Alright, let’s get crazy and build (in our mind) a state of the art sealed speaker cabinet and replace the internal air with other gas of other properties, for example Helium.
As sound waves travel differently through different mediums… what would you think the outcome would be?
As sound waves travel differently through different mediums… what would you think the outcome would be?
It would leak the expensive helium away in a few hours.😂
At least until some equilibrium was reached.
That said I guess the speed of sound is higher in helium (I think) so I guess the tuning would be different. Might make the cabinet appear larger.
At least until some equilibrium was reached.
That said I guess the speed of sound is higher in helium (I think) so I guess the tuning would be different. Might make the cabinet appear larger.
If you use Helium you will end up with a larger enclosure.
Dayton Wright used Sulphur HexaFloride in his XG-8 ESLs and later in the woofer enclosures for his more conventinal loudspeakers. It was a PITA if you had to fix them.
dave
Dayton Wright used Sulphur HexaFloride in his XG-8 ESLs and later in the woofer enclosures for his more conventinal loudspeakers. It was a PITA if you had to fix them.
dave
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Diffusion, until the internal air became normal air again.
I once tried to seal a woofer, so I could use it as a pump, in a sort of reed valve arrangement. No matter how much seal I put on the cone / suspension, I could not make a perfect leak-less seal. I quit the idea.
I imagine any ordinary driver will leak like mad. But you didnt say slightly pressurized cabinet, with constant flow replenishing...
I once tried to seal a woofer, so I could use it as a pump, in a sort of reed valve arrangement. No matter how much seal I put on the cone / suspension, I could not make a perfect leak-less seal. I quit the idea.
I imagine any ordinary driver will leak like mad. But you didnt say slightly pressurized cabinet, with constant flow replenishing...
Sulphur hexafluoride (6.17 kg/m3) is the stuff that people use to artificially make their voice lower (similar to helium making it higher).
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Smallest after the hydrogen molecule, of course.
Helium will diffuse faster out of a porous container, such as a balloon, than air will diffuse in. 🤓
I think that if you managed to keep the helium inside and if the box were not exceedingly large, it would hardly make any difference compared to air with the same pressure. Both are approximately ideal gases.
https://en.m.wikipedia.org/wiki/Ideal_gas_law
https://en.m.wikipedia.org/wiki/Ideal_gas_law
I considered this myself, but I think it simply raises the cone resonance frequency, reduces the resonance frequency for heavy gasses. Given the containment problems, not worth the trouble.
You are probably right. I was thinking about the spring-like behaviour of the air or helium, but it also contributes to the effective cone mass.
Hydrogen is the smallest atom, as a molecule helium is the smallest molecule because hydrogen is di-atomic. Hydrogen rarely if ever exists a a free atom. It’s H2.
Helium is used extensively as a leak detection gas for that exact reason for ultra high vacuum systems (electron microscopes, sputtering and CVD systems or cryogenic systems).
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I should mention that Dayton-Write had the gas in a plastic bag. In the case of the ESL, the elements were inside the bag, in the boxes it was a bag that filled the box.
dave
dave
After reading about SF6 it is apparently a very good high voltage dielectric material. Not a customer friendly design. Hope that it sounded good.
The XG8s were stad outs. I was mezmorized more than once with XG8 and stacked XG8, both driven by NAIM250.
The box speakers were OK. For the day.
dave
The box speakers were OK. For the day.
dave
Diatomic hydrogen diffuses faster than monoatomic helium because of its smaller molar mass.
Graham's law of diffusion applies:
RATE diatomic hydrogen / RATE monoatomic helium = √4 / √2 = 1.4 / 1