Abstract: A bed adjustable in hardness distribution of its surface. An elastic member is interposed between a surface side member and a bottom plate of the bed, and the bottom plate is divided in the direction of its plane and each of the bottom plates thus divided is made vertically adjustable to allow the internal pressure of the said elastic member to be changed, so that the internal pressure of each part against the urging force from the surface is changed and the depression amount of the bed surface becomes uniform.

Abstract: A headphone having a pair of microphone-loudspeaker units interconnected by a clamping strap for holding the units against the ears of a wearer. The loudspeaker and a microphone of each unit are isolated acoustically from each other by an enclosure. The enclosure is formed with a generally semicylindrical surfaced portion to simulate the human earlap and a flat surface normal to the semicylindrical surface. The microphone is mounted on the flat surface with its main direction of acoustic sensitivity oriented to a dummy earlap to receive a sound wave reflected therefrom.