Diaphragm

In a loudspeaker, a diaphragm (generally, but not exclusively cone shaped) is the thin, semi-rigid membrane attached to the voice coil, which moves in a magnetic gap, vibrating the disphragm, and producing sound. Diaphragms are also found in headphones, and microphones.

Similarly, the eardrum uses this same principle, using a diaphragm to stimulate nerves to transmit a neural "image" of sound to the brain. In loudspeakers, cellulose fiber (paper) has histroically been the most common material used for the diaphragms, based on its low mass, and controllable acoustic properties. Synthetic fibres and binders may be added to provide specific properties. Other materials used for diaphragms include: polypropylene (PP), polycarbonate (PC), Mylar (PET), silk, glassfibre, carbon fibre, titanium, aluminium, aluminium-magnesium alloy, and beryllium.