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Custard Earmuffs

Defend your ear holes
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Attenuation is what most earmuffs or ear defenders do. They make all sounds quieter, which, while protecting your ears, also make conversations difficult.

Compression (or dynamic range compression) is what an ideal earmuff should do. Attenuate the loudest sounds, but let the rest through unmodified. No doubt electronics could produce a dynamic range compressing earmuff, but, what if there were some material available, to fill the earmuffs, that let small sounds pass but thickened when the noise level got too loud?

Custard Earmuffs.

mitxela, Jun 13 2016

Patent US20130153328 https://www.google....tents/US20130153328
"the sound absorbing material comprises of a thixotropic material" = custard [mitxela, Jun 16 2016]

Sodium Acetate https://en.wikipedi...acetate#Heating_pad
Useful [8th of 7, Jun 16 2016]

[link]






       This is excellent, apart from the problem that solids transmit sound about as well as liquids.   

       A better option might (or might not) be earmuffs filled with a gas that was on the verge of condensing. Then, high-pressure sound waves would cause local condensation of the gas, absorbing the sound. Smaller sounds would pass unhindered.
MaxwellBuchanan, Jun 13 2016
  

       Bose-Einstein headphones?
Ian Tindale, Jun 13 2016
  

       Szilard-Einstein headphones.   

       //A better option might (or might not) be earmuffs filled with a gas that was on the verge of condensing.//   

       That would work wonderfully unless there were any variations in local temperature or pressure. Being entirely vulnerable to the weather never stopped the good people of the 1970's British motor industry though, so maybe a viable product.   

       Actually, if you could get the active part IN the ear canal, that would take care of the temperature and pressure differences could be accounted for by a little piezoelectric doodad to shift the volume about very slightly.
bs0u0155, Jun 13 2016
  

       // the weather never stopped the good people of the 1970's British motor industry //   

       ... although it did very effectively stop their products (Austin Allegro, anyone ?).
8th of 7, Jun 13 2016
  

       The Austin Allegro was superb piece of engineering and years ahead of its time. That some people foolishly insisted on using it as a car was something the manufacturers could hardly have foreseen.
MaxwellBuchanan, Jun 13 2016
  

       // Austin Allegro was superb piece of engineering and years ahead of its time//   

       Ah yes. At some point I expect NATO documents to be declassified detailing the Austin Allegro as a top level dis- engineering project designed to fool the Soviet Union into thinking that the UK was incapable of producing functional mechanical products. The Allegro was even exported and assembled in Italy by Innocenti, where Soviet intelligence would conclude that the British couldn't design a functional car and that the Italians had given up on the concept of aesthetics. This masterstroke of a project sowed considerable doubt among all levels of Soviet society. Did the British posses the kind of engineering prowess that allowed a person of reasonable means to drive an E-Type Jag to the airport and hop on Concorde and be in New York in time for Lunch? Or did they put rubber suspension on bad looking cars, fit them with rain-soluble electrics and then paint the whole thing brown?   

       A confusing effect for the Soviets, I'm sure.
bs0u0155, Jun 13 2016
  

       No less confusing than British Leyland's master-stroke against the Teutons, the Triumph Acclaim, which translates very nicely as "Sieg Heil !" ...   

       ("Sieg",n, victory, success, triumph, conquest; "Heil", v, hail, applaud, acclaim, welcome).   

       Very confusing.. at one extreme, the Supermarine Spitfire, the cavity magnetron, and proper drains; at the other, the British Rail "pork" pie, the steam-powered submarine, and the Austin Princess.   

       // sewed //   

       Sp. "sowed"
8th of 7, Jun 13 2016
  

       //at the other, the British Rail "pork" pie, the steam- powered submarine, and the Austin Princess.//   

       Better than the British Rail submarine, the Pork Princess and Austin Steampowers.
MaxwellBuchanan, Jun 14 2016
  

       Would Jethro Tull have been the first person in history to say “Make it sow”?
Ian Tindale, Jun 14 2016
  

       Why do you think this would work?
ytk, Jun 14 2016
  

       sp: all agro
po, Jun 14 2016
  

       sp.: "sp. All aggro".
MaxwellBuchanan, Jun 14 2016
  

       // sp.: "sp. All aggro" //   

       Sp. "Allegro"
8th of 7, Jun 14 2016
  

       // solids transmit sound about as well as liquids // True, but although I have no evidence to back this up, I was assuming the transition from liquid to solid would absorb a lot of the energy.   

       But it has come to my attention that, just like almost every other idea that's ever been or will be imagined, custard earmuffs have already been patented. <link>
mitxela, Jun 16 2016
  

       //I was assuming the transition from liquid to solid would absorb a lot of the energy//   

       Ah, right - in that case, it is not such a stupid idea after all*. I'm not sure how much energy is absorbed in the transition, though.   

       [*irrelevant aside: I was once discussing some work I was doing with another guy in the lab. He suggested something and I thought about and then said "You know, that's not such a stupid idea." Another colleague who was present told me later that that was not necessarily something good to say to a Nobel laureate.]
MaxwellBuchanan, Jun 16 2016
  

       // how much energy is absorbed in the transition //   

       That's only part of the problem. Like "instant-heat" pouches <link> the energy can be absorbed by a state-change; but then it has to be dissipated (as heat, usually) or the device will saturate.   

       Walking round with two pots of hot custard strapped to your head may get you some funny looks, and quite possibly a compulsory treatment order.
8th of 7, Jun 16 2016
  

       Hmm, the patent describes thixotropic solutions. These are shear thinning. This makes sense. Essentially incident sound energy is transmitted to the ear via shear forces through the sheer thinning substance. Increased amplitude decreases the percentage of force transmitted. Nice. Strangely the patent describes a whole lot of shear thickening substances...   

       You could achieve the same effect with a shear thickening liquid, increased viscosity could be used to increase the amount of force applied to an embedded damper. For example you could have an external membrane, an internal membrane with a custard filled interior. If you embed a coarse grid between the two membranes connected to the frame, then as amplitude increases more of the sound energy will be transmitted to the grid, cylinder and frame of the ear piece rather than going to the air on the other side.
bs0u0155, Jun 16 2016
  

       //the energy can be absorbed by a state-change; but then it has to be dissipated (as heat, usually) or the device will saturate.//   

       I think the idea's about changing state during the compression bit of the waveform, then back again during expansion, so no buildup of energy (that's another idea).   

       //Austin Allegro// looks like different sections were separately designed by different blind people. I can however see some bits which Honda ripped off for their late 70's Civic.
FlyingToaster, Jun 16 2016
  

       // ripped off //   

       That implies the use of force, which is clearly ludicrous. It's possible to detatch major structural components with no more effort than a hard stare.   

       More likely, the bits in question were simply collected from where they were lying in the gutter.   

       At speeds over 23 mph, the cheap adhesive tape holding the vehicle together starts to fail, causing debris (doors, fixed glass, engine) to fall off.   

       Fortunately, Allegros can't attain 23 MPH*, which is fortunate for the drivers; after all, they've suffered enough already...   

         

       *Except in free-fall, caused for example by being pushed off a sheer cliff. Quite remarkable how often that happened.
8th of 7, Jun 16 2016
  

       I think it is better to have a computer recreate the extererior sounds swapping out words to be from preferred vocabulary. so "expletives" become   

       sexual activity!, sexual activitying sexual activity!, what the sexual activity do you think you are doing! sexual activity. Make love, omit war.
beanangel, Jun 17 2016
  

       Fuckin eh.   

       ^Dammit, beanangel trumps me every time..
not_morrison_rm, Jun 20 2016
  

       The verb "to Trump" is becoming less positive as time goes on.
MaxwellBuchanan, Jun 20 2016
  

       Hmmm .... is "Clinton" a verb, or a noun ? We ask merely for information...
8th of 7, Jun 20 2016
  

       // I think the idea's about changing state during the compression bit of the waveform, then back again during expansion, so no buildup of energy (that's another idea). //   

       Then where does the energy go? It must still be dissipated somehow. (Pressure is conserved in the mechanism you describe, but energy apparently is not.)
notexactly, Jul 17 2016
  

       ^ The crest of the wave hits the medium with enough force to change its state. The phase change keeps some of the energy to itself, thus the transmitted waveform is attenuated in its compression stage.   

       Then the trough comes along with enough force (in the other direction) to change the phase back, releasing the energy which fills the trough a bit, thus attenuating the waveform in its rareification stage.   

       It's similar to simply piling on enough material that the sound is dampened, but more fun and, presumably requires less material.   

       Not completely inanalgous to an IBM "buckling spring" keyboard, where you push down against tension which suddenly becomes less (as the spring buckles, storing some energy), said energy storage returned to the finger when you release the key and the spring unbuckles. If there were a pressure sensor under the keyboard frame it would measure a square'ish wave as the crest and trough were chopped off by the spring buckling and unbuckling, storing/releasing energy.   

       Which is probably what [mit] means.
FlyingToaster, Jul 18 2016
  

       I understand that part (I think). Kinetic energy from the sound wave is during a crest turned into thermal energy via the phase change. But then, during the trough, the phase change is reversed and the energy goes back into the sound wave. This would seem to result in the sound wave having the same amount of energy as before.   

       (Actually, it occurs to me now that the phase change from solid to liquid or liquid to gas would be initiated by pressure drop (trough) and the opposite phase change by pressure rise (crest). But the reasoning should still hold.)   

       You can (assuming we're not both wrong) fill troughs with pressure from crests because pressure is a value that can be positive or negative (relative to ambient). You can't do the same with kinetic energy; that's only positive. So something weird is going on.
notexactly, Jul 20 2016
  

       A compression to solid and a relaxation to liquid are different. One is more ordered and the other more random. Think about plinko, getting the ball bearing up the board, to the top of the hill, is a finer path compared to coming down.   

       I imagine the custard will convert more energy in packing process during the compression.
wjt, Jul 22 2016
  
      
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