# What makes tennis loud popping sound?

## Main Question or Discussion Point

Hi,
When I hit the ball on the center of the racquet face,

it will make a loud popping sound, less off the center.

Why's that?

Is this sound related to the strings, the ball, or the racquet?

Will different strings, string tension, string pattern, ball hardness,
ball felt , hitting power, racquet face angle to the ball...make the sound different?

I can't get an answer scientifically in some tennis forums.

Thank you so much ^_^

YKD

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Danger
Gold Member
I suspect that it's just the displacement of air as the ball rebounds to its normal shape after having been partially inverted by the impact with the racquet. That's just a top-of-my-head impression, though.

its all that grunting they make. UGHHHHHHHHHHHHHAAAAAAAAAAHHHHHHHHH.

Its probably the rubber being compressed inside out and then 'popping' right side out again.

Thanks Danger and Cyrus!
The popping sound won't be made when the ball is hit on the ground.
It should be related to the strings and the ball,
but I have no idea why it is.

Now, when I hit the ball, I just see a sudden flash of light, and both the ball and my racquet disappear.

^^^ Pro right here

The harder a ball is hit on any surface, the louder will be the sound of the ball hitting the surface.

But the actual poppiness of the sound is created by strings.
Not sure how.

Danger
Gold Member
Actually, the sound is made if you bounce the ball off of pavement. It's a little different, but that can be attributed to the way that racquet strings distribute sound waves.

rcgldr
Homework Helper
Must be the strings, since the rate of acceleration of the ball is the slowest at the center of the strings, but the elasticity is greater. Try hitting a tennis ball with a baseball bat and compare the sounds.

The strings are probably probably being displaced a bit, causing them to slip, overcoming the static friction between strings, and this sudden movement of the strings, amplified by the racket head is probably making the sound.

try hitting different types of balls. try for example a shutle coff it still makes the popping sound but at a different frequency. it has to do with the weight of the object that has been foced into the strings on the racket. it is basically a sum up of the other people replying to this but i hope this helps.

Thank you all ^_^
yes, the sound is of lower frequency when the ball is hit on the ground.
The center of the strings is the greatest elasticity compared
with the outer,
but in fact, the stringbed is quite hard because of high string tension,
so the string slip should be very less.
And one thing I got is that when the racquet face is 90 degree
to the ground,
no spinning of the ball, and hit harder, the popping sound is great.
Maybe it's the most right angle, right place(stringbed center)
right hardness of the ball and right power for the string vibration
(back and forth) for a certain frequency (loud pop),
which hz?
Similar to guitar or violin? I am not sure...
Hope someone will find the concrete and scientific answer.^_^

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