The tones below were generated using a signal generator connected to a speaker and measured with a frequency counter so they are correct to high accuracy. They are “perfect pitch” notes and somewhat colourless but you might be able to match them to racquet and string sounds, or to hollow bat sounds, depending on whether you have good hearing. If you are tone deaf then they won’t help at all, but some professional tennis players have been known to match the sound of their strings with a tuning fork.
Tennis strings ping (vibrate) at about 500 to 700 Hz
Baseball bats ping at aboout 1000 – 2000 Hz
Racquet frames and wood bats vibrate at about 130 – 200 Hz, but you need to put your ear close to the handle to hear them, and hold the racquet or bat lightly about 6 – 7 inches from the end of the handle, so as not to damp the vibrations.