Abstract
Various methods for binaural stimulation of animals (cats) were reviewed and discussed. A detailed description of our apparatus for binaural stimulation and of the method of calibration was given. The apparatus is a pair of earphone systems consisting of the metal earpiece, the portex tube and the dynamic earphone (Toshiba, TR-33). The output of the earphone was indicated by the sound pressure level of free field stimulation which produced an equal amplitude of the cochlear microphonics as that produced by earphone stimulation. This method is based on the assumption that an equal amplitude of the cochlear microphonics means an equal stimulus effect. Furthermore, by observing the cochlear microphonics, it was ascertained that the cross hearing was negligible by using this method.
