I was wondering (not that is possible):
You build a sub with helium in it, the weight of helium is a factor 7 lighter then the air. So the speed of sound in helium is much slower. In fact if the speed is also a factor 7 slower then it is in the air then it should do ~47m/Sec.
That means that if you build a TLsub for about 30 Hz it would normally takes a tube of ~2,75meter, but with helium it should only take 0,39meter.
But because its helium and you want to keep the helium inside, you want to build a closed sub. And if you want to build a closed TL you must build it twice as long. But even then you get a sub thats only 0,78meter.
Just a theory... but is it true?
You build a sub with helium in it, the weight of helium is a factor 7 lighter then the air. So the speed of sound in helium is much slower. In fact if the speed is also a factor 7 slower then it is in the air then it should do ~47m/Sec.
That means that if you build a TLsub for about 30 Hz it would normally takes a tube of ~2,75meter, but with helium it should only take 0,39meter.
But because its helium and you want to keep the helium inside, you want to build a closed sub. And if you want to build a closed TL you must build it twice as long. But even then you get a sub thats only 0,78meter.
Just a theory... but is it true?
When you fill your lungs with helium and speak, you speak in a very high voice. Remember that your voice is given by resonant properties in your larynx, sinuses, etc as well as the frequency of vibration of your vocal chords.
This suggests to me, then, that the Fs of the enclosure will go *up* when filled with helium.
Just a guess, though. It's possible that there's some kind of frequency shift going on when the expelled helium meets regular air, I don't know enough physics to know for sure.
Wes
This suggests to me, then, that the Fs of the enclosure will go *up* when filled with helium.
Just a guess, though. It's possible that there's some kind of frequency shift going on when the expelled helium meets regular air, I don't know enough physics to know for sure.
Wes
I just looked on google and it turns out the speed of sound in helium is 970 m/s..
In argon it's 319 m/s, neon is 435 m/s.
In argon it's 319 m/s, neon is 435 m/s.
okay so with helium the sub gets even longer (that can't be good)
I could not find that with google (wich keyword did you use?)
so I have to look for a gas thats heavier...
but still the big question; would this work?
I could not find that with google (wich keyword did you use?)
so I have to look for a gas thats heavier...
but still the big question; would this work?
The speed of sound in sulfurhexafluoride would be about half that of the speed of sound in air. Due to it's inertness and price it would probably be the best choice.
Wkr Johan
Wkr Johan
you live with a billionth of a part of your air as sulphure hexafluoride. I bet it has a terribly bad odor! I would go for uranium hexafluoride. Much better smelling. go ahead, smell it.
If the sub were completely sealed(which it would HAVE to be for this idea to work) then you wouldnt be smelling what was inside. Take for instance a bottle of colonge, if the bottle is COMPLETELY sealed, can you smell colonge through it? Not unless some is on the outside
Id be more concerned with some kind of ignition (although it wouldnt be likely to happen if it was vacuumed then filled with helium)
You'd have to have a different method of sealing, id imagine - most glues are porous to a point (much like vinyl tubing is, but it doesnt 'leak' persay) so you'd have to have some kind of container inside the unit to stop it from leaking over time (unless you want to regas your sub... bahaha, classic)
You'd have to have a different method of sealing, id imagine - most glues are porous to a point (much like vinyl tubing is, but it doesnt 'leak' persay) so you'd have to have some kind of container inside the unit to stop it from leaking over time (unless you want to regas your sub... bahaha, classic)
2 ideas
1. the surround of your woofer leaks air, which makes it impossible to do this.
2. if you could stop the surround of your woofer from leaking air, a sort of nozzle sealed into the side of the box that has an adapter for attaching to a canister of compressed gas might be an easy way to put the gas in, but then you could never fill it completely with the desires gas,, just more and more.
also, has anyone thought about what pressurizing the air behind the woofer would do, (it the surround dind't leak air) i have a feeling that it would change something,
thanks for reading
1. the surround of your woofer leaks air, which makes it impossible to do this.
2. if you could stop the surround of your woofer from leaking air, a sort of nozzle sealed into the side of the box that has an adapter for attaching to a canister of compressed gas might be an easy way to put the gas in, but then you could never fill it completely with the desires gas,, just more and more.
also, has anyone thought about what pressurizing the air behind the woofer would do, (it the surround dind't leak air) i have a feeling that it would change something,
thanks for reading
You could put two nozzles on it. One for putting the air in and the other for letting the air inside out. Granted, it would take a LONG time to reach even 95% of the kind of gas you want, but it would work.
pressurizing the air behind the driver would cause the cone to move out and it would kill the driver's performance.
Rademakers said:
It is something like that, that Michael Dayton-Wright used in both his ESLs & his woofer boxes to give the boxes more apparent volume. (somewhere Nelson posted with the gas)
With Helium you'd need to build a much bigger box.
dave
Well, give it enough pressure and you would have a dome instead of a cone😀
If you pressurize the gas inside, you would have to do something to keep the voicecoil in the gap. Some kind of springloading maybe. It will stiffen the whole system and the resonant frequency goes up, and sensitivity goes down.
What about loosely filling a gastight thin bag with gas inside the box?
Then you could even have a BR or TL without thinking about gas leaks.
If you pressurize the gas inside, you would have to do something to keep the voicecoil in the gap. Some kind of springloading maybe. It will stiffen the whole system and the resonant frequency goes up, and sensitivity goes down.
What about loosely filling a gastight thin bag with gas inside the box?
Then you could even have a BR or TL without thinking about gas leaks.
i think we've got something here
If the speed of sound is 7:1 in helium:air
and if that means the box would have to be seven times bigger with helium in it.
Who can do the calculations on a very practical gas.
who can figure out what the ratio would be for something that makes sound travel slower
imagine the possibilitie's in a car audio invironment, just think.
When designing a driver, you want it to be sensitive, work in a small box, and handle lots of power. im no expert, but i've been told that you cant have all three. something had to give. as if it were some sort of a trade off between the three.
So if you eliminate the need of working in a small box, you would not need to make a tradeoff on box size, you could focus all your drivers potential in the other areas,
Think about combining this design theory in a driver with FEA(finite element analysis), the driver would be the single best driver in production.
and who better to make the driver then Eminence, They could do the whole thing
Just a thought,
Thanks
If the speed of sound is 7:1 in helium:air
and if that means the box would have to be seven times bigger with helium in it.
Who can do the calculations on a very practical gas.
who can figure out what the ratio would be for something that makes sound travel slower
imagine the possibilitie's in a car audio invironment, just think.
When designing a driver, you want it to be sensitive, work in a small box, and handle lots of power. im no expert, but i've been told that you cant have all three. something had to give. as if it were some sort of a trade off between the three.
So if you eliminate the need of working in a small box, you would not need to make a tradeoff on box size, you could focus all your drivers potential in the other areas,
Think about combining this design theory in a driver with FEA(finite element analysis), the driver would be the single best driver in production.
and who better to make the driver then Eminence, They could do the whole thing
Just a thought,
Thanks
Sulfurhexafluoride is oderless and inflammable, so no problems there (could have found that out yourself btw).
It is also a fairly large molecule so it wouldn't leak that much as air would. Some speakers would be unsuitable because of their surround or dustcap, however a rubber surround would be less sensitive for leakage.
SF6 is much heavier than air, so it would just sink to the bottom with the air floating on top of it. This way it will replace the air much the same as water would.
Even if it would form a mixture the effect would be very noticeable since the speed of sound in SF6 is much lower as the speed of sound in air.
Wkr Johan
It is also a fairly large molecule so it wouldn't leak that much as air would. Some speakers would be unsuitable because of their surround or dustcap, however a rubber surround would be less sensitive for leakage.
SF6 is much heavier than air, so it would just sink to the bottom with the air floating on top of it. This way it will replace the air much the same as water would.
Even if it would form a mixture the effect would be very noticeable since the speed of sound in SF6 is much lower as the speed of sound in air.
Wkr Johan
I dont think power handling was in there... I think it was low frequency extension that you were thinking of.
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