Turning Down the Noise of Combat

By Col. John T. Dillard (U.S. Army, Ret.)

Modern warfare demands constant innovation and technological advancements to ensure military personnel are equipped with the most effective and safe tools for their missions. A significant aspect of this is hearing protection, given the prevalence of loud noises from firearms, explosives, and other high-impact weapons on the battlefield. 

And noise is the main contributor to the returning veteran’s top health complaint: hearing loss and often, tinnitus, or ringing in the ears—permanent conditions that have no cure and can only be managed. 

John Dillard on the far left with his “Band of Brothers” from the 2nd Battalion, 504th Parachute Infantry Regiment, 82nd Airborne Division, in the Sinai Desert in 1981.

The need for hearing protection has led to the development of helmet modifications (see “Hearing Protection” below), now employing electronic earcups, trading a bit of ballistic protection over the ears for hearing protection. It’s important for ground troops to be able to hear “the snap of the twig” via amplification, as well as automatically attenuating loud noises above harmful decibel levels—both features being provided by the earcups.

Sound Suppression

As a secondary measure, sound suppression technology is the latest innovation in military weapons. These recent advancements are detailed in the article “What's the Firepower Like for the Army's New Rifle Automatic Rifle?” from Army Times. The U.S. fighting force will now have “silencers”—actually sound and signature suppressors on its array of future small arms.

As mentioned, the welfare of military personnel, including their auditory health, is a matter of paramount importance. The harsh, high-decibel noises encountered during combat operations lead to hearing damage, tinnitus, and other long-lasting auditory impairments like difficulty hearing speech in noise and other auditory processing disorders. Operationally, however, impaired hearing during close combat compromises communications and situational awareness, thus jeopardizing the lives of service members in the field.

More accurately termed blast suppressors, silencers function by redirecting and dissipating the energy produced by projectiles fired from pistols, rifles, and machine guns by a series of baffles within a tube-shaped “can.” 

President Theodore Roosevelt was perhaps the most famous user of sound suppression on his firearms for his big game hunting exploits. But while they have existed for over 100 years, they have only recently been perfected to require less maintenance and can actually improve accuracy. 

Modern suppressors also provide tactical advantage by concealing the shooter's position on the battlefield by reducing the sound signature of the gunshot. The gunshot is quieter and more muffled. To date, 32 states in the U.S. allow purchasing of suppressors today, if the buyer passes the background check and is registered.

How much noise reduction is possible? Well, in no way do suppressors negate the need for hearing protection. The Hollywood “puff” that we see in movies is not an accurate depiction of reality at all. Depending upon cartridge caliber, ambient atmospheric conditions, and other factors, the average gunshot is around 165 to 185 decibels.

Any noise above 140 dB can cause instant and irreversible hearing damage. By comparison, the average police car siren can be 120 dB—permanently damaging unprotected ears in mere seconds. Jackhammers and rock concerts can also reach levels of 120 dB.

Modern suppressors can only achieve a reduction of 25 to 35 dB. But remember also that the decibel scale is logarithmic, so each bit of reduction is significant. Every 3 dB increase doubles the sound intensity and doubles the risk to hearing. But every 3 dB reduction cuts this in half.

Remember, too, that hearing damage can result from a single loud event, or it can occur as a result of exposure to loud sounds over time. “Noise above 70 dB over a prolonged period of time may start to damage your hearing,” says the Centers for Disease Control and Prevention.

Hearing Protection

Relatedly, the U.S. Department of Defense (DoD) will soon require hearing protection fit testing for service members to prevent hearing loss and maintain readiness in the field.

Fit testing measures the actual noise reduction level provided by an individual's hearing protection. This helps ensure they are adequately protected from hazardous noise levels.

According to a DoD report, "Fit testing can tell us the true attenuation an individual is getting from a hearing protector, rather than forcing us to rely on selecting a protector with much more noise reduction than is needed to obtain a wide margin of safety to protect listeners who have a relatively poor fit with the device," says Douglas Brungart, Ph.D., the chief scientist for the Audiology and Speech Center at Walter Reed National Military Medical Center in Maryland.

Individual fit testing will allow the selection of optimal hearing protection versus over-protection that can hinder communication and situational awareness.

And the U.S. Navy started testing a new hearing protection helmet for flight crew working in extremely loud environments, according to Navy Times.

The Navy Times story reports, “The HGU-99/P Hearing Protection Helmet aims to facilitate crew communication and curtail hearing loss by including additional hearing and impact protection, according to Amie Blade, a spokesperson for Naval Air Systems Command.”

In the ever-evolving landscape of military technology, all of these innovations will continue to play a pivotal role in mitigating auditory risks. This helps ensure the safety of those who serve in the armed forces, and enabling them to operate at their best, while preserving their vital auditory senses in the face of adversity.

Col. John T. Dillard (U.S. Army, Ret.) is the former chair of Hearing Health Foundation’s Board of Directors. He has written about his tinnitus in “What Works for Me” and “One Man’s Military Perspective” on our blog and in our magazine.

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