Abstract: A stereo headphone having left and right headphone units which are connected to a binaural input plug that has left and right input cords respectively connected between the left and right headphone units and wherein the right and left input cords are connected together in parallel between the binaural input plug and a predetermined intermediate point and with a muting switching device mounted at the intermediate point so as to allow muting of both headphone units under selected conditions.

Abstract: A headphone having a speaker unit having a diaphragm and a supporting member for supporting the speaker unit so as to face forwardly of a user's head with projection of an edge portion thereof into the cavum concha whereby the speaker diaphgram faces to the entrance of a user's auditory canal with the sound radiating direction thereof.

Abstract: A speaker unit for headphones including a magnetic circuit which has a magnetic gap and including a diaphragm which is moveable to generate sound in response to energy applied to a coil wound on a bobbin which is connected to the diaphragm and mounted within the magnetic gap and including a frame for supporting the magnetic circuit and the diaphragm and a protecting means mounted at the front of the diaphragm and having projections so as to engage the diaphragm near the region where the bobbin is mounted so as to limit the maximum motion of the diaphragm and the protecting means formed with openings such that the protector prevents the bobbin from moving completely out of the magnetic gap. The invention is applicable to speaker units for open air type headphones, for example.