I spoke to Bob today about my
singing fin... The 10 inch McTavish Single Fin sings to me when I lay over a hard bottom turn at speed. I really like the sound. It's more like a Tuning Fork but at a low/medium frequency. The harder I turn at big speeds, the louder and higher the pitch. The fin sings! Bob mentioned that there could be a flat spot on the rear trailing edge.
I'm a happy surfer right now. Plenty of quality point break sessions, high wave counts, beautiful equipment, with lovely a singing single fin. Plus I feel like I'm surfing the best I have ever surfed, and my bottom turns feel really nice. What more can you ask for!?

Anyway, so I took a closer look at the rear trailing edge, and sure enough, it's a little bit square/flat through the middle, and a tiny tiny bit square through most the entire trailing edge. Bob said sand it back and she'll be right! But to be honest, I love the singing! Plus I don't want to hone off the polished finish.
I'm just happy to be taking my equipment into the upper echelons of speed through the
racetrack section at Winki-Pop right next to Bells.