Sometimes finding interesting substitutions for a Dominant 7th can lead to some new melodic material and some fresh inspiration in a common harmonic environment (Dominant 7th). This exercise uses Major 7 (#5) descending by major 3rds over one dominant 7th chord to create an idea that sounds colorful and different than a standard Lydian Dominant melody.
Over C7 the melody will outline Bb Major 7(#5), Gb Major 7(#5), D Major 7(#5) and back to Bb Major 7(#5). By playing a sequential motif grouped in 5 over this descending Major 7(#5) progression, we get an interesting melody that still sounds like C7 yet introduces some well organized approach notes and/or tensions (nat 9, b9, nat 11, #11, 13). The exercise is played in eight-notes and than again in triplets. The PDF contains a more detailed explanation of both the Major 7(#5) substitutions and the groupings of 5.
It’s also interesting to notice that the entire melodic/harmonic phrase comes from the (classical) augmented scale: over C7 the Bb classical augmented scale is Bb Db D F Gb A Bb (which is comprised of 2 augmented triads a half step apart: Bb augmented triad and A augmented triad). This melodic exercise works over major and minor chords as well… The melody that I’ve associated with C7 could therefore be played over Bb Major 7, Gb Major 7, or D Major 7 or their relative minors; G minor, Eb minor and B minor. The options are limitless once you add some rhythmic variation.