Listening devices in auditoriums for listeners with perceptual problems

Abstract

Acoustic criteria for auditoriums have been developed for listeners with normal perceptual skills. In consequence, these criteria applied to room acoustics may not be good enough for listeners with perceptual deficiencies. Perceptual problems are usually associated with congenital or acquired hearing losses, but also, elderly listeners who might have only slightly less acute hearing then their younger counterparts find listening in some auditoriums very difficult. Three parameters contribute to such problems: sound pressure level too low, speech‐to‐noise ratio too low, and reverberation too long. When acoustic conditions become unsatisfactory, many listeners cease attending lectures, art performances, etc. In some communities loss of elderly listeners might consist of a significant reduction in public support of drama theaters or concerts. The so‐called “group amplification systems” or “listening devices” can provide help for listeners with perceptual problems. The main principle of such devices is to pick up the signal close to the source and deliver it directly to the listener's ears. In such a way the signal can be individually amplified and delivered without background noise and reverberation. The following systems which are presently in use will be discussed: (1) hard wired, (2) induction loop, (3) amplitude modulation, (4) frequency modulation, and (5) infrared. All these systems will be discussed for the use of listeners with and without hearing aids. [Work supported by NIH.]