The Effects of Earplugs and Earmuffs on Pitch Discrimination in Noise.

摘要

Earplugs and earmuffs are often not worn in hazardous noise because of workers' conviction that they do or at least may impair their perception of relatively slight acoustic cues important in trouble-shooting. A job sample was arranged of discrimination of a + 10% pitch change in an octave band of noise centered either at 500 to 2000 Hz. The signals were embedded in a typical submarine engineroom noise, at each of three S/N ratios. Judgments were made by four trained adults either in an unfiltered (i.e., open-ear) condition or through a multifilter circuit simulating the insertion loss either of a typical earplug or a typical earmuff. S/N was constant across each open-ear vs earplug vs earmuff comparison. Performance was of course degraded at more unfavorable S/N, and was always worse at 2000 Hz. Primarily, performance was always worse for the earplug than for the open-ear condition, and still worse (by up to 25%) for the earmuff condition. It is clear that for this particular job sample the wearing of plugs, and especially of muffs, does indeed distort the spectra cues upon which excellent performance depends.