Sevenths

Can someone answer this question? What's the difference between a 7th chord and a minor 7th chord? Let's take the key of D. A Dmaj7 flats the root note (D) to a C# (or Db). So it's based on the major scale, adding in the major 7th note, the C#. But what scale is used in the good old regular D7? The D minor scale? I have a few beginner students and I don't know how to explain the scale that you would play to count out the 7th note to construct the "regular" 7th. The difference between D minor and D minor 7 is a whole step down from the root (to C), but what scale is a D7 based on? Is it based on a mode of D maj? It also is a whole step down, but the rest of the D7 chord isn't minor. Can ya help me??

Ok, the old school answer, i.e.. (unschooled), is first off, DMAJ7, does not contain a flatted root(c) but the natural 7th scale tone C#, DF#AC#, which are all in the D major scale, Dmin7th, is DFAC, the C is the 7th in the Dmin7th chord, now here's an answer to the scale mystery, if you are playing in C Major, then Dm7th fits into your scale CDEFGABC, now start on the 2nd degree of that C scale, changing the root of the scale to D, play DEFGABCD, you are now playing in one of the minor modes, but I can't ever remember which one, maybe Dorian or Chick O Fillian, or sumptin like , does that help? or make sense? I hope it helps

Look at your Chord spelling for the D7, DF#AC, the F# is the major 3rd, so you know by that, you must be in a major scale, so again look at the chord spelling, there are 4 notes and you only need 3 more, think of a scale that contains those 4 notes, times up, GMAJ, GABCDEF#G, play that scale starting on the 5th, DEF#GABCD, I believe thats D Mixolydian, stangely it has a 7th kind of sound, and works pretty good for those country rock type o things, I believe you'll enjoy it's delicate bouquet, and nutty yet playful flavor, I've used up all my limited mental abilities now, so I must recharge, .... . . . . . .

To answer your questions:

(1) the difference between a 7th and minor 7th chord is that the minor 7th chord contains a minor 3rd. The Dominant 7th chord contains a major 3rd.

Dom. 7th = Root, 3rd, 5th, b7th
minor 7th= Root, b3rd, 5th, b7th

In your example using the D Major scale:
(D, E, F#, G, A, B, C#, D)
(R, 2 ,3 ,4, 5, 6, 7, R)

D7 = D, F#, A, C
Dm7 = D, F, A, C

(2) You do not flat the root note of the Dmajor scale to get the C# in the D major 7th chord. The D major 7th chord is constructed with the Root, 3rd, 5th, and 7th tones from the D Major scale. C# is simply the 7th tone in the Dmajor scale. DMaj7 = D, F#, A, C#

(3) What scale is the D7 chord based upon? Well, it depends on how you look at it. I like to look at it like this: The D7 chord is derived from the G major scale. G, A, B, C, D, E, F#, G
The note, 'D' is the 5th note of the G Major scale. All of the notes in the D7 chord are contained in the G major scale. D, F#, A, C.
Now you may here people refer to the mixolydian mode, or that the D7 chord comes from D mixolydian. That is correct, but D mixolydian is also derived from the G Major scale. The mixolydian mode is the 5th mode of a Major scale. D Mixolydian would be the 5th mode of the G Major scale. To simplify, if you play a G major scale starting on the note 'D' (D, E, F#, G, A, B, C, D) that would be D Mixolydian. Notice that all of the notes in D mixolydian are contained in the G Major scale. The starting point for playing the scale is the only difference.

(4) The Difference between D minor and D minor 7th is simply the addition of the minor 7th. D min= D, F, A. Dmin7 = D, F, A, C. D minor and D minor 7th are derived from the C Major Scale.

This is the beauty of theory, one question, many ways to give an answer, I believe trebledamage got straight to the heart of the matter, and the old saying still rings true, there's more than one way to skin a monkey

Thanks pstring and trebledamage for your input. Let me recap in words that a beginning student might be able to grasp. Based on what trebledamage said in point #3, take the 7th note of the mixolydian mode and add it to arrive at the "regular" 7th chord. Would you agree? I'll save the relationship to the Gmaj scale for later. LOL's to pstring's humorous evaluation of the esthetic qualities of the mixo mode! It's one of those modes that we use all the time, and learn what it's called much later. That info does help, but it leaves me with a new question: why call that chord simply D7? Why not call it Dmixo7? Once again, Thanks!

With a beginner student, I would initially just tell him or her that notes from the G Major Scale will sound in tune if he or she is soloing or playing a melody over the D7 Chord. If the student asks why? I would tell him or her because all of the notes that make up the D7 chord are contained in the G Major scale. That is about as simple as you can put it. The raising and lowering stuff will only confuse your student. I would focus on having that student learn the Major Scale through the circle of 5ths before introducing modes and all sorts of altered forms. It's like, you can't start building a house before you pour the foundation.

Thx, td. How would you incorporate the theory of the Roman numeral numbering system to this concept, (I, IV, V, etc)? I'm trying to tie it all in by introducing numbered scale notes to the I, ii, iii, IV, V, vi, vii and playing major or minor chords within a key to identify or write songs. Am I tackling too huge of a piece of theory too soon? I want my students to get a fair helping of chords, scales, and theory at each lesson.

And since you've been so gracious, here's a slightly unrelated question: why do we mix the sharps and flats when we name the notes going up the fingerboard? (EFF#GAbABbBCC#DEbE) Some of my students who have prior music (piano) experience say you only use all sharps or all flats in a given key so you can still use every letter name?

At this point, you're probably thinking, "And he's a teacher?" I figure with 7 students, it's time for me to get it right! Thanks again.

The Roman numeral system is just another way of referring to the chords derived from a given scale. I will use the C major scale as an example: C, D, E, F, G, A, B, C. All seven tones in the C Major scale can be "arpeggiated" to create corresponding chords, all of which are related to the C Major Scale. Each one of those chords is given a corresponding Roman Numberal: I, ii, iii, IV, V, vi, vii. The 'I' chord always makes a Major 7th chord. The ii and iii always make a Minor 7th Chord. The IV makes a Major 7th Chord, the V makes a Dominant 7th Chord, vi makes a minor 7th chord and the vii always makes a minor 7 with a flatted 5th. Lowercase roman numerals are used for 'minor type' chords. Uppercase roman numerals are used for 'Major type' chords (Major and Dominant Chords)

Using the C Maj scale:

I = CMaj7 (C, E, G, B)
ii = Dm7 (D, F, A, C)
iii = Em7 (E, G, B, D)
IV = FMaj7 (F, A, C, E)
V = G7 (G, B, D, F)
vi = Am7 (A, C, E, G)
vii = Bm7b5 (B, D, F, A)

So, for example, when you hear people referring to the ii, V, I progression (typical jazz chord progression) They are referring to a progression which will use the ii, V, and I chord derived from a given Major Scale. Using the C Major Scale, a ii, V, I progression in the key of C would involve the Chords Dm7 (ii), G7 (V), and CMaj7 (I). If you played any notes from the C Scale over that progression, they would sound completely in tune since all of the notes in the above chords are contained within the C scale.

As for the use of sharps and flats, some notes will be listed with more than one 'name' (F#, Gb) because both types of terminology are necessary when you are forming scales and chords. You don't see both sharps and flats used when forming the basic major or minor scales because using both sharps and flats could violate the rules necessary to denote different scales and chords. For an example of what I'm talking about, check out the posting titled Bb7(13). James talks about the notes necessary to form that chord. (Bb, D, F, Ab, G). A book he read indicated that there was a G# in the chord. That is not true. Although (G#, Ab) have the same sound, they are not the same note. G# would be a note based on the 6th tone of the Bb scale. Ab is a note based on the 7th tone of the Bb scale. A Bb7 chord involves the Root, 3rd, 5th, and FLATTED 7TH, not the raised 6th. Its mostly semantics, but to refer to the notes incorrectly in a given scale or chord could make things completely confusing. Now there are more exotic scales and more complex chords which may contain both sharps and flats, but since you are working with beginner students, they don't need to concern themselves with that right now.

[Edited by trebledamage on 12-12-2001 at 05:30 PM]

Originally posted by StratsGalore
What's the difference between a 7th chord and a minor 7th chord?

Here's the simple answer to this question - dominant 7th chords are built off the 5th (V - dominant) tone of the major scale. For D7, go to the G major scale, and count up the 1st, 3rd, 5th, and 7ths tones from D. If you've done it right, you should get D F# A C. Minor 7th chords are built off the second tone (II - supertonic) of the major scale. For a Dm7, go to the C major scale and count up 1,3,5,7 from D. You'll get D F A C.

Basically, the difference is which scale tone you start on. The second tone of the major is scale is dorian (minor), so you get minor triads when you count up. The fifth tone is mixolydian (major), so you get major triads.

Ok . . . maybe that wasn't so simple. But it's the way I think about it from piano. In music theory, there's a lot of different ways to visualize the same thing. You just have to find the way that works for you.

Stratsgalore is now sitting in the corner, twitching and trying to catch imaginary butterflies, see what we have done to the poor guy. I think Christoph brought up a good point, in saying it all depends on which scale tone you start with. Maybe a book on theory is something you might want to check the local library for, cheers!

twitch...twitch...

Maybe I'll take up tennis...

But seriously folks, thanks for all the input. I have to take it all in and put it into practice. I'll get it eventually. I'm off to the library - or Julliard.

pstring is right. You should pick up a book on music theory. As someone else mentioned on another posting, Scales and Modes, In the Beginning by Ron Middlebrook (I think that's the author's name) would be a good place for you to start.

Yeah, that's a great book, and unlike most theory books, it's actually written for guitar players!

a book written for guitarists! unless it has alot of pictures and diagrams, that's a project I would never invest in! Ron Middlebrook must be a brave soul

Chords are made using every other note of the scale. Due to the spaces in the scale, a dom 7th can only be formed from the fifth note of the scale. There is only one major scale where D is the fifth note and that is the G major scale.