Sage Journals: Discover world-class research

Abstract

Signal detection thresholds to a vehicle backup alarm were determined for audiometrically-normal subjects under broadband (pink) noise at 75, 85, and 95 dBA. The objective was to compare detection performance achieved under two contemporary amplitude-sensitive hearing protection devices (HPDs), an electronic Peltor T7-SR earmuff and a passive, orifice-type E-A-R Ultra 9000 earmuff, against detection achieved under the conventional (non-amplitude-sensitive) counterparts to these muffs, a Peltor H7A and an E-A-R 2000. Amplitude-sensitive HPDs are intended to provide better hearing in low noise levels either through band-limited amplification of outside sounds (electronic Peltor muff), or through reduced attenuation via passage of low-intensity sounds (E-A-R 9000). However, for the noise conditions and common warning signal tested, the amplitude-sensitive HPDs produced no statistically-significant advantage in masked signal threshold compared to the conventional muffs. Therefore, it cannot be concluded that these amplitude-sensitive muffs will improve aural detection of important workplace sounds of similar frequency content to the backup alarm evaluated herein. A separate analysis comparing the dBA levels experienced under the Peltor electronic muff with the circuit on and off indicated that the subjects’ gain control setting did not significantly increase the noise exposure dose over amplifier-off conditions.

Get full access to this article

View all access options for this article.

References

Abel

S. M.

Krever

E. M.

Giguere

Alberti

P. W.

(1991). Signal detection and speech perception with level-dependent hearing protectors. Journal of Otolaryngology, 20(1), 46–53.

Acton

W. I.

(1967). Effects of ear protection on communication. Annals of Occupational Hygiene, 10, 423–429.

Berger

E. H.

(1991). Flat-response, moderate-attenuation, and level-dependent HPDs: How they work, and what they can do for you. Presented at the 16th Annual Conference of the National Hearing Conservation Association, San Antonio, TX.

Casali

J. G.

(1994). A classification of special hearing protectors designed to improve auditory perception. Paper from Congress Distinguished Lecture in Proceedings of the Brazil/Argentina Congress in Acoustics and Vibration, Florianopolis, Santa Catarina, Brazil, 24–46.

Casali

J. G.

Grenell

J. F.

(1990). Noise-attenuating earmuff comfort: A brief review and investigation of band-force, cushion, and wearing-time effects. Applied Acoustics, 29, 117–138.

ISO (1986). Danger signals for work places – auditory danger signals, ISO 7731–1986(E). Geneva: International Organization for Standardization.

Morrill

J. C.

(1984). Audiometric instrumentation: Equipment choices, techniques. Occupational Health and Safety, 53 (10), 78–84.

OSHA (1981). Occupational noise exposure: Hearing conservation amendment. Occupational Safety and Health Administration. 46(11), pp. 4078–4181. Washington D.C.: Federal Register.

OSHA (1983), 29CFR1910.95. Occupational noise exposure; Hearing conservation amendment; Final rule. Occupational Safety and Health Administration. Code of Federal Regulations, Title 29, Chapter XVII, Part 1910, Subpart G, 48 FR 9776-9785. Washington, DC: Federal Register.

10.

Robinson

G. S.

Casali

J. G.

(in press). Audibility of reverse alarms under hearing protectors for normal and hearing-impaired listeners. Ergonomics.

11.

SAE (1978). Performance, test, and application criteria for electronically operated backup alarm devices. ANSI/SAE J994b–1978. Warrendale, PA: Society of Automotive Engineers, Inc.

12.

Suter

A. H.

(1989). The effects of hearing protectors on speech communication and the perception of warning signals (AMCMS Code 611102.74A0011). Aberdeen Proving Ground, MD: U.S. Army Human Engineering Laboratory.

13.

Wilde

Humes

L. E.

(1990). Application of the articulation index to the speech recognition of normal and hearing-impaired listeners wearing hearing protection. Journal of the Acoustical Society of America, 87(3), 1192–1199.

14.

Wilkins

P. A.

Martin

A. M.

(1977). The effect of hearing protectors on the masked thresholds of acoustic warning signals. Proceedings of the 9th International Congress on Acoustics (pp. H77-1 to H77-5).

Do Amplitude-Sensitive Hearing Protectors Improve Detectability of Vehicle Backup Alarms in Noise?

Abstract

Get full access to this article

References