U.S. Open (tennis)- why are Federer and Andreev's serves sounding like they're brushing the net on practically every serve?

Man, you’ve really got your surround sound cranked. But it CAN’T be, what with all the sensors all over the place. I just love how they track the balls these days. It’s fascinating.

They are serving at speeds near to 150mph, so is it possible that the air displaced by the ball makes this noise as it passes?

Could be the contact of the ball on the strings, if they have particularly spinny serves. With the speeds they are hitting, it could easily look like the sound is coming from a net cord.

It’s the air displacement that causes it, happens to me while playing. We finally put a couple guys all over the net and served a couple and the were watching from about a foot or two away, the balls wasn’t near the net, a couple inches about, but they all heard the ‘brushing’ sound.

I know though that Andy Roddick has actually set the sensor on the net off and it clearly didn’t touch it. The official told him, if the sensor goes off it had to hit, the wind wouldn’t set it off. If we’re going to have the challenge system, I say allow a challenge on a call like that. =/

Anyways, the speeds of the serves do play a roll in the ‘brushing’ sound and more air is being displaced than people tend to think. =)