One of the best aspects of working with Jim Horne on XWord Info is discussing puzzles. We often have a very different take, and sometimes he completely changes my opinion with thoughtful reasoning. It was only through some back and forth with him that made me realize there were enough things about today's puzzle that I loved; well worth the liabilities. Overall, it's POW material.

The concept will be rough for non-musicians, as the idea hinges upon knowledge of the chromatic scale. Each note can be described in two different ways, i.e. G sharp is equivalent to A flat. If only it were consistent all the way up! There are a few notes like E and F which are only a half step apart, so E sharp is not equivalent to F flat … but to F natural! Confusing, isn't it?
What finally flipped my thinking was Jim's visual interpretation (see the answer grid below). I can often take care of grid fixes, but this one was beyond my capabilities. I love the way it looks, so elegant, much more so than writing F NATURAL all into one little square — where I already had E SHARP already written.
I did have some issues. ENHARMONIC describes perfectly the idea of one note described in two ways … but it's in such an odd location, just off the centerline of the puzzle. That would have been perfectly fine if the symmetrical entry had also been thematic, but STORE SIGNS doesn't relate.
I also liked the presence of MUSICAL NOTE, but TWO TONE CARS didn't do it for me. I can see how it hints at the concept of a single tone being describable in two ways, but it doesn't feel very apt.
There was a little bit of crossword glue needed to hold things together (RESOAK, I see you), but that's not surprising considering three pairs of long crossing answers. And some great fill in FANGIRL, CURE-ALL, FELLINI, QUIT IT and I ROBOT really enhanced the solve.
So all in all, a great idea and a lot of colorful phrases overcoming the problems I had with it.
ADDED NOTE: Astute reader David Jones noted (pun intended) that STORE SIGNS actually hints at a box "storing" a musical sign. Subtly clever!