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Can a speaker break the sound barrier?
Old 19th May 2012
  #1
Gear Nut
 

Can a speaker break the sound barrier?

For example, if it could produce a transient quickly enough or produce a near perfect square wave? Would this make the speaker too good in a sense that it produces effects that would never translate to the home listening environment?
Old 19th May 2012
  #2
Gear Addict
 

Speakers shouldn't produce effects, they should only reproduce them....so if your instrument is producing the effect - you can't really go wrong hearing it accurately. Yea maybe in theory no one else would hear it quite the same. I remember a story about Meyer HD-1's nearly reproducing true square waves, but I think that's physically impossible with linear motion.
Old 19th May 2012
  #3
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RRCHON's Avatar
Speakers on aircraft capable of super sonic flight break the sound barrier on a regular basis.

BTW some information of SPL in dB

0 (N) BEGINNING OF HEARING, A MOSQUITO 10 FEET AWAY, THE EAR DRUM MOVES LESS -REF.1.1990

3.5 (P) 1E-10 METERS OF MERCURY = 0.0000000001 METERS OF MERCURY
10 (P) ABSOLUTE SILENCE, ATT-BELL LABORATORY “ QUIET ROOM “
13 (P) ORDINARY LIGHT BULB HUM

162 U.S. FESTIVAL ROCK CONCERT 1983. 10 SEPARATE STACKS, AMPS = 400,000 WATTS (N) -REF.1.1983,-REF.3.

195-190 (P) HUMAN EARDRUMS RUPTURE 50 % OF TIME -REF.2.

212 (N) SONIC BOOM AVERAGE FROM JET -REF.5.
213 (N) SONIC BOOM GENERATES APPROXIMATELY 1.2 GIGAWATTS OR 1.6 MILLION HORSEPOWER -REF.1.2002
213 (N) BOMB 1 TON TNT, 23 FOOT WIDE CRATER OR 175.8 db (P) AT 250 FEET. 213.44 EXACT -REF.1.2.4.

248 (N)ATOMIC BOMB-HIROSHIMA AND NAGASAKI JAPAN AUG. 6, 9, 1945.


Reference Link


It does not have to get that loud though the sound of whip cracking is actually a few fibers on the end of it breaking the sound barrier, you could probably calculate how many watts it would take to move the average speaker membrane at a broadband frequency to accelerate fast enough along its range of full motion so that it can accelerate past 340.29 m/sec a sea level. You could do a simple physics version no accounting for air viscosity or membrane resistance ect...

have fun with it.
Old 19th May 2012
  #4
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Laurend's Avatar
 

Quote:
Originally Posted by Roboticus View Post
For example, if it could produce a transient quickly enough or produce a near perfect square wave? Would this make the speaker too good in a sense that it produces effects that would never translate to the home listening environment?
What is a "near perfect square wave"? It's just as perfect as the whole audio system bandwidth allows it to be. So your question can be reformulated as: "Do I need a larger bandwidth for production than that of the final user system?"
The better is your monitoring system, the better is the final result. "Too good speakers" don't exist.
Note also that some audiophiles use the same grade of speaker than mastering facilities. So you can't make any assumption on the final bandwidth if an analog support is used. When using digital media for audio, the bandwidth is standardized for both production and distribution.
Old 19th May 2012
  #5
Gear Guru
 

rail guns are also powered by magnets, and they can accelerate a piece of metal to about 5,400 mph - that's around Mach 35

[edit]: correction about Mach 7

so there might be a way to build a speaker to accelerate the cone to high speed, but that could be kind of dangerous if it doesn't at some point stop accelerating towards you and begin going back the other way.


Old 19th May 2012
  #6
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Laurend's Avatar
 

Here's one solution to enjoy the 96KHz sampling rate.



Because they have no other moving part than the gas, plasma speakers are good for ears. But ozone and nitrous oxide are harmful for lungs... I've never seen any in a mixing or mastering booth.
Old 19th May 2012
  #7
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frans's Avatar
Quote:
Originally Posted by Roboticus View Post
For example, if it could produce a transient quickly enough or produce a near perfect square wave?
A square wave is a fluctuation in electron flow (simplification, okay?), the speaker is trying to push some mass (voicecoil, membrane). Mass versus energy - energy is rather devoid of inertia, mass has it. So as long as you try to build a speaker with a moving mass, it will have problems following a square wave very closely. (and most other signals at well...)
A square wave is the loose attempt of a electrical signal to try and follow a theoretically infinite series of overtones, therefore even the square wave fails.

But to get back on topic, a good speaker will follow the signal "good enough" and for audio transmission without speakers you could sink a little time into the research of this man:
https://en.wikipedia.org/wiki/Patrick_Flanagan
Old 19th May 2012
  #8
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filipv's Avatar
Quote:
Originally Posted by Roboticus View Post
For example, if it could produce a transient quickly enough or produce a near perfect square wave? Would this make the speaker too good in a sense that it produces effects that would never translate to the home listening environment?
Square wave cannot be produced by any speaker.

But, theoretically, if a speaker is physically BIG and POWERFUL enough and fed with sine (not square) wave, there is no natural principle which will stop the HUGE cone to cross the neutral position with speed greater than the speed of sound. Mind you, in that scenario the speaker will produce heat and noise (mostly heat) rather than sound, so I doubt anybody will ever produce such speaker.
Old 19th May 2012
  #9
Isn't there enough to worry about with audio already?!
Old 19th May 2012
  #10
Old 19th May 2012
  #11
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filipv's Avatar
Quote:
Originally Posted by psycho_monkey View Post
Isn't there enough to worry about with audio already?!
:-) too much is not enough?
Old 19th May 2012
  #12
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Pezz's Avatar
 

the only way a speaker will break the sound barrier is if you put it on concorde
Old 19th May 2012
  #13
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filipv's Avatar
Theoretically, the speaker could be standing still and still the cone could be traveling faster than mach 1. I'll explain if there's an interest in the explanation.
Old 19th May 2012
  #14
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erikdrink's Avatar
Interesting thread!
Old 19th May 2012
  #15
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Laurend's Avatar
 

Quote:
Originally Posted by filipv View Post
Theoretically, the speaker could be standing still and still the cone could be traveling faster than mach 1. I'll explain if there's an interest in the explanation.
Still and traveling! please, explain.
Old 19th May 2012
  #16
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Quote:
Originally Posted by Roboticus View Post
For example, if it could produce a transient quickly enough or produce a near perfect square wave? Would this make the speaker too good in a sense that it produces effects that would never translate to the home listening environment?
I wouldn't worry. Since we are generally listening at ambient air pressure of about 1 atm or 100 kPa, and instantaneous sound pressure is the deviation from that ambient pressure, undistorted sound is possible up to the point where the valley of the wave reaches zero pressure at about 194 dB SPL. In a studio setting, the loudspeaker is not moving, so the pile up of wavefronts from a supersonic source is not relevant.

Cheers,

Otto
Old 19th May 2012
  #17
Quote:
Originally Posted by Pezz View Post
the only way a speaker will break the sound barrier is if you put it on concorde
Arn't the survivors all in museums now?
Old 19th May 2012
  #18
Gear Nut
 

So in theory, a speaker that could produce a square wave that accelerates fast enough to break the sound barrier would sound like a cracked whip on buffer repeat. Now if I were to record the crack of a whip and put it through a beat repeater, what would happen?
Old 19th May 2012
  #19
Gear Guru
 

Quote:
Originally Posted by Roboticus View Post
Now if I were to record the crack of a whip...

remember that while the tip of the whip is moving faster than the speed of sound, the sound it makes will only move at the speed of sound.


it is doubtful that your microphone would capture the full thing

NASA uses special mics and techniques just to measure sonic booms, but I don't think they are trying to actually capture or record one, much less play it back.


If you set off an explosion, you can create a hypersonic shockwave, but it would probably damage the mic. The speed of the shockwave varies with the amplitude.

It seems to me that unless the mic's diaphragm itself moves faster than the speed of sound, it can't capture something that would produce a hypersonic movement of the speaker when played back. Most likely the physical inertia of the diaphragm would dampen the ability to fully react to a hypersonic impulse. The impulse would be over before the mic's diaphragm had really started to move.
Old 19th May 2012
  #20
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Sperm Whales can produce a sonic wave at 230 dB underwater. Equivalent to 170 on land.

They use it for echo location and supposedly stun their prey (giant squid).

Old 19th May 2012
  #21
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Quote:
Originally Posted by Roboticus View Post
So in theory, a speaker that could produce a square wave that accelerates fast enough to break the sound barrier would sound like a cracked whip on buffer repeat. Now if I were to record the crack of a whip and put it through a beat repeater, what would happen?
No, the speaker isn't moving. The cone would produce a pressure pulse that then propagates pursuant to the wave equation for sound in air, at the speed of sound. The only issue is if the wave is of sufficient pressure variation to reach zero pressure on the valleys, at which point there will be clipping of the valleys of the signal, which occurs at about 194 dB SPL.

Cheers,

Otto
Old 20th May 2012
  #22
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Quote:
Originally Posted by ofajen View Post
No, the speaker isn't moving. The cone would produce a pressure pulse that then propagates pursuant to the wave equation for sound in air, at the speed of sound. The only issue is if the wave is of sufficient pressure variation to reach zero pressure on the valleys, at which point there will be clipping of the valleys of the signal, which occurs at about 194 dB SPL.

Cheers,

Otto
Put another way, the distortion occurs when the backward pulse is so fast that the air cavitates.

Cheers,

Otto
Old 20th May 2012
  #23
Gear Guru
 
AllAboutTone's Avatar
 

Quote:
Originally Posted by Roboticus View Post
So in theory, a speaker that could produce a square wave that accelerates fast enough to break the sound barrier would sound like a cracked whip on buffer repeat. Now if I were to record the crack of a whip and put it through a beat repeater, what would happen?
I don't wanna hear it that's for sure.
Old 20th May 2012
  #24
Gear Nut
 

Quote:
Originally Posted by AllAboutTone View Post
I don't wanna hear it that's for sure.
I think you sir have just uttered the magic words for the driving purpose for someone to produce a whole new genre of music based off of this concept.
Old 20th May 2012
  #25
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matt thomas's Avatar
Quote:
Originally Posted by joeq View Post
about 5,400 mph - that's around Mach 35
Actually it's about mach 7..



matt
Old 20th May 2012
  #26
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Speakers mechanically make sound, and sound can't go faster than the speed of sound. You might be able to make an experiment if you got the speaker to move 675 miles an hour though. I don't think that speakers can make sounds that high pitched.... a sound so high in frequency that it moves faster than the air can move. And even if you did that, I'm not sure you'd get anything, much less a "sonic boom". Probably just silence.
Old 20th May 2012
  #27
Gear Guru
 

Quote:
Originally Posted by matt thomas View Post
Actually it's about mach 7..



matt
you are right

I think did something weird with the javascript Mach Calculator
Old 20th May 2012
  #28
Gear Head
 

Quote:
Originally Posted by Roboticus View Post
For example, if it could produce a transient quickly enough or produce a near perfect square wave? Would this make the speaker too good in a sense that it produces effects that would never translate to the home listening environment?
Nothing physical can respond instantaneously. This includes your ear, so even if such a speaker existed, your ear would only hear the harmonic content up to ~20kHz (and mine would only hear the content up to about 14kHz ... to many nights next to the snare drum ).
Old 20th May 2012
  #29
Registered User
It takes time to accelerate a mass. But what we could do is mount a speaker on a revolving arm, and slowly accelerate the arm up to the speed of sound. This would be an engineering challenge, so it doesn't fly to pieces. But now we could feed an audio signal into the speaker, and the velocity of the speaker cone would add to the velocity of the speaker itself. This would be one scary big Leslie speaker, exploiting the same Doppler effect. It should be possible to exceed the speed of sound with this rig ... No idea what would happen.
Old 20th May 2012
  #30
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Quote:
Originally Posted by Kiwi View Post
It takes time to accelerate a mass. But what we could do is mount a speaker on a revolving arm, and slowly accelerate the arm up to the speed of sound. This would be an engineering challenge, so it doesn't fly to pieces. But now we could feed an audio signal into the speaker, and the velocity of the speaker cone would add to the velocity of the speaker itself. This would be one scary big Leslie speaker, exploiting the same Doppler effect. It should be possible to exceed the speed of sound with this rig ... No idea what would happen.
Email it to Mythbusters. They would be the only guys off the top of my head willing to do something like that, just to see if it could be done.
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