posted
iam just wondering, what happens when we hit the max slp that the atmospheric presure will allow? will a sonic boom or somthing occure from this? will the soundwave just start overlaping causing a ripple in the sound waves? i guess iam just verry curious as to what is gona happen once this level have been reached, any responces? thankx
Chris
-------------------- Founder of team NOIZE FACTORY Member of Team Gates Beliver of ABC boxes Clarion DXZ555MP Head Unit 1 HUGE ABC box Dissapointing 148.7 AC190 Mic Posts: 571 | From: Sudbury, ONT, Canada | Registered: Jan 2001
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well, since sound is only bursts of compressed air, theoretically, the hydrogen, methane, etc. could ignite. so, loud gets louder. Posts: 119 | From: Marysville Michigan | Registered: Dec 2002
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From my limited knowledge...I don't think there would be a sonic boom. That is a whole different thing that has to do with speed, not volume. Also, why do you think that the various flammable gases would ignite??
-------------------- 1994 Ford F-250 7.3L Powerstroke Diesel Super Cab Long Bed 33" Mud Terrains Yeah, it's big, and yeah, it's got balls. Posts: 876 | From: Decatur, IN | Registered: Apr 2002
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When SPL becomes such that the rarefaction phase involves 14psi of pressure, you're talking about trying to create a perfect vacuum.. Which is obviously impossible for a given amount of gas, no?
Therefore, the only way is UP, to get a maximum variation which involves as much rarefaction as possible and then as much pressure as possible.
Ok, so numero dos.. Air doesn't respond quite the same at very high pressures as it does at lower pressures.. Chances are 28psi or more won't liquefy air (ha ha...) however as the pressure differential gets higher the displacement will go up exponentially as well as the quickness of energy loss..
And, third.. Do you have any idea how much pressure 15 PSI is? In order to make a speaker cone that can move back and forth 40-70 times a second, its gotta have enough motor to move it.. To make a cone strong enough to wistand a 15PSI differential over the whole radiating region of the cone, we're talking serious cone mass here.. And that means exponentially stronger motors.
Can you think of one?
Flame transducers maybe...
However, air impedance matching (horn loading) is the best bet, but that has frequency limitations due to size, in a car..
ShadowStar
-------------------- You can't build a reputation for what you're GOING to do.. But you can build one for TALKING about it!
It's all about knowledge, love and respect. Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
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With the sub creating a constand push and pull of 15psi that will create a perfect vacume as stated above. During the state of vacume, Im guessing there would be no noise what so ever. At least IN the vacumes area. But befor that, the sound and pressure would be so great tht the whole works would probably just blow off
-------------------- - Posts: 12465 | From: BC, Canada soon CA, USA | Registered: Oct 2001
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if the car and box hold up to the sound blast then the subs will most likely implode?
-------------------- 2006 IDBL 2ND PLACE WORLD FINALS 2008 World Records TBA LiL Scrappy The Louddest Honda 600 in The World! www.quadaudio.net Posts: 1901 | From: Palm Springs,CA | Registered: May 2002
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posted
Thank you Shadowstar for giving the subject serious consideration. I will now submit my thoughts for your consideration.
Most of us know that the supposed spl limit is 194 dB. Well, I know that's only true if you're still competing in SQ, because 194 dB is simply the point where the negative cycle of the wave will peak at 0 psi. We can't go any lower, but we can go much higher. There's no real limit as to how high we can go. 194 dB is the limit of sinusoidal tones. Beyond that you're guaranteed to have distortion with no way to compensate.
So, what do I think will happen when we reach the max spl of our atmosphere. Umm, nothing, there is no maximum. I honestly think it will be very long time before we reach 190 dB using the standard speaker transducer.
Posts: 768 | From: Ottawa, On, Canada | Registered: May 2000
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Just my 3 cents but it really wasn't that long ago when a 150 db was considered near impossible
Posts: 63 | From: Wa | Registered: Apr 2002
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quote:Originally posted by emu: Thank you Shadowstar for giving the subject serious consideration. I will now submit my thoughts for your consideration.
Most of us know that the supposed spl limit is 194 dB. Well, I know that's only true if you're still competing in SQ, because 194 dB is simply the point where the negative cycle of the wave will peak at 0 psi. We can't go any lower, but we can go much higher. There's no real limit as to how high we can go. 194 dB is the limit of sinusoidal tones. Beyond that you're guaranteed to have distortion with no way to compensate.
So, what do I think will happen when we reach the max spl of our atmosphere. Umm, nothing, there is no maximum. I honestly think it will be very long time before we reach 190 dB using the standard speaker transducer.
As per me earlier: "When SPL becomes such that the rarefaction phase involves 14psi of pressure, you're talking about trying to create a perfect vacuum.. Which is obviously impossible for a given amount of gas, no?
Therefore, the only way is UP, to get a maximum variation which involves as much rarefaction as possible and then as much pressure as possible. "
I was addressing your very point here: IE a perfect vacuum is impossible, but the maximum variation overall is the SPL so as much rarefaction as possible followed by as much pressure as possible..
However, if you think in terms of the phase change of a substance under extreme pressure at room temperature, I'm sure we can come up with a suitable REAL limit for our actual gaseous atmosphere.
ShadowStar
-------------------- You can't build a reputation for what you're GOING to do.. But you can build one for TALKING about it!
It's all about knowledge, love and respect. Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
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It'll be an event of biblical proportions! Fire and brimstone raining down from the sky, 40 days of darkness, Earthquakes, floods, Cats and dogs living together, mass hysteria!
(Yeah, so I'm a wiseass... and a geek. 2 Cool points to anyone who can ID the quote)
-------------------- I'm so happy, Cuz today I found my friends, They're in my head. Posts: 130 | From: Melbourne, Australia | Registered: Jun 2002
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posted
food for tought Decibel Review This same process is used for the decibel scale, with the same base (base 10):
dB == 20log(p1/p0)
where p1 is the air pressure amplitude of the sound we are interested in, and p0 is the air pressure amplitude of the comparison sound dB tells us how intense one sound (p1) is relative to another (p0). If we're simply asked how intense a sound is (and not given a value for p0), then we're calculating dBspl -- this is the intensity of a sound relative to the least intens e sound we can hear. For these problems, p0 = 20 micropascals (the smallest sound pressure level we can hear).
Here is an example:
What is the intensity of a sound with air pressure of 20,000 micropascals?
So the sound would have an intensity of 40 dBspl. Now let's see how much more intsense 60dBspl is than 40dBspl.
In this case, we are no longer using 20 micropascals as our standard. Instead, we'll use one air pressure amplitude (2000 micropascals) as the standard against which we want to compare another air pressure amplitude (20,000 micropascals).
This means that 60dBspl is 20dB more intense than 40dBspl. (you can see that this is the same as 60 - 40....) Here's one last example:
What is the intensity of a sound with air pressure of 20 micropascals?
(The "trick" to this problem is to remember that a number raised to the 0th power is 1) 20log(p1/p0) = 20log(20/20) = 20log(1) = 20(0) = 0
So, a sound of 20 micropascals would have an intensity of 0 dBspl. This makes sense! If there is no difference between the air pressures of the two sounds, then the two sounds will have the same intensity -- the intensity of the comparison sound r elative to the standard sound will be zero.
14psi converted to pascals =96551.724pascals, now convert that to micro pascals and its 96.551
anyone see what iam getting at?? please feel free to correct me if iam wrong, iam just curious as how to break the db berrior that has been set.
Who would of known math and physics back in hight school would come in handy with my passtime?
Chris
-------------------- Founder of team NOIZE FACTORY Member of Team Gates Beliver of ABC boxes Clarion DXZ555MP Head Unit 1 HUGE ABC box Dissapointing 148.7 AC190 Mic Posts: 571 | From: Sudbury, ONT, Canada | Registered: Jan 2001
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posted
They said the highest is sumthin like a 194.But if you think about it IN the boxes of some of these 170+db set ups there right in that area.Id imagine if you could step in that box at that time of spl the atmosphere would just be distorted.
quote:Originally posted by trickrichie: They said the highest is sumthin like a 194.But if you think about it IN the boxes of some of these 170+db set ups there right in that area.
Nope, it's often actually louder in front of the box in extreme vehicles. In some vehicles, the cabin is smaller than the box, so the cabin is actually the box...
I think 180 dB will be broken this year(Come on Team BS you can do it ), but over 190 dB will be a LOT harder, almost impossible, at least with the current dB drag rules.
-------------------- My system right now: A Sony HU and Focal Access 5.25" front system Posts: 546 | From: Vasa, Finland | Registered: Nov 1999
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Does the current dB drag rules only permit a conventional woofer (moving coil attached to cone...)? I mean.. I know that to be legal we need to use stuff that are availlable in ,arket or something like this.. right?.. now if i start my own compagny making driver that use ON and OFF valve that pulse compressed air from air tank (like High spl siren using perfored rotating disk in front of air blast) does i will be legal if i use this principe to replace wooder in my car to do spl?
-------------------- Street A "not legal but not outlaw!" Score in my integra: -152.34 dB 51Hz TL sensor -157,1dB 51Hz AC mic
2005-2006 Street A Champion in Quebec province!
CRAZY TESTs: ||||||THE ONLY 6.5" TO SCORE 168.9dB(TL)OUTLAW IN THE WORLD with 6 Watts.|||||| -Crazy 5.25 Bose sub 1.1cu box: 138.0dB TL mic 55Hz with ONLY 100W ! ---------------------------------- www.teamxmax.com Posts: 643 | From: Quebec city | Registered: Mar 2000
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And here I thought I had the masterplan. A 30 megaton H-bomb should hit around 230 at the dash, right before it disintegrates.
Posts: 768 | From: Ottawa, On, Canada | Registered: May 2000
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You i have seen in some references of how loud different things are, like they say a space shuttle launch is 180 db. How can they read that? Where do they place the mic without it disintegrating?
Posts: 62 | From: Big D, Texas | Registered: Nov 2002
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