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this post was submitted on 06 May 2024
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No Stupid Questions
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There is no such thing as a Stupid Question!
Don't be embarrassed of your curiosity; everyone has questions that they may feel uncomfortable asking certain people, so this place gives you a nice area not to be judged about asking it. Everyone here is willing to help.
- ex. How do I change oil
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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.
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.
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.
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 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.