screwheads.jpgThis is said to work well with the Plug Notching Technique. It certainly has potential to have easily discernible effects, since screws are used everywhere. The technique simply requires that you adjust screwheads so that the slot is parallel to the ground, as in the diagrams of both regular slotted screws and common cross-head Philips screws to your left. Common locations to perform the experiment on are the screws that fasten wall light switch plates, electrical socket plates, plugs, hinges, door handles, locks, shelves, speakers, etc.  I think its clear that if one can perceive positive improvements in sound due to screw head alignment, it certainly can’t be argued that it is due to direct changes in the signal path, or indirect changes affecting sound pressure waves!