 (diminished triad with a diminished 7th - though I think it's usually just called a "dim" chord without the 7).
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#7
Quote by jjfeu662
So I'm taking an AP Music Theory class, and now we're doing 7th chords.

According to the student teacher that my actual teacher let cover this part, there are 3 basic forms of 7th chord.

MM7 is a major triad with a major 7th
mm7 is a minor triad with a minor 7th
Mm7 is a major triad with a minor 7th

From when I was learning guitar and I had a book, it didn't describe how they were made, but pointed out 3 7th chords, a regular 7th, a m7 and a maj7.

I'm guessing that MM7 can be shortened to maj7 or M7, mm7 can be shortened to m7, and the M and the m in Mm7 cancel out to give a regular 7.

Am I right? Or was the book wrong and she's right? Or is she wrong and the book right? Considering my regular music theory teacher thought that a quaver was a whole note I don't want to accept anything they say as fact without cross-referencing.

Typically the triad is assumed Major and the seventh is assumed minor.

Thus C7 = C major triad with a minor seventh or CMajor minor seventh what your student teacher would call CMm7

CM7 CMaj7 is a C major triad with a Major seventh. We know the Major is referring to the seventh because the triad is assumed Major unless otherwise noted. This is what your student teacher called a CMM7

Cm7 is a C minor triad with a minor seventh. The minor is referring to the triad because in seventh chords the seventh is assumed minor unless otherwise noted. This is what your student teacher called a Cmm7.

There is also a minor7flat five chord or a C half diminished seventh chord, a C diminished triad with a minor seventh.

All four of these chord types are achieved by harmonizing the diatonic scale. But there are more seventh chords that are possible...

Here's my go to post when people ask questions on clarifying seventh chords.

It's a Cut and Paste from a post I made a while back and have recycled a few times and then a few more times in threads since

It starts briefly with how to construct triads then goes through the various seventh chords
--------------

First there are your basic triads. These are made by "stacking" major or minor thirds.

Stacking thirds is easy...


Because the triads are made from stacking major and minor thirds there are only four combinations that we can do and so four basic triads...



Maj 3rd + Maj 3rd = Augmented Triad (1 3 #5)
Maj 3rd + min 3rd = Major Triad (1 3 5)
min 3rd + Maj 3rd = minor Triad (1 b3 5)
min 3rd + min 3rd = diminished Triad (1 b3 b5)

Seventh Chords
To get a seventh chord you then stack another major or minor third on top of the fifth of each of these basic triads to get a seventh chord.

Note that we use whatever kind of fifth we have in our basic triad and add the major or minor third from there. So if we have a perfect fifth we might add a major 3rd the result will be a major 7 interval from the root. If it is a diminished triad with a ♭5 and we add a major third to this we will end up with a minor 7th from the root.

So to get our various seventh chords we go through each of the four basic triads and stack a third on top.

Here are the various seventh chords built using different triads as a base:

Sevenths built from Augmented Triads

Aug Triad + Maj 3rd = Augmented Triad (a Major 3rd on top of a #5 will give a #7. Since the #7 is enharmonic with the octave of the root the result is a doubling of the root note and it's still just an augmented triad. (1 3 #5 #7 is enharmonic with 1 3 #5 8).

Aug Triad + min 3rd = Augmented Major Seventh, or Maj7#5 (1 3 #5 7)

Sevenths built from Major Triads

Major Triad + Major 3rd = Major 7th chord (1 3 5 7) - written as Cmaj7

Major Triad + min 3rd = Dominant 7 (1 3 5 b7) - written simply as C7

Sevenths built from Minor Triad

Minor Triad + Major 3rd = minor Major 7 (1 b3 5 7) - written as Cm/Maj7

Minor Triad + min 3rd = minor 7 (1 b3 5 b7) - written as Cm7

Sevenths built from Diminished Triad

Diminished Triad + Maj 3rd = half diminished 7th or minor 7 flat five (1 b3 b5 b7) - written as either CØ7 or more commonly Cm7b5

Diminished Triad + min 3rd = diminished 7th (1 b3 b5 bb7) - Cdim7 or Cᴼ7

These are the basic triads and seventh chords built from "Tertian Harmony" which means to use maj and min thirds for construction.

Other Seventh Chords
There are also some seventh chords that are altered versions of these chords. That is, one or more notes have been altered and the result is that the intervals between each note are not ALL major or minor thirds, but they are still considered seventh chords.

Dominant seventh sharp five = 1 3 #5 b7 = C7#5 - An augmented triad with a minor seventh.

a diminished/major seventh = 1 b3 b5 7 = Cdim/Maj7 or Cm/Maj7b5 diminished triad with a major seventh.

Dominant seventh flat five = 1 3 b5 b7 = C7♭5

Major seventh flat five = 1 3 b5 7 = CMaj7♭5


Soooo....

That gives a total of eleven different seventh chords.

Here they are again
Seven "Tertian" Seventh Chords
1. Major seventh = 1 3 5 7 e.g. CMaj7
2. Dominant seventh = 1 3 5 b7 e.g. C7
3. Minor seventh = 1 b3 5 b7 e.g. Cm7
4. minor/major seventh = 1 b3 5 7 e.g. Cm/Maj7
5. Half diminished seventh = 1 b3 b5 b7 e.g. Cm7♭5
6. Fully diminished seventh = 1 b3 b5 bb7 e.g. C〬7
7. Augmented Maj7 = 1 3 #5 7 (aka maj7#5) CMaj7♯5

plus Four "Altered" Seventh Chords
8. Dominant seventh sharp 5 = 1 3 #5 b7 e.g. C7♯5
9. Diminished major seventh = 1 b3 b5 7 e.g. Cm/Maj7♭5 or Cdim/Maj7
10. Dominant seventh flat 5 = 1 3 b5 b7 e.g. C7♭5
11. Major seventh flat 5 = 1 3 b5 7 e.g. CMaj7♭5

That's all of them.5

Most are rarely used. The most common are the Maj7, dominant 7, minor 7, and the m7♭5 chords. These four seventh chords all occur naturally when harmonizing the diatonic scales (e.g. when harmonizing the C major scale we get CMaj7, Dm7, Em7, FMaj7, G7, Am7, Bm♭5.

Hope that helps.

A tip - when naming chords (and only when naming chords) the triad is assumed major unless otherwise noted and the 7th is assumed minor unless otherwise noted. Thus if you see Major or Maj then it is referring to the seventh since the triad is already major by default.

If you see minor in the name (m) then it is referring to the triad because the 7th is already assumed minor by default. (The 7 is only minor by default when used in chord names. Outside that 7 always refers to a major seven unless noted otherwise).

Anyway those are the basics of "stacking thirds" to create triads and seventh chords.
--------End Cut and Paste job------------
Si
#8
^ Great post, you explained what I tried to explain way better.

BTW

10. Dominant seventh flat 5 = 1 3 b5 b7 e.g. C7♭5
11. Major seventh flat 5 = 1 3 b5 7 e.g. CMaj7♭5


Aren't those basically the same as C7#11 and Cmaj7#11? (I know a #11 chord has a #11 instead of b5 but they are the same sound - and isn't #11 more common?)
Quote by AlanHB
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#9
Quote by MaggaraMarine
^ Great post, you explained what I tried to explain way better.

BTW


Aren't those basically the same as C7#11 and Cmaj7#11? (I know a #11 chord has a #11 instead of b5 but they are the same sound - and isn't #11 more common?)

Pretty much, yes, since the fifth can be dropped without too much impact on the sonority of the chord.

I was going to put a bit about that in there (some of the chords being more commonly known by enharmonic names, but then I didn't.

I was just working through all the theoretically possible seventh chords.
Si
#10
*longest post*. Very nice.

Found it rather funny how m/M7 was named before diminished and half diminished which are way more common in pop, jazz and classical.

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#11
Quote by xxdarrenxx
*longest post*. Very nice.

Found it rather funny how m/M7 was named before diminished and half diminished which are way more common in pop, jazz and classical.

Yeah you're right. The half diminished is even found in the harmonized major scale along with the Maj7 m7 and Dominant 7th chords. - which are really the four most common seventh chords.

The reason for the m/M7 appears where it does is because I didn't name then in order of how common they are, I named them by grouping them by triad. Thus the seventh chords using a major triad were first, then those built from a minor triad were next, then the diminished triad, and finally the augmented triad.
Si