Is a sound level of 105 decibels for a few seconds enough to rupture a person's eardrum?
Is a sound level of 105 decibels for a few seconds enough to rupture a person's eardrum?
In 2022, a Texas family filed a lawsuit against Apple for damaging their son's hearing after an Amber Alert went off while he was wearing Airpods. According to Google, the maximum volume of phone headphones is around 105 decibels. The family are claiming that the son now requires hearing aids after his eardrum ruptured.
Is this plausible?
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No not a few seconds. Ever walked near a jackhammer 130dB in the street for a few seconds? That is significantly louder. In general anything over 85dB for a significant amount of time causes damage. Concerts top out at around 110dB and you don't see people popping eardrums there.
However if you have an ear infection so some other type of damage then maybe?
I read Texas so I'm going to assume it was due to shooting guns
it's worth keeping in mind that dB fall off very quickly over distance and having a jackhammer right up next to your ear is different from passing a few feet beside it
Yes that's why dB measurements are always done in open air from 1 meter distance.
edit: Headphone measurements are obviously different and are optimally measured at the distance the eardrum sits from the speaker element, with similar encasing as the headphone model offers. For In-ear, it's a very low distance and a high level of encasing. Airpods will obviously not make 105 dB at 1 meter.
The 105 decibels is the max headphone output as it's placed in the ear.
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I can answer this conclusively for you, ear canals do not act as neither echo chambers or are subject to resonances for audible frequencies.
If they did you would have a literal ringing in your ears.
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Excellent question!
The energy is typically dispersed by hairs moving, muscles moving, eardrum moving, soft tissue deforming, the hearing system behind the ear drum, your eustachian tube, the movement of the ear pod against your outer ear, and the imperfect seal of the ear pod.
105 dB is probably the max sound pressure level at optimal seal.
Also, it's easy to verify, as resonance is literally the reason why violins, guitars and pianos have a ringing sound. Whereas regular sounds do not, because your ears don't have audible resonances (they do have resonances in other frequencies though, just as your eye sockets, lungs and other stuff).
Thanks for the explanation (maybe a little patronizing, but I assume it's in good faith). I found that 105 db is the average human pain threshold, and that NIOSH suggests a maximum exposure of 4.72 minutes at this db level. Still I don't know how long is an amber alert signal, but AFAIK they are played at the hardware max volume, bypassing the software limitations of the device, so maybe it was that.
Regarding the energy, mechanical energy tends to follow the path of least resistance, which for the ear is still the tympanic membrane with it's 0.1 mm thickness. Excluding hairs, which are extremely rare and small in a kid's outer ear canal, every other structure has a density far more superior, and with density comes inertia which impedes a swift "air to tissue" energy absorption. In a system like this a minimal imperfection in the eardrum tissue (and no tissue is perfectly regular in the human body) is a weak point which can lead to rupture. Also the ear canal is usually a mild funnel, so there's also an ulterior compression of the air happening inward and towards the eardrum.
As for resonances, I too don't think that they play a significant role in the case.
Well said!
yeah, i agree; you're not a doctor...
But you are a jerk
Sound pressure falls off as a function of the square of the distance. So if that jackhammer is 3 m away you are only receiving 11% of the sound energy that the operator is.
I think it's very different if it is a clean digital noise. Acoustic sounds, even when loud, have a brief ramping up. Digital noise can appear like a wall from zero to 110dB in literally zero time for the ear to adjust.
The ear has tiny hairs that
raise to absorb sound and protect the hearing(see comment for a correction). I know of somebody that had a digital noise cut right through them and cause permanent hearing loss. Their hairs were flattened and no longer work. I don't know the amplitude though.This makes no sense. For sound to actually become sound, it becomes acoustic by definition. It cannot be sound unless it moves the air or any other element that can move Soundwaves.
The source of the sound is the speaker element of headphone. I thought that detail was obvious. A speaker reproduces any signal fed into it as to best of it's abilities. Acoustic recordings, sounds mimiking acoustic sounds, analogue or digital synthetic sounds, static noise... And even a digital pulse that goes from zero to maximum amplitude in one instant that is extremely rare or near impossible for even the most aggressive acoustic sounds. Acoustic or analogue noise is basically a sum of random frequencies all playing at once, while digital noise is a constant stream of random clean digital pulses.
Earbuds that aim to create a seal in order to isolate from external noise are dangerous in particular as there is nowhere for the sound waves to dissipate. Some parts are absorbed by the flesh of the ear canal but other parts become resonant waves that only add to the amplitude and hence the stress to the ear drum.
I had a pair of faulty ANC earbuds that would make digital pops. They weren't necessarily louder than the music playing but damn they hurt like an unklefucker. It was like pure spike of treble cutting through the ear straight into the brain. The type of sound our ears have never encountered naturally in all their years of evolution.
Just want to chime in and mention those tiny hairs aren't protective. They're hair cells, named because they have tufts of stereocilia, and are what your ear actually uses to hear. When they die, you lose hearing. There are two types, inner and outer, and while the outer can influence the amount of sound detected by the inner hair cells, they can only amplify, not reduce.
The ear protects itself against loud sounds by contracting the tensor tympani and stapedius muscles, dampening the eardrum and tensing and shifting back the ossicles, the small hearing bones of the ear. This all serves to reduce the amount of force transmitted to the inner ear but takes time to occur, so it can't protect against sudden loud noises, like a gunshot.
Oh, thanks for the correction. I seem to have misunderstood the injury when I got it described to me.
No worries! From your comments, you seem to be a bit of an audiophile. Just watch out, because audiophile forums are FULL of authoritative sounding BS.
Haha, uh oh, I will try to not take offence. I'm in no way an audiophile, though I do have a nice stereo system for listening to music rather than listening to the equipment. I did venture into doing sound based arts and installations and stuff when I was younger though so I do have some insights of how sound works. It was a "colleague" l knew back then that had the injury mentioned from an incident in a sound studio. If memory serves me right it was an accidental digital feedback loop that hit the ears like a brick wall and despite it was less than a second it was enough to cause permanent damage.
You're almost right in so many aspects it unfortunately becomes utterly wrong.
Digital and analog noise aren't real things, or at least not the words that are used for it. Digital and analog noise has to do with signals and frequency spectrums, not with the actual pressure differentials that are physical sound waves.
But there is a similar concept, where a thing happening can create a strong pressure wave, typically called an air blast, and are common when talking about blasting and other explosions (where the pressure wave is significant, but not really a noise). Ear pods do not create a significant pressure wave.
The ear does have tiny hairs for hearing, and they do break at sudden and loud noises (@soleinvictus explained our defence mechanisms brilliantly in another reply) and also at repeated exposure to loud noises. A breakage typically results in partial, temporary, hearing loss and "ringing in your ears", whereas permanent death of the sensory cells leads to tinnitus, which isn't the same as hearing damage/loss.
Sigh. Acoustic vs digitally generated noise.
Acoustic noise is what you hear outdoors from the wind, waves, leaves, whatever. An absolute myriad of tiny impact noises and scrapes and brushes and whatnot mixed together that become a dense complex texture that can be characterized as noise, although technically it is just a massive amount of single individual sounds. Acoustic noise can be found in many frequency ranges but human ears are generally good at handling with the common organic ones. Thanks, evolution!
Digitally generated noise. A sequence of random1 values that plays at the frequency rate of whatever means of digital to analog conversion is used. Digitally generated white noise consists statistically2 of all frequencies within the range of the sample rate at all volumes reproducible by the bit depth.
Digitally generated noise3 is not limited by common physics for generating sound waves4, but can be of any frequency range at any amplitude, i.e. pressure differential, within the range of the means of digital to analogue conversion and playback. That is, potentially in a spectral distribution of sound that is straight up painful for human ears.
However, the big difference is that digital noise is not a mix of endless impact noises or brushes or whatever that each follow an envelope curve, but are rather a sequence of shifting values without transitory ramping, i.e. pulses. That is, a sequence of shifts in air pressure that is literally as fast as it can possibly be.
Note that in the case of glitching5, the digitally generated noise may be limited only by the physical properties of the hardware and goes beyond what amplitudes the equipment is artificially limited to for pleasant and non harmful playback of music.
Can headphones or earbuds or loudspeakers reproduce a digitally generated noise in frequencies that are painful in amplitudes that are harmful for the human hearing apparatus? Oh, I think they do.
Anyway, I trust you are correct in your other point. It seems I used the wrong medical terminology as I was silly enough to speak in vernacular as non native English speaker without medical expertise. I expected to get away with a delirious misnomer to call years of continuous tinnitus and distorted audio perception a permanent hearing damage when it is clearly not.
My apologies for causing confusion.
1 Since attention to details are important; Most likely pseudo random generated. I know. I know.
2 Details, people.
3 Any digital noise. Audio that has been distorted until it has a frequency distribution that can be confused as pure noise, a data stream not intended for audio playback, a software/hardware glitch that flips significant bytes rapidly enough to cause a sequence of pops in such density it is perceived as a burst of noise. Whatever, use your imagination for further examples.
4 In our living conditions, on planet earth, at this time.
5 Generally speaking, not specifically to any example mentioned in this context.
I'm also not a native english speaker, but I am however a professional acoustician. I'm not opposed to you defining your terms in a way uncommon to both acoustics and audionomy, and with this explanation they're clear, although I don't understand how the contrast is relevant to the topic. No matter how the signal is created, it will have to be a pressure wave of amplitude and frequency, travelling through a medium, like air, to reach an ear.
However,
Can headphones or earbuds or loudspeakers reproduce a digitally generated noise in frequencies that are painful in amplitudes that are harmful for the human hearing apparatus?
Headphones and earbuds certainly can produce harmful amplitudes, that is why most of them are designed to be physically limited not to be able to. This is what the upper limit OP mentioned usually refers to, the maximum physical level the ear plug can produce. Limited by available airflow, membrane, driver, power, and seal.
Dude, I'm not trying to speak like a acoustician. At closest I'm speaking as an engineer with some knowledge of sound and acoustics from ages ago or maybe a musician, I don't know. If you expect random people to use professional terminology to have a conversation it's really your own mistake. I mean it in a constructive way from my own experience of taking with people on whatever I happen to know more about than them.
The contrast of a pulse as a rapid shift of air pressure and multiple ones in rapid succession of high amplitude in the context of causing damage to the inner ear? I am honestly struggling how to explain it any clearer.
Ok, I'll give it one more go.
As you say, it is not important what or how the pulse or burst of pulses are created, but digital to analog conversion of a signal can create impulses that are literally as rapid as can be by the laws of physics that are extremely rare organically and in particular by amplitudes that you get in headphones. A burst of such impulses, I'm avoiding the previously used terminology, of random but high frequency and amplitude is like having a tiny plunger jerking like crazy in your ear like nothing the ear has ever evolved to be able to deal with.
Not because digital vs analogue, vinyl vs CD vs mp3, gold plated monster network cables or helium cooled SPDIF connectors. No magical thinking. Only changes in air pressure. Changes in air pressure of the very fast and strong variety.
But good sir, a rapid change in pressure is the same as a high frequency sound wave.
It makes little difference if it has a long duration (a tone, or noise) or short duration (a puff of air).
And the higher frequencies neither carry more energy, nor are more damaging than lower frequencies.
But you are right in that the ramp up in amplitude matters, and which could theoretically be over a very short time period either in frequency or duration with the same amount of damage. In ear plug practice this would however be limited by the electrical pulse in the driver (both wattage and Hz), and the viscosity of air flowing through the back of the speaker cavity.
A significant ramp up is what is typically meant by high maximum instantaneous sound levels, LpFMax, and those are typically long term damaging at >115 dBA, unless other risk factors are present.
(Just to be overly clear, I'm not faulting your use of language (once I understood what you meant), you're doing admirably, and I fully understand that language is malleable and context dependent - I'm not hung up on the words.
I'm trying to get to your understanding of the physics behind it, which I read as a little muddled. It could still be due to language barrier, but what I pick up is some confusion in the differences between frequency domain and physical domain.)
On the other topics, which you seem to understand, but I'll try to explain again to see if our models can better converge:
On the topic of the tiny plunger, this is actually how virtually all speaker elements generate sound. You have a little element, called the driver, pushing on a membrane in the frequency and amplitude you're trying to convey. The driver and membrane can't be infinitely flexible or have infinite plunging depth, lest they need infinite energy to push an infinite amount of air, and so are typically carefully designed to certain specs, called dynamic range (frequency/speed of driver), and sound power (amplitude of driver).
As to what the ear is designed for, it is actually very well protected against high frequencies, this is a large part of why we can't hear higher frequencies than ~20 kHz. But you are right that it's not made for sudden loud noises (a steep ramp up in amplitude). And although I don't actually know, my motivated guess would be that human reaction time for the protection against sudden loud noise is at best 1/8 th of a second.
Yes, we agree on most everything and my understanding of both physics, mechanics and biology seem to agree with yours.
I guess the one main disagreement is if a pulse, either single or repeated, might potentially be more harmful than a sine wave of a single frequency. According to the teachings I've had, or my recollection thereof, a pulse or impulse may carry the sum (or zero sum) difference if any ramping wave, but the nature of the impulse it literally hits differently. A transition of difference in state versus a forceful immediate change. A push or a slap. Or a push and pull versus a slap and yank, should we speak of a complete cycle.
This was what I attempted to illustrate with the plunger example. If you are familiar with a plunger, you'll know that the method of operation is not to keep a harmonious cycle, but to yank it aggressively in order to transmit a whole lot of impulse-like energy and forcefully release buildup or blockage in the pipes. My argument is that should we have two identical sinks with identical blockage and we'd manage to conduct an experiment where both plungers operate at identical frequency and amplitude, but that one plunger pumps in a harmonious cycle while the other does a pulse-like push pull, the latter would yield more successful results. Hence my conclusion is that despite the state being identical before and after, theoretically the amount of energy may be the same, there is a difference in how the energy is transferred depending on the curvature of the actuation on the plunger. Or the speaker cone. Though through air instead of water and air compress while water doesn't. But still.
So the frequency of a repeated waveform and the shape of the waveform are not interchangeable. I'm sound the frequency carries the root tone, the shape carries the multiples. A perfect impulse (or other digitally generated waveforms) carry in theory an infinite amount of frequencies. Again, carry may be a misnomer depending on the discipline and of course the perfect is unobtainable so in practice the frequency spectrum is limited to one bandwidth and spectrum or another. Not that really had any bearing in our discussion.
Finally, I disagree with the argument of the engineering in headphones. Those limits are with respects of quality of sound reproduction. They are not a guarantee of hard limit of potential output and not intended to be. I don't engineer speakers but it's quite common paradigm in engineering in general that you benefit in quality and reliability should you accept a modest degree of unused overhead. Mistakes and bugs happen and it is especially vulnerable when it is reliant on hardware and software in the earpiece itself, as with my personal experience of faulty earbuds that emitted bursts of painful high frequency noise despite playback being of moderate volume. There are no intermediate steps of filtering, as with analogue gear, so should a faulty component cause a pop, it may well do so from the one extreme to the other.
I apologize for my frustration. I've been experiencing lately that I try to communicate one thing and the recepient keep projecting it into their own frame of reference and insist I'm talking of something that I'm not. I'm a bit touchy and I'm sorry about that.
Thank you for taking the time to explain, we do indeed seem to be closer to each other's understanding.
So the frequency of a repeated waveform and the shape of the waveform are not interchangeable. Hence my conclusion is that despite... theoretically the amount of energy may be the same, there is a difference in how the energy is transferred.
This is contrary to what I remember having been taught about biomechanics and hearing, but as memory and understanding is unreliable, I'll cede that I'd need to look up a reference for better precision.
The crux of my argument hinges on there not being a difference. And my understanding of the physiology is that the hairs will primarily bend with pressure, and exhaust with flexion (repeated bending cycles leads to breaking), within the limits of survivable amplitudes.
If there isn't a difference, my argument continues in that it's physically very difficult to create a pulse with a ramp up faster than the 20 kHz the ear is evolved to take, that's 0,05 ms, not many physical processes go that fast to create a pressure wave and those that do typically get dispersed very quickly, unless as part of a harmonic excitation.
But of course all that is irrelevant if that's not how the ear reacts.
headphones. Those limits are with respects of quality of sound reproduction.
You may be right, the details of what the measure represents haven't been presented.
From context where it's being argued as a legal argument, I have assumed it to be part of the safety design, and not of sound reproduction.
Ear phones/plugs have no business reproducing good quality sound at >100 dBA, and would be sued into oblivion as the hearing damage and tinnitus reports rolled in. Which to be fair, is what the OP is about.
Having a physical limit at 105 dB would then be congruent with the same unused overhead you refer to, as it corresponds to a doubling of potential sound pressure, and is about typical as overcapacity for high fidelity engineering applications.
faulty earbuds that emitted bursts of painful high frequency noise despite playback being of moderate volume.
105 dB would probably be painful, and as a surprise would be jarring, which contributes to the perceived risk of injury. It should also not be loud enough to cause lasting physical injury, and you'd typically have full functionality within two weeks.
An earbud/head phone can be designed failsafe, so that casing, driver, or most commonly membranes will break at too high amplitudes. If nothing else, it will be limited by the amount of energy available, which for wireless or portable headphones is typically very low. I can't vouch for the specific gear in the OP, but given the rarity of recalled gear due to injury, I'd guess it would be widespread industry practice to design it fail safe.
What I'm saying is that it can still be hardware/physically limited at 105 dB, even though it gave a painful squelch before breaking.
I apologize for my frustration. I've been experiencing lately that I try to communicate one thing and the recepient keep projecting it into their own frame of reference and insist I'm talking of something that I'm not. I'm a bit touchy and I'm sorry about that.
I totally get it, it's a built in flaw of the Lemmy/social media format. Too little supportive language cues, and too little time and/or investment to actually listen.
I appreciate you having the patience to talk this through with me.