You're not crazy... inverse square law. Unless the noise was conducted (or ducted/focused) through a solid (horn/reflector) it would fall off by 80dB at 100m. I

You're not crazy... inverse square law. Unless the noise was conducted (or ducted/focused) through a solid (horn/reflector) it would fall off by 80dB at 100m. In order to get it into a solid you need amazing impedance matching (or alignment)... which also reduces signal. Makes a good story though.