what is the loudest possible way to play back a sound recording?
December 17, 2005 12:53 PM   Subscribe

what is the loudest possible way to play back a sound recording?
posted by enrico de giove to Technology (23 answers total)
 
any more specifics?
play what, through what?
posted by herrdoktor at 1:01 PM on December 17, 2005


I don't really think there's any limit, if you have an ulimited speaker budget.

However, one thing I thought of would be to use exploding gas (like in a car engine) to generate sound waves. I think you could get a lot more volume that way then through an electrical speaker (just like how you can get more energy out of an engine then a motor per unit of weight)
posted by delmoi at 1:06 PM on December 17, 2005


Rent concert equipment. One player, one amp, however many speakers. You can in fact make it loud enough to hurt yourself.
posted by Ken McE at 1:06 PM on December 17, 2005


'Loudness' has a limit - when the intensity of the sound wave gets to 1*10^4 W/m2 your eardrums are going to be punctured and it can't get any louder however much you increase the intensity.
posted by lunkfish at 1:14 PM on December 17, 2005


Then you have to use a subwoofer up the arse.
posted by lunkfish at 1:16 PM on December 17, 2005


Wtf does "1*104 W/m2" mean? 1*104 = 104. Did you mean 1*104?
posted by delmoi at 1:17 PM on December 17, 2005


yeh
posted by lunkfish at 1:19 PM on December 17, 2005


World's most powerful subwoofer (/.)
posted by TimeFactor at 1:27 PM on December 17, 2005


Mod note: tried to make the 104 thing look more sensible
posted by jessamyn (staff) at 1:31 PM on December 17, 2005


Loudness and volume have different meanings, distinct from total energy output. (per acre? per square mile?)
posted by StickyCarpet at 1:43 PM on December 17, 2005


You might be interested in the first act of this This American Life episode. It's about decibel drag racing, where competitors have cars with stereos so big the cars are almost undriveable, and so loud they'd deafen you if you were inside.
posted by driveler at 1:53 PM on December 17, 2005


Turn the amp up to eleven?
posted by stopgap at 1:54 PM on December 17, 2005


IANAAudiologist, but why not bypass that pesky Rube Goldberg contraption in the middle ear? I'd guess if you did it right you could stimulate the perception of sounds that, if transmitted the normal way, would destroy the eardrum (or worse.)

Implementation is left as an exercise for the reader.
posted by Opposite George at 2:12 PM on December 17, 2005


Opposite George: hmm yes. Strap some sucker down and electrically stimulate the auditory nerve directly. Interesting...
posted by NucleophilicAttack at 2:27 PM on December 17, 2005


There is an upper limit to the number of decibels about the threshold of hearing to which an audio sine wave can be generated without distortion at standard temperature and pressure. Somewhere around 154 decibels, I believe. It has to do with the fact that you can compress air a lot more than you can rareify it, i.e. once you reduce the pressure in a region to zero you've nowhere left to go.
posted by ZenMasterThis at 2:43 PM on December 17, 2005


Strap some sucker down and electrically stimulate the auditory nerve directly.
I just hope they aren't reading this at Camp X-Ray.
posted by Opposite George at 3:14 PM on December 17, 2005


If there were air around a supernova for it to vibrate, and one could orchestrate the timed explosions of various sizes of supernovae to go off in exactly the right ways, I'd think that such a series of supernovae chain reactions would be the loudest possible rebroadcast, no?

enrico didn't ask "that a human could hear" but simply "the loudest", in all truthful ways, barring even unliklihood of actually accomplishing it.. but this brings up an interesting question -- would the listener determine how loud something is? Such as a bloodhound can detect scent (thus a scent being of normal intensity to a human being more significant to a bloodhound), would someone with ultra-sensitive hearing detect sound as much louder than humans normally interpret it?
posted by vanoakenfold at 4:26 PM on December 17, 2005


I don't remember much from fluid dynamics class in undergrad, but if we're talking about pressure waves in a fluid then aren't they going to be physicaly limited by the mach number of the medium? So given a set of material properties (in this case air at STP), could you not find this velocity and pressure? Of course this says nothing about perceived volume since your eardrums would have long been shredded, but I think most people have covered the human physiological aspects of the question already.
posted by Rhomboid at 4:52 PM on December 17, 2005


Strap some sucker down and electrically stimulate the auditory nerve directly.

Makes for an interesting question: how loud can we perceive a sound to be? To what extent is "really loud noise" a strictly auditory sensation vs. other sorts of nervous input in the mix?
posted by cortex at 6:16 PM on December 17, 2005


The auditory nerve is adaptive... Constant and constantly repetative sounds are attenuated in the brain. So, you would have to find a signal that would get through at full volume...
posted by Chuckles at 8:59 PM on December 17, 2005


So, you would have to find a signal that would get through at full volume...

May I propose as a candidate the shriek of the Bridgeport Monk Parakeet, especially when a flock of them goes by the window at 2 a.m.
posted by Opposite George at 1:43 AM on December 18, 2005


IIRC, Bruce Edgar (or was it Nelson Pass?) did a couple of speaker arrays for a military contractor that needed to simulate artillery explosions.

But direct-radiators (eg, traditional speakers) are never going to be as efficiently loud as a compression driver. Without specifiying a particular frequency range, I can only point you to the undisputed masters of over-the-top audio, Ale.

See the last listing? the P160? It's 200 pounds. It'll do 110 dB at 20 Hz. That is unpossibly loud and low. Like really, really, really loud.
posted by Triode at 2:53 PM on December 18, 2005


Triode, you should really check out TimeFactor's World's most powerful subwoofer link - here's the product page. Probably not the lowest distortion/noise solution possible, but a brilliant idea.
posted by Chuckles at 8:57 AM on December 19, 2005


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