The Dominant 7th Chord

[dwest2419]

How come in the key of Ab that Eb7 has a minor third in it? Am I wrong going about it this way.

Eb7 = Eb G Bb Db

I try to analyze the interval structure of the chord.

Like I know that Eb to G is a major third but Bb to Db is a minor third am I wrong on this or something

[walternewton]

All dominant 7th chords will have the same "stacked" intervallic structure of M3+m3+m3

C7 = C E G Bb

C-E = major 3rd
E-G = minor 3rd
G-Bb = minor 3rd

[Malcolm]

How come in the key of Ab that Eb7 has a minor third in it? Am I wrong going about it this way.

Eb7 = Eb G Bb Db

I try to analyze the interval structure of the chord.

Like I know that Eb to G is a major third but Bb to Db is a minor third am I wrong on this or something

All that major 3rd, perfect fifth, etc. I found to be confusing so I went another way. Offered for what it is worth.

C scale = C, D, E, F, G, A, B, C
Degree.....1, 2, 3, 4, 5, 6, 7, 8 The 1 is often written as a R signifying the root, helps with generic patterns.

Basic Chords
• Major Triad = R-3-5, C chord = C E G
• Minor Triad = R-b3-5, Cm chord = C Eb G
• Diminished Chord = R-b3-b5, Cdim = C Eb, Gb

7th Chords
• Maj7 = R-3-5-7, C chord with a B added for a Cmaj7 chord.
• Minor 7 = R-b3-5-b7, Cm chord with a Bb added for a Cm7 chord.
• Dominant 7 = R-3-5-b7, C chord with a Bb added for a C7 chord.
• ½ diminished = R-b3-b5-b7, Cm7 with a Bb added for a Cm7b5 chord or C chord with the little 0 with a strike through.
• Full diminished = R-b3-b5-bb7, Cm7 with a Bbb added for a C chord with the little 0 no strike through.

Check this out. http://www.smithfowler.org/music/Chord_Formulas.htm

Which ever way suits you best. A dominant seven chord is a major chord with a b7 added.