Anyone notice that a square-tipped blade makes more noise than a rounded tip?

I ask because I took out my two homemade GPs on Sunday morning. The one with the round epoxy tips (with extremely sharp edges) was whisper-quiet. The one with the walnut tips/edges was a bit noisier--made that scraping sound in the water sometimes. I'm suspecting it's the presence of corners on the latter paddle, although its edges are also less sharp.

BTW, one advantage I discovered of having very sharp edges is the ability to shake off or cut through hydrilla/kelp/whatever that nasty river grass is that's clogging up the Potomac right now. I somehow ended up in the middle of some, but I was able to paddle out without too much effort, but ending each stroke with a vertical up-sweep, which shook off the river grass.