another way of looking at it could be as an augmented 4th (C to F#) or a diminished 5th (C to Gb). As you can see, these are all different names for one specific sound. Once we get into chord ...

In the jazz styles of Gershwin and Kern, the dominant seventh was often substituted with an augmented chord.This gave the tonic-dominant a new and modern feel. This can be heard in Can’t Help ...