Augmented dominant seventh chord = what scale?

Question

An easy example: `C+7 = C E G# Bb` What scale would this thing come from? When playing it it sounds lydian to me, not so much dominant. Same notes rewritten: `E+7#11 = E G# B# A#` my best guess would be lydian augmented mode from `III` melodic minor... but that mode doesn't have a `b7`...

Answer 1

C whole tone = C D E F# G# and A#(Bb)

C altered = C Db Eb E Gb Ab and Bb

My choice would be C altered. You mentioned the melodic minor scale.

The altered mode is the seventh mode; in this case Db melodic minor, where G# is the sharp 5, or lowered 6.

We have no avoid notes in melodic minor harmony, thus the chords are interchangeable and can provide different sounds depending on voicings and what note is used as the root.