Show off your music theory chops with my weekly challenge! You’ll find a new question posted here every Monday, and you can comment to post your reply.
This week’s challenge:
How should you spell the note names for this A flat half-diminished seventh chord (for you jazz cats and rock hounds, that’s an A flat minor 7 flat 5). Then, respell the chord as a G sharp half-diminished seventh!

Check back on Friday, May 14th for the answer. Fear no harmony!
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ANSWER for 5/10/21


Chords are always spelled in thirds, which means their notes have to skip letter names. When you write a chord, always start with just the bare letter names, and add the accidentals later. For an A flat half-diminished seventh chord, the letter names are A–C–E–G. That’s what we’re stuck with, and the letter names can’t be changed. So the correct spelling is A flat, C flat, E double flat, and G flat.
Obviously, no one much cares for this spelling! That’s why you’ll more commonly find this chord spelled enharmonically as a G sharp half-diminished seventh. Keep in mind, B and C flat might be the same pitch, but they’re not the same note. Think of homonyms like their and there: two different words, with two different meanings, that happen to sound the same.
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Ab Cb Ebb Gb
G# B D F#
You’ve got it! All spellings are correct, right down to that crazy E double flat. Way to go!
Ab, B, D, F#
G#, B, D, F#
Hi Steve! You’ve got the G sharp chord spelling correct, but the A flat spelling is more challenging. The best way to spell chords is to start with the letter names only, no flats or sharps. Chords always skip letter names, so it would be A–C–E–G. Now, when we put in the flats, we have to stick to those letter names. So it’s A flat, C flat, E double flat, and G flat. Even though B is the correct pitch, it has to be called C flat in order to be spelled as a third above A flat. A flat up to B, while sounding like a minor third, is really an augmented second.
It does get tricky, but you did well! My video lessons in the chord and fundamentals modules tackle just these issues in music.
By me, the spelling of a diminished, or half-diminished chord is determined by where it’s going. The Abm7b5 chord contains the leading tone for C, and you’d spell that as B-natural. The G#m7b5 resolves to A. One should spell each chord in such a way as to have the least number of accidentals. (I was able to paste a screenshot on Facebook, but not here)