Abstract
When a loudspeaker is used as the laboratory standard, following characteristics are required: 1) The response-frequency characteristics is to be monotone. 2) Response is not to be affected by temperature and humidity. 3) Amplitude distortion is to be small. Since the response of a paper-cone speaker fluctuates by the variation of temperature and humidity of the room, it cannot be used as a laboratory standard. Therefore, a loudspeaker for laboratory use, was designed employing metallic titanium as the diaphragm material. The fluctuation of response due to the variation of temperature and humidity was very small and the response-frequency characteristics was flat over the range of 50 c/s to 10000 c/s. In designing the cone, calculations were made so as to make the frequency characteristics of sound pressure on the front axis to be flat when a constant driving force is applied to a mass-controlled piston diaphragm.
