(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.
:cool:
