Although this won't reduce the noise you can add several different sounds that play to add more variety to the audio and make it less annoying. If you want to limit the amount of times the sound is playing at the same time you can use a variable that increases by one whenever the sound is played and decreases by one after the amount of time it takes for the sound to play. If the variable is greater than for example five, the sound does not play. You can also play the sound using a signal to prevent it from delaying any other actions in the event.
Variable = 0
On signal "Shoot" + Variable < 6 -> Signal "Sound"
On signal "Sound" -> Play "ShotAudio"&choose(1,2,3) -> Add to Variable 1 -> Wait (amount of time sound takes to play) -> Subtract from Variable 1
The choose(1,2,3) will only work if you have three audio files, one named ShotAudio1, another named ShotAudio2, and another named ShotAudio3.