Originally Posted by 1971BB427
That's correct, and the round tip shaped blades were developed to quiet down the fan noise. They still move air well, but cut down the noise factor. Try to find fans with the rounded tips on the blades, and they'll be quieter. Grainger has a pretty good variety of fan styles. You'll notice anything labeled "quiet" has rounded tip blades.
Air Circulators - Circulating Fans - Grainger Industrial Supply
Wow! Not inexpensive.
I wonder if there is a source for the blades to retrofit existing fans.