Regarding the french augmented sixth chord: The chord is used in cadences. In the key of c, the French augmented sixth chord would be Ab-C-D-F# leading to the 'clean V' (as I call it), G-B-D-G, or even better, the Gsus4. The most common use of the augmented sixth chord (google it if you're into nerdy music theory) is the German augmented sixth chord; Ab-C-Eb-F# (in the key of c), that then leads to the cadential dominant 6/4 chord (G-C-E-G) that leads to the 'clean V' and finally to the tonic of c. As a professional classical musician, the German aug. sixth chord is by far my favorite chord (in cadences), so I guess my question is; now that you know about it and you're good at writing catchy jingles, would you consider using it in your music?
i think i already have