Linear Compensators & Hearing Damage?

[Tomac]

Just out of idle curiosity, do linear compensators do anything at all for the shooter to reduce cumulative hearing damage? Thx!...
Tomac

[VIP3R 237]

They redirect the sound forward, but they do not reduce the DB's to safe levels for the shooter.

[Tomac]

They redirect the sound forward, but they do not reduce the DB's to safe levels for the shooter.

Understood, but does the reduced concussive effect also reduce cumulative hearing damage?
Tomac

[Captiva]

I am not an audiologist, but I cannot envision a definitive answer to this question.

I would think if you took identical twins with exactly the same hearing capacity and have one shoot 100 rounds of M193 out of a 9620 with an A2 versus the other twin shooting 100 rounds of M193 out of a 9620 with a BRT Covert Comp Flash Hider under identical circumstances then follow up with a hearing test might provide some scientific evidence.

In theory, and in general since the linear compensator directs the report more forward than an A2 flash hider one would think the impact to the shooters eardrum would be lessened.

But if you shoot an A2 outdoors and a linear comp indoors the opposite would likely occur.

[Ryno12]

It'll definitely suck less if you don't stand right in front of it.

[26 Inf]

Understood, but does the reduced concussive effect also reduce cumulative hearing damage?
Tomac

As you alluded, sound is pressure, it seems intuitive that in the open, with nothing to reverberate off of, db reading with a linear compensator should be lessened.

There are free decibel apps for smartphones, not sure how accurate they are, but even if the accuracy isn't perfect if would seem to be me that if you placed the phone near the shooter shooting a linear comp, and then repeated the experiment standing in the same position using a rifle with the same length barrel and an A2 compensator it should tell you if your getting substantial difference.

An increase of 10db effectively doubles the sound pressure level.

[JoshNC]

I am not an audiologist, but I cannot envision a definitive answer to this question.

I would think if you took identical twins with exactly the same hearing capacity and have one shoot 100 rounds of M193 out of a 9620 with an A2 versus the other twin shooting 100 rounds of M193 out of a 9620 with a BRT Covert Comp Flash Hider under identical circumstances then follow up with a hearing test might provide some scientific evidence.

In theory, and in general since the linear compensator directs the report more forward than an A2 flash hider one would think the impact to the shooters eardrum would be lessened.

But if you shoot an A2 outdoors and a linear comp indoors the opposite would likely occur.

It is all about the amount of noise (dB) at the individual's ears. Since the linear compensator does not reduce the report to hearing safe levels, any exposure will risk hearing damage.

Per OSHA guidelines, one can safely have the following duration of exposure to the following noise levels:
85 dB - 8 hrs
88 dB - 4 hrs
91 dB - 2 hrs
94 dB - 1 hr
97 dB - 30 min
100 dB - 15 min
103 dB - 7.5 min
106 dB - < 4 min
109 dB - < 2 min
112 dB - < 1 min
115 dB - < 30 sec

[26 Inf]

It is all about the amount of noise (dB) at the individual's ears. Since the linear compensator does not reduce the report to hearing safe levels, any exposure will risk hearing damage.

Per OSHA guidelines, one can safely have the following duration of exposure to the following noise levels:
85 dB - 8 hrs
88 dB - 4 hrs
91 dB - 2 hrs
94 dB - 1 hr
97 dB - 30 min
100 dB - 15 min
103 dB - 7.5 min
106 dB - < 4 min
109 dB - < 2 min
112 dB - < 1 min
115 dB - < 30 sec

85db is the threshold wear hearing protection for construction workers - ANSI - A10.46-2007, Hearing Loss Prevention in Construction and Demolition Workers. Applies to all construction and demolition workers with potential noise exposures (continuous, intermittent and impulse) of 85 dBA and above.

Gunfire Sound Levels

Gunfire Noise Level Reference Chart

Below we have listed critical data describing peak sound pressure levels produced by firearms used in shooting and hunting sports. A serious byproduct of this exposure is sensory-neural hearing loss, which cannot be restored to normal. With the introduction of MUZZLE BRAKES and PORTING, the risks of hearing loss dramatically increase. Use this chart as a reference guide for promoting the need of using adequate hearing protection.

Keep in mind that conversational speech is approximately 60-65 dB, and the threshold of pain is considered to be 140 dB. According to Dr. William Clark, Ph.D. senior research scientist in charge of the NOISE LABORATORY at the Central Institute for the Deaf in St. Louis, the damage caused by one shot from a .357 magnum pistol, which can expose a shooter to 165 dB for 2msec, is equivalent to over 40 hours in a noisy workplace. Dr. Krammer, Ph.D., Ball State University, Muncie, Indiana has documented the following pressure levels.

Table 1. SHOTGUN NOISE DATA (DECIBEL AVERAGES)

.410 Bore 28" barrel 150dB
26" barrel 150.25dB
18 _" barrel 156.30dB
20 Gauge 28" barrel 152.50dB
22" barrel 154.75dB
12 Gauge 28" barrel 151.50dB
26" barrel 156.10dB
18 _" barrel 161.50dB

Dr. Krammer continues to say that shotgun noise averaged slightly more that 150dB. This is approximately 14dB beyond the threshold of pain, and more than sufficient to cause sudden hearing loss with complications.

Table 2. CENTERFIRE RIFLE DATA

.223, 55GR. Commercial load 18 _" barrel 155.5dB
.243 in 22" barrel 155.9dB
.30-30 in 20" barrel 156.0dB
7mm Magnum in 20" barrel 157.5dB
.308 in 24" barrel 156.2dB
.30-06 in 24" barrel 158.5dB
.30-06 in 18 _" barrel 163.2dB
.375 — 18" barrel with muzzle brake 170 dB

Krammer adds that sound pressure levels for the various pistols and ammunition tested yielded an average mean of 157.5 dB, which is greater than those previously shown for shotgun and rifle noise levels. There was also a greater range, from 152.4dB to 164.5dB, representing 12 dB difference, or more than 10 time as much acoustic energy for the top end of the pistol spectrum. It should be noticed that this figure of 164.5 dB approaches the practical limit of impulse noise measurement capability inherent in most modern sound level meters.

Table 3. CENTERFIRE PISTOL DATA

.25 ACP 155.0 dB
.32 LONG 152.4 dB
.32 ACP 153.5 dB
.380 157.7 dB
9mm 159.8 dB
.38 S&W 153.5 dB
.38 Spl 156.3 dB
.357 Magnum 164.3 dB
.41 Magnum 163.2 dB
.44 Spl 155.9 dB
.45 ACP 157.0 dB
.45 COLT 154.7 dB

The above averages are for all types of ammunition used in these firearms, and should be considered fairly representative. No wonder we hear numerous reports about hearing loss as a result of firearms including acoustic traumas that take hearing completely as a result of one shot. Imagine what the noise levels must be when we incorporate muzzle brakes or porting into firearms, or have a gun explode near the ear due to malfunction.

OUR WARNING IS SIMPLE AND IS IN THE BEST INTERESTS OF EACH SHOOTER. AS THE SOUND PRESSURES INCREASE, SO DOES THE RISK OF PERMANENT HEARING LOSS. IF YOU INCORPORATE A PROCEDURE INTO YOUR SHOOTING THAT INCREASES THE SOUND LEVEL, YOU ALSO INCREASE THE RISK OF HEARING LOSS TO YOURSELF AND POSSIBLY THOSE WHO STAND NEAR YOU. BE SURE TO USE ADEQUATE EAR PROTECTION WHEN USING A FIREARM AND BE CAREFUL OF THOSE NEARBY. LAWSUITS HAVE ALREADY BEEN RECOGNIZED FOR GUNFIRE NOISE THAT HAS RESULTED IN HEARING LOSS. ALWAYS CONSULT A PROFESSIONAL AUDIOLOGIST, OTOLOGIST, OR OTOLARYNGOLOGIST WITH YOUR HEARING PROBLEMS. Hearing loss is not fun and can be prevented.

Compliments of www.earinc.com

[Chatterbox]

Considering that even silenced rifles produce in excess of 130 dB, I don't see the linear compensator doing anything to mitigate hearing loss.

[Junkie]

If it reduces the noise level at your ear, it mitigates hearing loss. It doesn't eliminate it though.

I don't know how much the noise level drops at your ear by using a linear comp rather than some other type of muzzle device. I'm a little surprised at some of the numbers provided above, but most of them make sense.