The main ingredient of a Dom7 chord is the 3rd degree. Or.... the main ingredient of a Dominant chord is the 3rd degree.
The 3rd degree is the leading tone to the home tonic chord.
Take the Key of D for instance.
the dominant triad is A. The notes of a Major are A C# E....... Notice the 3rd .. C# is the leading tone to D. That is what really makes a dominant chord.
Next up and specific to your question is the 7th degree. The 7th is always understood to be b7 unless otherwise specified.
Sooo.... people will call Am7 and A7 dominant chords. However if you say the chord aloud you say A minor 7 or A dominant 7.
Dominant chords are always Major. You can't have a b3 that will a leading tone. so even if you are in a minor key. the Dominant chord is major and has a major 3rd degree.
X7 = Major chord with b7 = real dominant - hard resolve
xMaj7 = any sort of chord with a major 7th degree - could be dominant or not - weak resolve if minor type
That's really all you need to know. Is my 3rd flat or natural. Is my 7th flat or natural. All that other stuff is just tacked on and in fact some of it is dropped off. You generally think in terms of building the entire chord like 1 3 5 or 1 3 5 b7 or 1 3 5 b7 9 but in reality when you keep adding on you generally might only play 4 strings so you drop stuff off and play the essence of the chord OR maybe you have a really big chord but several instruments play parts of it. Maybe the guitar plays a 13th and 9th note, the bass plays the root and 5 and keys or second guitar catch the rest. So collectively a big chord was played.
Again you are dealing with the same thing 2 4 6 9 11 13. the only thing left is how the 3 and 7 are handled. Well the 5 but again that would show up in the chord name for sure if it was b5 or #5.
Dominant = 3rd degree leading tone to tonic.
Topic: concept behind dominant7 chords? (Read 4091 times)
