piezo ceramic sensor diameter

I try to make a detector that reacts when the ball hits the net in a tabletennis game.

I do it now with a piezo ceramic sensor of 27mm and it works reasonable fine.
I connect the signal pin to an analog input pin and if the value is greater than 0, I set an LED on for some time.

I see that the piezo ceramic discs comes in a great variation of diameters from 10mm till 50mm.
Wath is the difference between them? To make it more accurate, can I better take a larger sensor or just the opposite?

Many thanks in advance,

Greetings,

Filip

I don't know what you mean by "more accurate". A very important thing is how the sensor is mounted. A wide area for your own experiments, in case you have time to spend for learning.

I think you mean "sensitive" (as in to be able to detect a hit) rather than "accurate" (which would be related to measuring how hard the hit was).

The biggest difference would be the resonant frequency.

I have experimented with the full range of diameters and didn't find a very significant difference between them for my application (detecting a small object hitting a piece of sheet metal).