Measuring recreational firearm noise.

Abstract

Recreational use of firearms in the United States is commonplace. There are 28 × 106 Americans who consider themselves hunters and 13 × 106 went hunting in 2000. Participation in the shooting sports, without the use of properly worn hearing protection, exposes the involved persons to high levels of impulsive noise which may cause hearing loss and/or tinnitus (ear ringing). The present study was initiated to gain a better understanding of the noise exposure created by contemporary firearms using state of the art instrumentation and to ultimately increase our knowledge and awareness of this unique noise hazard. The sound pressure signal created by recreational firearms as used in hunting or target practice is characterized by a high-frequency, short duration impulsive noise. This signal is perceived by the human ear as one single, loud impulse or “shot.” However, when the firearm sound level is measured with microphones capable of sampling wide frequency ranges and combined with high-speed data acquisition computer systems, the impulses can be resolved into a number of different acoustic signals related to different source mechanisms.

Measurement of impulse peak insertion loss for four hearing protection devices in field conditions

“…The measurements confirm the results for impulse levels that bystanders might experience (Rasmussen et al, 2009). At 0.92 metres to the side of the muzzle, the peak levels were about 170 dB, 2.2 metres back and 1.5 metres to the right of the muzzle yielded 150 dB peak levels.…”

Shooting habits of youth recreational firearm users

“…Firearm noise exposure causes audiometric confi gurations frequently characterized by normal or near normal hearing in the lower frequencies, with a precipitous high frequency sensorineural hearing loss bilaterally. The left ear (gun blast ear) is often worse than the right ear because it is closer to the muzzle of a rifl e or shotgun and the right ear is also partially protected by a head baffl e for right-handed shooters (Rasmussen, et al, 2009). In addition to hearing loss, tinnitus may also result after fi rearm noise exposure (Smith et al, 2000;Niskar et al, 2001;Olsen-Widen & Erlandsson, 2004).…”

Auditory risk of air rifles

“…We elected to use 1/2″-inch microphones instead of the more conventional microphones in order to maximize signal-to-noise ratio. Microphones of this size require a compromise between avoiding diffraction effects that would result from having the microphone pointed toward the direction of propagation (i.e., normal incidence of the diaphragm to the sound source) and the signal cancellation effects associated with narrow wavefronts traveling across the diaphragm surface if the diaphragm is oriented at grazing incidence to the sound source (see Rasmussen, et al, 2009 for more information). We utilized grazing incidence in the current study, realizing that this could result in attenuation of peak amplitudes if the air rifles produced a very narrow wavefront.…”