I'm currently looking for a system which can automate a part of my process. Currently, there is an operator listening for sound, which is distinct enough for the human ear. Upon hearing this sound, he shuts down the system. I would imagine that if an ear can easily differentiate the sound, a sensor should be capable of doing so as well. However, I've only had the luck of ONE company coming out so far, and he was unsuccessful at getting his sensor to do so (it was a system originally meant for sounds in a grinding process). Can someone please direct me to a company or a system which might serve my purpose? I have been using google, but my search terms must not be up to par to find what I need.