I was thinking the other day, after I had seen OBN's excellent youtube video on installing piezo's in a set of 105 earmuffs, how excellent it would be to utilize the sound-blocking power of the muffs to make a regular set of headphones to use with my ETrac. As a former DJ, I have lots of really robust DJ headphones lying around here and I am wondering if there is enough room in those muffs to install headphone speakers to create my own set of custom made metal detecting headphones...