What to Know About Firearm Suppressors and Hearing Loss Does a firearm suppressor always do enough to protect hearing? No. Should firearm users also wear hearing protection? Yes. All Ears on Audiology
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All Ears on Audiology  |   March 01, 2018
What to Know About Firearm Suppressors and Hearing Loss
Author Notes
  • Michael Stewart, PhD, CCC-A, is a professor of audiology at Central Michigan University. stewa1mg@cmich.edu
    Michael Stewart, PhD, CCC-A, is a professor of audiology at Central Michigan University. stewa1mg@cmich.edu×
Article Information
Hearing Disorders / All Ears on Audiology
All Ears on Audiology   |   March 01, 2018
What to Know About Firearm Suppressors and Hearing Loss
The ASHA Leader, March 2018, Vol. 23, 18-20. doi:10.1044/leader.AEA.23032018.18
The ASHA Leader, March 2018, Vol. 23, 18-20. doi:10.1044/leader.AEA.23032018.18
More than 29 million Americans enjoy participating in target practice, hunting and other shooting sports (see sources below).
Indeed, U.S. citizens own about 310 million firearms, and numbers of female and young firearm-users have grown significantly in recent years (see sources). Along with this growth should come increased attention to safety, including that of our hearing.
While shooting sports can certainly be enjoyable, unprotected exposure to high-intensity firearm noise can also put people at significant risk for noise-induced hearing loss (NIHL) and associated tinnitus. Attaching a suppressor to the end of the barrel can reduce damaging noise, but may not lower it to hearing-safe levels.
This means that to effectively protect their hearing, recreational firearm users should always wear proper hearing protection devices on their ears, even when firearms are equipped with suppressors.
The cost of noise exposure
Almost all firearms generate peak impulse noise levels that exceed the 140 decibel peak sound pressure level (dB peak SPL) exposure limit mandated by the Occupational Safety and Health Administration (see sources). Big-bore firearms can generate noise levels of more than 165 dB, and guns with short barrels (handguns) and firearms fitted with muzzle breaks can elevate peak SPLs even further (see sources).
Hearing loss may occur gradually due to repeated unprotected exposure to firearm noise, or suddenly due to acoustic trauma from even a single unprotected, high-intensity gunshot. The resulting hearing damage is often characterized by normal or near-normal hearing sensitivity at lower frequencies, with a precipitous drop into the severe range at higher frequencies.
Those affected hear low-frequency vowels for audibility, but miss higher-frequency consonant sounds necessary for clarity. The result is a complaint clinical audiologists hear all the time from patients with this type of hearing loss: “I hear fine, but people mumble.” Fitting amplification to these clients can be challenging, especially when high-frequency audiometric thresholds are severely impaired from extensive damage to outer and inner cells in the cochlea. Hearing aids with advanced technology that shifts frequencies from areas of degraded hearing to areas of better residual hearing may help remediate this type of hearing loss.

Recreational firearm users should always wear proper hearing protection with shooting activities, even when firearms are equipped with suppressors.

Hearing protection benefits
The most direct way to reduce the risk of firearm-related NIHL is to significantly attenuate the peak SPL reaching the ears. Using hearing protection devices (HPDs)—such as muffs and plugs—attaching a suppressor to the muzzle of the firearm, or using these tools in combination can provide protection from firearm noise.
HPDs reduce firearm noise to the ears, and suppressors reduce firearm noise at the source (gun muzzle). Although the amount of attenuation provided by a properly fitted HPD is approximately 30 dB, real-world attenuation can vary, depending on the physical fit (see sources).
Also, recreational firearm users do not consistently wear HPDs during target practice or, especially, during hunting activities (see sources). Suppressors installed on the muzzles of firearms can consistently provide approximately 25 dB of attenuation for 100 percent of the shots fired (see sources).

Using a firearm suppressor will reduce the risk of acquiring noise-induced hearing loss, but not eliminate it.

How effective are suppressors?
When someone fires a gun, a sudden release of gases propels the bullet out of the gun barrel and generates a high-level acoustic impulse sound. Using standard high-velocity (supersonic) ammunition can break the sound barrier and further increase the SPL.
Attaching a suppressor to the end of the gun barrel can reduce the noise level by coupling a can-like device that has a chamber with a large volume to the muzzle of the firearm. Additionally, a series of baffles in the chamber further act as a muffler to reduce the impulse noise level.
However, suppressors cannot reduce the noise caused by the supersonic flight of the projectile breaking the sound barrier once it leaves the barrel of the firearm. Recent studies of suppressors fitted to larger-caliber firearms found that a reduction in peak SPLs of approximately 25–30 dB typically occurs when using standard high-velocity ammunition (see sources).
For example, a suppressor can reduce firearm impulse of 165 dB peak SPL to approximately 140 dB, which is still quite audible and potentially hazardous to hearing. Firearm users can further reduce firearm noise by using subsonic velocity (less than 1120 feet/second) ammunition. However, subsonic ammunition has significantly less range and energy than supersonic ammunition and is generally more appropriate for short-range target practice. Different types of firearms and ammunition produce different sound levels at discharge, and suppressors may be more or less effective at suppressing sound levels.
There is no standardized measurement protocol to assess the effectiveness of a suppressor. This means manufacturers cannot assure firearm users that they can adequately protect their hearing solely by using a suppressor. To effectively protect hearing, recreational firearm users should always wear proper HPDs, even when firearms are equipped with suppressors.
Proper hearing protection could include devices with a lower noise-reduction rating (NRR) than conventional plugs or muffs, and non-linear or moderately attenuating high-fidelity HPDs. Non-linear HPDs let soft and moderate sounds pass while attenuating loud (intense) sounds. Moderately attenuating high-fidelity HPDs provide less attenuation and uniformly reduce sound across the entire frequency range.
Other options are electronic HPDs (muffs, BTEs [behind-the-ears] or custom ITEs [in-the-ears] devices) which provide mild gain amplification to enhance hearing, but attenuate intense firearm noise when the trigger is pulled. Thus, recreational firearm users can monitor noise while ensuring they protect their hearing when firing shots.
Bottom line: Using a firearm suppressor reduces the risk of acquiring NIHL, but does not eliminate it. Suppressors can significantly reduce the peak SPL of firearm noise, but the noise remaining may still be high-intensity, loud and potentially hazardous to hearing.
Could the Hearing Protection Act Boost Use of Suppressors?

People who purchase a suppressor for their gun must undergo an FBI background check and obtain a special federal license. Recent pending congressional legislation, the Hearing Protection Act, would make suppressors more readily available to law-abiding citizens by allowing purchase of these devices immediately after a same-day background check of a buyer, similar to the process for purchasing rifles or shotguns.

The Hearing Protection Act aims to ease restrictions on access to suppressor devices in hopes of a reduced NIHL risk. In a recent interview, Knox Williams, president of the American Suppressor Association, noted the importance of support for the bill by the medical and hearing conservation communities, since they “should have a vested interested in doing everything they can to promote safe practices that help protect hearing.”

Many hearing conservationists believe that if the act becomes law, it will provide a valuable hearing conservation tool by allowing recreational firearm users to significantly reduce hazardous noise at the source.

Sources
Families Afield. (2010). An initiative for the future of hunting. Available from www.familiesafield.org/pdf/FamiliesAfield_Report.pdf.
Families Afield. (2010). An initiative for the future of hunting. Available from www.familiesafield.org/pdf/FamiliesAfield_Report.pdf.×
Krouse, W. (2012). Gun control legislation: Congressional research service report for Congress RL32842. Available from www.fas.org/sgp/crs/misc/RL32842.pdf.
Krouse, W. (2012). Gun control legislation: Congressional research service report for Congress RL32842. Available from www.fas.org/sgp/crs/misc/RL32842.pdf.×
Lobarinas, E., Scott, R., Spankovich, C., & Le Prell, C. (2016). Differential effects of suppressors on hazardous sound pressure levels generated by AR-15 rifles: Considerations for recreational shooters, law enforcement, and the military. International Journal of Audiology, 55(1), S59–S71 [Article] [PubMed]
Lobarinas, E., Scott, R., Spankovich, C., & Le Prell, C. (2016). Differential effects of suppressors on hazardous sound pressure levels generated by AR-15 rifles: Considerations for recreational shooters, law enforcement, and the military. International Journal of Audiology, 55(1), S59–S71 [Article] [PubMed]×
Meinke, D., Murphy, W., Finan, D., Lankford, J., Flamme, G., Stewart, M., … Jerome, T. (2014). Auditory risk estimates for youth target shooting. International Journal of Audiology, 53(S1), S16–S25. [Article] [PubMed]
Meinke, D., Murphy, W., Finan, D., Lankford, J., Flamme, G., Stewart, M., … Jerome, T. (2014). Auditory risk estimates for youth target shooting. International Journal of Audiology, 53(S1), S16–S25. [Article] [PubMed]×
Murphy, W., Flamme, G., Campbell, A., Zechmann, E., Tasko, S., Lankford, J., … Stewart, M. (2018). The reduction of gunshot noise and auditory risk through the use of firearm suppressors. International Journal of Audiology, 56(12), 1–14.
Murphy, W., Flamme, G., Campbell, A., Zechmann, E., Tasko, S., Lankford, J., … Stewart, M. (2018). The reduction of gunshot noise and auditory risk through the use of firearm suppressors. International Journal of Audiology, 56(12), 1–14.×
National Shooting Sports Foundation. (2013). Target shooting in America. Available from https://issuu.com/nssfpublications/docs/nssf_target_shooting_in_america_rep.
National Shooting Sports Foundation. (2013). Target shooting in America. Available from https://issuu.com/nssfpublications/docs/nssf_target_shooting_in_america_rep.×
National Shooting Sports Foundation. (2015). Women gun owners. Available from https://www.nssf.org/new-women-gun-owners-nssf-report-available/.
National Shooting Sports Foundation. (2015). Women gun owners. Available from https://www.nssf.org/new-women-gun-owners-nssf-report-available/.×
Statista. (2018). Number of participants in target shooting in the United States from 2006 to 2015. Available from www.statista.com/statistics/191962/participants-in-target-shooting-in-the-us-since-2006.
Statista. (2018). Number of participants in target shooting in the United States from 2006 to 2015. Available from www.statista.com/statistics/191962/participants-in-target-shooting-in-the-us-since-2006.×
Stewart, M., Foley, L., Lehman, M., & Gerlach, A. (2011). Risks faced by recreational firearm users. Audiology Today, 23(2), 38–48.
Stewart, M., Foley, L., Lehman, M., & Gerlach, A. (2011). Risks faced by recreational firearm users. Audiology Today, 23(2), 38–48.×
Stewart, M., Meinke, D., Snyders, J., & Howerton, K. (2014). Shooting habits of youth recreational firearm users. International Journal of Audiology, 53, S26–S34. [Article] [PubMed]
Stewart, M., Meinke, D., Snyders, J., & Howerton, K. (2014). Shooting habits of youth recreational firearm users. International Journal of Audiology, 53, S26–S34. [Article] [PubMed]×
U.S. Department of the Interior, U.S. Fish and Wildlife Service, U.S. Department of Commerce, & U.S. Census Bureau. (2012). 2011 National survey of fishing, hunting, and wildlife-associated recreation. Available from https://www.census.gov/prod/2012pubs/fhw11-nat.pdf.
U.S. Department of the Interior, U.S. Fish and Wildlife Service, U.S. Department of Commerce, & U.S. Census Bureau. (2012). 2011 National survey of fishing, hunting, and wildlife-associated recreation. Available from https://www.census.gov/prod/2012pubs/fhw11-nat.pdf.×
U.S. Fish and Wildlife Service. (2017). 2016 National survey of fishing, hunting, and wildlife-associated recreation. Available from http://wsfrprograms.fws.gov/Subpages/NationalSurvey/nat_survey2016.pdf.
U.S. Fish and Wildlife Service. (2017). 2016 National survey of fishing, hunting, and wildlife-associated recreation. Available from http://wsfrprograms.fws.gov/Subpages/NationalSurvey/nat_survey2016.pdf.×
U.S. Occupational Safety and Health Administration. (1983). Occupational noise exposure; Hearing conservation amendment; Final rule (29 CFR 1910.95). Federal Register, 48(46), 9738–9785.
U.S. Occupational Safety and Health Administration. (1983). Occupational noise exposure; Hearing conservation amendment; Final rule (29 CFR 1910.95). Federal Register, 48(46), 9738–9785.×
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March 2018
Volume 23, Issue 3