You're checking for peak amplitude every millisecond. So you're getting many more bangs than you probably think you are, and many of them are only 1 ms apart. The timer is working fine, but the part of the patch above that needs some revision.

For example, once the amplitude threshold is passed (and you get one bang) you might want to stop sending bangs until the peak amplitude has been below the threshold for a certain amount of time (say, 50 ms or so at least).

I know that's coming a little too late but thanks a lot, Christopher! Back at the time this helped a lot! :D

Best, Anton