Show off your theory chops with my weekly challenge! You’ll find a new question here every Monday. Please comment to post your reply.
This week’s challenge:
In last week’s challenge we said hello to this Phrygian cadence in Bach’s Toccata and Fugue in D minor. This week, what type of chord would you get if you sharped the root of the iv6 chord? Careful: make the root sharp, not the bass:

ANSWER for 6/21/21

Those of you who crossed the Alps for an Italian holiday: CORRECT! By sharping the root of the iv6 chord in a Phrygian cadence, you end up with an Italian augmented sixth chord. And this is very likely the origin of the Italian 6th: a chromatically embellished Phrygian cadence. Listen to both:
This B-flat Italian 6th is enharmonic with a B-flat dominant seventh chord, but the sharped root is spelled G-sharp, not A-flat. And spelling makes all the difference. When you hear how this chord resolves (the augmented 6th goes outward to the octave), that’s when you can distinguish it from a Bb7.
This summer I’m creating a whole new module for the Breaking Barlines course: Chromatic Harmony! Sign up for a monthly subscription for full access to all video lessons, worksheets, and answer keys. Also, this year I’ll be adding new lessons on modes. I created Breaking Barlines with one thing in mind: making music theory effective and FUN!