Human ears are most sensitive to frequencies between roughly 2,000 and 5,000 Hz, which is part of the reason sounds in that range can become painful at lower volumes than very deep bass or very high-pitched tones. As for loudness, sustained exposure above about 85 decibels (dB) can gradually damage hearing, while sounds above 120 to 140 dB cross into the territory of immediate physical pain. But those two numbers highlight something important that most people miss: the threshold where your ears start being permanently injured is far below the threshold where you actually feel pain.
Why Certain Frequencies Hurt More
Your ear canal is essentially a tube, and like any tube, it has a natural resonance. In adults, that resonance falls somewhere around 2,500 to 3,000 Hz, which means the canal physically amplifies sounds in that frequency band by several decibels before they even reach the eardrum. This is why a high-pitched squeal at 3,000 Hz feels far more piercing than a low rumble at 200 Hz played at the same measured volume. The ear canal, the concha (the bowl-shaped part of your outer ear), and the middle-ear bones all conspire to boost mid-to-high frequencies, because that range matters most for understanding speech. The trade-off is that those same frequencies can hurt and damage more easily.
Interestingly, this resonance frequency shifts with age and anatomy. In infants, the ear canal is shorter, pushing the resonance peak higher. Research on infant ears shows the ear-canal resonance starts around 4,400 Hz at one month of age and gradually drops to about 2,900 Hz by two years old as the canal grows longer.1PubMed Central. Pressure transfer function and absorption cross section from the diffuse field to the human infant ear canal This means a young baby’s ear amplifies a slightly different band of frequencies than an adult’s, and sounds that seem tolerable to you might be disproportionately loud for a small child.
At the opposite end, very low frequencies (below about 20 Hz, sometimes called infrasound) and very high frequencies (above roughly 20,000 Hz, called ultrasound) generally fall outside conscious hearing. But that does not make them harmless. Infrasound at high intensity can stimulate the vestibular system, the balance organs in your inner ear, even when you don’t hear the sound as a tone. One study found that exposure to infrasound increased body sway in subjects whether or not they perceived any audible sensation.2Journal of Low Frequency Noise, Vibration and Active Control. Effects of Infrasound on Human Body Sway People exposed to strong infrasound sometimes report dizziness, pressure in the ears, or a sense of unease even though they can’t point to a “sound” they’re hearing.
Ultrasound and the Myth of Inaudibility
Ultrasound is worth its own mention because many people assume that if a frequency is above human hearing range, it can’t cause harm. That’s wrong at high enough intensities. Research on occupational ultrasound exposure found that eight hours of exposure at 110 dB at 20 kHz did not damage hearing in the audible range. But ramp that up to 150 dB at 20 kHz for just 15 minutes, and audible-frequency hearing loss did occur.3MDPI. Possible Effects on Health of Ultrasound Exposure, Risk Factors in the Work Environment and Occupational Safety The gap between “safe” and “damaging” is enormous in terms of intensity, but the point stands: ultrasound at extreme levels can hurt the structures of the inner ear even though you wouldn’t call the sensation “hearing a sound.”
When Volume Becomes Dangerous
Most regulatory guidelines converge on about 85 dB as the threshold where prolonged exposure starts putting your hearing at risk. The U.S. National Institute for Occupational Safety and Health (NIOSH) recommends an exposure limit of 85 dB averaged over an eight-hour workday, using what’s called a 3-dB exchange rate: every 3-dB increase in noise level cuts the safe exposure time in half.4The Journal of the Acoustical Society of America. Revisiting the NIOSH Criteria for a Recommended Standard: Occupational Noise Exposure So at 88 dB, you have about four hours. At 91 dB, two hours. At 100 dB, roughly fifteen minutes. At a rock concert pushing 110 dB, the safe window shrinks to under two minutes.
The pain threshold sits considerably higher, generally between 120 and 140 dB depending on the person and the frequency. That gap matters enormously. You can be well below the level that feels painful and still accumulate permanent hearing damage if the exposure goes on long enough. This is the trap most people fall into: if it doesn’t hurt, they assume it’s safe. The science says otherwise.
What Actually Happens Inside Your Ear
When sound enters the cochlea, the spiral-shaped organ deep in your inner ear, vibrations are converted into electrical signals by tiny sensory cells called hair cells. There are two types: outer hair cells, which amplify quiet sounds and sharpen frequency discrimination, and inner hair cells, which send signals to the auditory nerve for the brain to interpret. Intense noise hits the outer hair cells first and hardest. After acoustic trauma, these cells lose their structural integrity and begin a self-destruction process driven by oxidative stress, essentially an overload of damaging molecules.5PubMed Central. Inner Ear Hair Cell Protection in Mammals against the Noise-Induced Cochlear Damage Once outer hair cells die, mammals cannot regenerate them. The loss is permanent.
The classic signature of noise-induced hearing loss is a dip in hearing sensitivity around 4,000 Hz on an audiogram, often called a “4 kHz notch.” This happens because the geometry of the cochlea places the region most vulnerable to mechanical stress right where 3,000 to 6,000 Hz signals are processed. The ear canal’s resonance boost in that same range makes matters worse: the inner ear receives more energy at those frequencies than the external sound level alone would suggest.
Hidden Hearing Loss
One of the more unsettling discoveries of the past decade is that damage can occur even when standard hearing tests come back normal. Animal studies have shown that noise exposure that doesn’t cause a permanent shift on an audiogram can still destroy the synaptic connections between inner hair cells and the nerve fibers that carry signals to the brain.6PubMed Central. Cochlear Synaptopathy and Noise-Induced Hidden Hearing Loss This condition, called cochlear synaptopathy, means you can still detect quiet tones in a sound booth but struggle to follow conversation in a noisy restaurant. Your audiogram looks fine. Your real-world hearing doesn’t.
The process is insidious because it affects the nerve fibers that respond to moderate and loud sounds, which are exactly the fibers you need for picking out speech against background noise. Research suggests this synaptic damage can begin well before any obvious hearing loss appears on clinical tests.7PubMed Central. Cochlear synaptopathy in acquired sensorineural hearing loss: Manifestations and mechanisms The implication is sobering: by the time a standard test picks up a problem, significant underlying damage may have been accumulating for years.
Impulse Noise Is a Different Beast
Not all dangerous sound is steady. A gunshot, an explosion, a hammer blow on metal — these produce impulse noise, an extremely short burst at very high intensity. The ear has a built-in protective mechanism called the stapedius reflex: a small muscle in the middle ear contracts in response to loud sound, stiffening the chain of tiny bones and reducing the energy transmitted to the cochlea. This reflex offers some protection against ongoing low-frequency noise at moderate levels.8PubMed. Acoustic stapedius reflex function in man revisited But the reflex takes tens of milliseconds to kick in, which is far too slow to catch a gunshot that peaks in under a millisecond.
Research comparing continuous and impulse noise shows that the damage patterns inside the ear differ. Continuous noise tends to cause the gradual outer-hair-cell destruction described above, while impulse noise can tear structures mechanically in a way continuous sound at the same average energy does not. The acoustic reflex that partially shields the cochlea from steady noise simply cannot activate fast enough for a sudden blast.9PubMed Central. Noise-induced Hearing Loss: Continuous versus Impact/impulse Noise This is why a single unprotected gunshot can cause more immediate harm than hours at a moderately loud factory.
Tinnitus and Hyperacusis
Ringing in the ears, known as tinnitus, is one of the most common consequences of noise exposure. It’s not a sound coming from outside; it’s generated internally by a brain that has lost some of its normal input and is, in a sense, turning up the volume on its own circuitry. When cochlear damage reduces the signal reaching the central auditory system, the brain compensates by boosting neural activity at higher levels of the auditory pathway. This compensatory amplification is thought to underlie both tinnitus and hyperacusis, a condition where ordinary sounds become uncomfortably or even painfully loud.10PubMed Central. Central gain control in tinnitus and hyperacusis
Tinnitus specifically appears to involve neuroplastic changes at multiple levels of the auditory pathway, from the synapses between inner hair cells and the auditory nerve all the way up to the auditory cortex.11PubMed Central. Underlying mechanisms of tinnitus: review and clinical implications Hyperacusis may reflect a related but distinct process. One model proposes that additive neural “noise” compensating for hearing loss generates tinnitus, while a multiplicative gain increase compensating for hidden synaptic damage generates hyperacusis.12PubMed Central. Tinnitus and hyperacusis: Central noise, gain and variance In practical terms, people with hyperacusis can experience genuine pain from sounds that everyone around them considers perfectly normal, like dishes clinking or a car door closing.
Recent animal research has confirmed that sound-evoked pain is a real physiological phenomenon, not just psychological distress. Mice exposed to high-intensity sound showed measurable pain behaviors, including facial grimacing, that exceeded the thresholds seen in established pain models. These responses were absent in mice lacking functional sound transduction in the cochlea, confirming the pain originates through the auditory pathway.13eNeuro. Machine Learning-Guided Video Analysis Identifies Sound-Evoked Pain-Related Behaviors from Facial Grimace and Body Cues in Mice For humans with severe hyperacusis, this research validates what patients have long reported: sounds that seem ordinary to others really do cause them physical pain.
Headphones and Everyday Listening Risks
Most people’s cumulative noise exposure comes not from industrial settings but from recreational listening. A large Australian study of personal listening device use found that about 15 percent of users listened at levels and durations classified as posing a potential risk to hearing, with younger people significantly overrepresented in the higher-risk categories.14PubMed Central. Personal Listening Devices in Australia: Patterns of Use and Levels of Risk The study noted that while headphone use alone wasn’t putting the majority of users in danger, it could push people whose total daily noise exposure from commuting, work, and social settings was already borderline over the edge into unsafe territory.
The practical takeaway is that your headphones are not uniquely dangerous, but they add to everything else your ears absorb in a day. If you work in a noisy office, commute on a loud subway, and then put in earbuds for two hours at high volume, the cumulative load matters more than any single source. A rough guideline many audiologists suggest: if someone standing an arm’s length away has to raise their voice for you to hear them over your headphones, the volume is too high.
Hearing Protection That Actually Works
Not all hearing protection performs equally across frequencies. Earplugs, the foam type you roll up and insert, tend to work better at higher frequencies but offer less attenuation at low frequencies. Earmuffs cover a broader range and outperform earplugs in the mid and high frequencies. Research comparing the two found that at frequencies above 1,000 Hz, earmuffs provided roughly 14 dB more protection than earplugs.15PubMed Central. The Efficiency of Hearing Protective Devices against Occupational Low Frequency Noise in Comparison to the New Subjective Suggested Method At lower frequencies, below about 160 Hz, neither type does a great job, which is one reason low-frequency industrial noise remains a persistent occupational health challenge.
For maximum protection in very loud environments, such as shooting ranges or around heavy machinery, wearing both earplugs and earmuffs together is standard advice. The combined attenuation isn’t simply the sum of both ratings, but it does add a meaningful margin. Custom-molded earplugs with flat-attenuation filters are popular among musicians because they reduce volume more evenly across frequencies without making music sound muffled, though they cost more and require fitting by an audiologist.
Treatment After Acute Acoustic Trauma
If you’ve just been exposed to an extremely loud event, like an unprotected gunshot or an explosion at close range, the window for medical intervention is narrow. Oral corticosteroids, specifically prednisolone, are the most studied treatment. A comparison of different dosing regimens for acute acoustic trauma from gunshot noise found that a higher dose of prednisolone (60 mg per day for 10 days, then tapered over four more days) produced better hearing recovery than lower-dose protocols.16PubMed. Comparison of oral steroid regimens for acute acoustic trauma caused by gunshot noise exposure Steroids work by reducing inflammation and may help limit the oxidative damage cascade in the cochlea if started quickly enough, ideally within the first 24 to 72 hours.
Beyond steroids, no drug is currently approved specifically for noise-induced hearing loss, though several otoprotective compounds are in clinical trials. Some target the oxidative stress pathway, attempting to neutralize the damaging molecules that accumulate after noise exposure. Others aim to protect or regenerate the synaptic connections lost in hidden hearing loss. None are available outside of research settings as of now, which means prevention remains far more effective than any treatment. The hair cells you protect today are the only ones you’ll ever have.
Who Is More Vulnerable
Individual susceptibility to noise damage varies more than most people realize. Genetics play a role: some people carry gene variants that make their hair cells more resilient to oxidative stress, while others are predisposed to faster deterioration. Smoking constricts blood flow to the cochlea, and the inner ear’s oxygen supply is already tenuous under normal conditions. Certain medications, particularly aminoglycoside antibiotics and some chemotherapy drugs, are directly toxic to hair cells and can dramatically lower the threshold at which noise causes damage. If you’re taking one of these drugs and are also exposed to loud environments, the combined effect can be worse than either alone.
Age matters in both directions. Children’s smaller ear canals shift the resonance peak higher, as noted earlier, meaning they may receive more amplification at different frequencies than adults. Older adults face a double burden: age-related hearing loss (presbycusis) is already reducing their hair cell population, so each additional noise insult causes proportionally greater functional loss. A 60-year-old who attends a loud concert unprotected may lose ground they’ll never recover, in a way that a 25-year-old with a full complement of healthy hair cells might partially bounce back from, at least on an audiogram. But that 25-year-old may still be accumulating hidden synaptic damage that won’t show up for decades.
The frequency question and the loudness question ultimately point to the same underlying reality: your ears are precision instruments operating in a world that is, acoustically, far rougher than they were designed for. The frequencies that hurt most are the ones your ear naturally amplifies, and the volume level that causes permanent damage is well below the level that feels painful. Treating hearing as a finite, non-renewable resource, rather than something that will simply endure whatever you throw at it, is the single most useful shift in thinking the science supports.