Most noise-blocking headphones fall into two categories: they use some kind of material to absorb or scatter noise, or they use active cancellation that creates a signal to oppose the noise signal.
WHAT YOU NEED: A music source with a speaker jack cable, insulated wire and wire cutters, sandpaper, crocodile clips, plastic cup, pen and pencil and a neodymium magnet. Neodymium magnets are very ...