Everything said sounds correct to me.

To add to the discussion:

An alt chord is primarily used to create tension. The dominant chord when it has a dominant function already creates tension and makes ones ear expect and/or enjoy the resolution (generally to a chord a fifth below and often to the tonic). Adding the altered notes to a dominant 7 chord increases the tension and the subsequent sense of resolution.

One way of thinking of it is that the altered chord is made up from the notes of the altered scale (the altered scale also creates tension). The altered scale is made up of the:

1 b2 b3 nat3 b5 #5 b7, or another way and probably better way to write that is by using these enharmonic equivilents:

1 b9 #9 3 b5 #5 b7

If you start with the 1 3 b7 for your dominant chord, you can then add any one of those other notes or more than one of those other notes to create an alt chord.

C7b9 C7#9 C7b5 C7#5 C7#5#9 etc. All of those are altered dominants derived from the altered scale.

And a great choice of a scale to play over any on those dominant altered chords is the, you guessed it, the altered scale. In the case of those C7alt chords listed above.

1 b9 #9 3 b5 #5 b7 or C Db D# E Gb G# Bb

Also, the altered scale is the seventh mode of the melodic minor. In other words the C altered scale is the same group of notes as the Db melodic minor scale.

(Perhaps more than most would want to read or as Zappa would say, "Shut up and play your guitar")

Last edited by Frankp; 10/24/13 08:23 AM. Reason: correct an error, 7 changed to b7
Frank

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