Hearing Safe Is a Number: How to Read Suppressor dB Claims

A suppressor spec sheet that says 'hearing safe' is quoting a threshold, a method and a microphone position. Each of those can change the answer.

What the label is really claiming

Suppressor marketing has a phrase for the quietest products: "hearing safe." It sounds like a certification. It is not one. No government agency stamps a suppressor with that phrase, and the term has no single legal definition. In practice, a manufacturer that uses it is saying that some tested combination of firearm, ammunition and suppressor produced a peak sound level beneath a threshold, usually about 140 decibels, when measured a particular way.

That sentence contains four variables: the combination, the threshold, the measurement and the word "peak." Change any one of them and the claim changes. This page walks through where the threshold comes from, why the other variables matter, and what a peak figure leaves out. It does not rank products, because the data to do that fairly do not exist in a comparable form.

As of October 2026, the sources below are the primary documents; if you are reading this much later, check that they have not been revised.

Where 140 dB comes from

Three separate bodies use a 140 dB peak figure for impulsive noise, and a gunshot is the textbook example of impulsive noise.

• OSHA. The occupational noise standard at 29 CFR 1910.95 says exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level. The same standard sets an 8-hour time-weighted average of 85 decibels as its action level, and its permissible exposure table starts at 90 dBA for eight hours.
• NIOSH. The 1998 revised criteria document recommends an exposure limit of 85 dBA as an 8-hour time-weighted average, using a 3-decibel exchange rate, and discusses 140 dB peak sound pressure level as the generally accepted ceiling limit for impulsive noise.
• The Department of Defense. MIL-STD-1474E, the military's noise-limits design standard, sets a requirement for impulsive noise of peak levels below 140 dBP at the ear, whether protected or unprotected, and it treats sources at or above 140 dBP under a separate appendix that describes a model-based method called AHAAH and a unit called the auditory risk unit.

These are occupational and military standards, designed for workplaces and equipment programs. They are not rules for a weekend at the range. They are, however, where the "140" in a marketing sheet comes from, and reading them tells you what the number does and does not describe.

Peak is one number among several

Sound exposure has more than one dimension, and the standards above use several.

A suppressor claim is nearly always a peak claim. A shooting session is an exposure made of many shots. A number that is fine for one shot does not tell you about fifty.

A quick note on decibel arithmetic

Decibels are logarithmic. Every 3 dB increase represents roughly a doubling of sound energy, which is why a 3-dB exchange rate makes sense: if the level goes up 3 dB, the safe time is cut in half. A common rule of thumb says a 10 dB increase is heard as roughly twice as loud, though that is a perceptual approximation rather than a measurement. The practical consequence is that a few decibels of difference between two suppressors are not trivially small, and a claim of "2 dB quieter" is much less meaningful than it sounds without the measurement context.

Why measurement position changes the answer

MIL-STD-1474E specifies equipment and procedure for measuring weapons noise. It requires specific microphone types and recording rates, a free-field test arrangement with no reflecting surfaces other than the ground within about 30 meters, multiple impulses per condition, and, for personnel exposure, a microphone placed 15 centimeters from the ear exposed to the highest level.

Now compare that with the CDC/NIOSH suppressor study by Murphy and colleagues, published in the International Journal of Audiology in 2018. It measured suppressed and unsuppressed firearms with both high- and low-velocity ammunition, using microphones at several locations, including near the muzzle, at the left and right ear positions and at an instructor position behind the shooter. Their results illustrate the point. In one example from the paper, a .308 rifle with high-velocity ammunition measured 161 dB peak unsuppressed and 137 dB suppressed at the left ear. The same paper reports that suppressors reduced peak levels at the ears by roughly 17 to 24 dB in its summary.

Two lessons follow. First, a suppressor can bring a very loud firearm down by a large amount. Second, a figure measured at one position is not interchangeable with a figure measured at another. When a spec sheet gives a number without a microphone position, it is incomplete.

What a below-140 reading leaves out

Even a trustworthy peak number below 140 dB leaves out several things:

• Cumulative exposure. The study's authors write that cumulative exposures from suppressed firearms can still present a significant hearing risk, and they say hearing protection should be worn whenever firing a gun. They also note that peak reductions may overstate the benefit compared with reductions in an energy-based average.
• Environment. Indoor ranges, covered firing lines and nearby walls reflect sound. Free-field test conditions do not.
• Other shooters. The nearest gun is not always yours.
• Ammunition and barrel length. A measurement applies to the ammunition and barrel in the test. Supersonic bullets add their own crack, which a suppressor does not remove. Our guide to subsonic ammo by caliber explains why.
• Individual sensitivity and existing hearing loss. Standards describe populations, not you.

A reader's checklist for any dB claim

When a product page or a review quotes a number, ask:

1. Which metric? Peak, A-weighted average or something else?
2. Which standard or method? Is MIL-STD-1474 cited, and which edition? Was the test run to a published protocol?
3. Where was the microphone? Near the muzzle, at the shooter's ear, or somewhere else?
4. Which ammunition and barrel length? Was it the load you will shoot?
5. How many shots, and was the number an average or a best case?
6. Who measured it? An independent lab, the manufacturer or a reviewer with a phone app? Our post on sound ratings explained covers why informal recordings are weak evidence.
7. Was the suppressor new, clean and in the same configuration you will use?

If a page cannot answer most of these, treat the figure as marketing rather than measurement.

What to do with this

The standards above are a reason to take hearing protection seriously, not a green light to skip it. A suppressed rifle can still produce levels that matter, and a suppressed pistol has mechanical noise that no can removes. Our long-standing piece, A Suppressor Is Not Hearing Protection, makes the same argument from the myth side, and Quieter Does Not Mean Quiet looks at fatigue over a day. For the rating on the earmuffs or plugs themselves, BuyMoreGuns explains NRR, derating and doubling up.

Hearing questions beyond general information belong with an audiologist or occupational health professional.

What this page does not claim

We have not measured any suppressor, and we are not ranking any product's sound output. The facts above come from the cited documents, and we recommend reading them rather than relying on our summary. Standards get revised: MIL-STD-1474E supersedes the 1997 edition, and OSHA and NIOSH both update their guidance from time to time. This page is scheduled for review by April 12, 2027.

Bottom line

"Hearing safe" is a threshold, a method and a microphone position wearing a friendly label. Read it as a claim about one peak measurement, check what is behind it, and keep hearing protection on regardless.