AuditionResearch in audition, as well as in other fields in which sound is a relevant factor, employs apparatus for the production, control, and analysis of tones. The most significant classes of sound devices are sound generators, amplifiers, and instruments for measuring frequency, intensity, and composition of sounds. The most common tone generator is the audio oscillator. Electronic audio amplifiers permit magnification; and wave analyzers, oscillographs, and voltmeters provide appropriate measurements. Apparatus for the recording and reproduction of sound finds application in nearly every phase of psychological investigation.
BASIC DEFINITIONS AND ACOUSTICAL UNITS
THE NATURE OF SOUNDBefore consideration is given to specific apparatus for the production, recording, and measurement of sound, it is desirable to turn briefly to concepts and definitions in the field of acoustics. The term sound is employed to refer to vibrational energy transmitted in air or other elastic media. The propagation of the energy occurs by means of progressive longitud inal vibratory disturbances in the transmitting medium. The term is also used to designate the sensation produced in the ear by these physical disturbances.The longitudinal waves which give rise to the sensation of sound are produced by objects in vibration; and a material substance is necessary for their transmission to the auditory sense organ. The most common transmission medium is, of course,