Vacuum

Anybody knows anything about using vacuum to deal with acoustics? I mean, what would it be if you put a barrel with vacuum in, in corner of a room. Or put some acoustic "trap" with vacuum in, on walls. Or behind speakers. And similar things. Somebody in this forum discussed making vacuum in walls. There was a question about maintaining vacuum. I mean, you make vacuum before session, which should be alright until the end session -- Mario

Mario, I've never heard of a vacuum working as a bass trap. That doesn't make sense to me. Could you explain it better? Do you have a link to any evidence showing the response and ringing in a room before and after making a vacuum? --Ethan

Ethan Winer wrote:

Mario, I've never heard of a vacuum working as a bass trap. That doesn't make sense to me. Could you explain it better? Do you have a link to any evidence showing the response and ringing in a room before and after making a vacuum? --Ethan

Oh, sorry, this was just a question. I have no idea. I thought that maybe somebody here knows more. It is intriguing idea to me, and I'll try to learn more about this. Maybe someday I'll try something, myself. -- Mario

Mario, > It is intriguing idea to me < But that's not how acoustics works. :) All acoustic problems are caused by reflections, so the correct approach is to target the surfaces that reflect to instead make them absorb. A vacuum seems unlikley to help with that. It's not like you can suck the offending waves out of the air! --Ethan

Mario, A vacuum is useful in construction to improve sound isolation. Since sound cannot travel through a vacuum, using an evacuated space in lieu of an airspace between two walls, say, would be a very effective isolation measure. It is a rather difficult thing to do, however, and can get expensive.

Thanks, both of you. I'll read some more, and then see how my ideas will develop. I am thinking of putting sound deflectors, and sound barriers, and that way manage sound pressure throughout the room. That way I could possibly create parts of room that have different level of sound pressure, and so drop level of sound pressure around listening position. -- Mario

Oh, yes. I was thinking to deflect sound towards vacuum. -- Mario

I can hardly imagine one application in a studio where a vacuum could be realistic. The over pressure outside such an application should cause such an application to implode, unless strenghtened to a level that it becomes unreal or that flanking should destroy the usefulness of the application. Hence a vacuum is fun in a lab underneath a glass tank getting it's strength by its shape to demonstrate the phenomenon, and maybe few very specific technical applications. I can't imagine any of them related to studio use.

Eric_Desart wrote:

I can hardly imagine one application in a studio where a vacuum could be realistic. The over pressure outside such an application should cause such an application to implode, unless stenghtened to a level that it becomes unreal or that flanking should destroy the usefulness of the application. Hence a vacuum is fun in a lab underneath a glass tank getting it's strength by its shape to demonstrate the phenomenon, and maybe few very specific technical applications. I can't imagine any of them related to studio use.

Thanks. Yes, I was thinking about in what way flanking would affect all this, and trying to maximise good sides, and minimise bad sides. But, I don't know much about it, anyway. I just asked for your oppinion, just to see what can I expect from this idea. -- Mario

Mario, A simple calculation learns that a perfect vacuum causes the pressure on such an application to be 1 Atm or 101.325 kPa = 10332 kgf/m2 = 14.7 psi Try to make a practical application resisting those forces, or even part of it for less perfect vacuums. And then take into account that both sides must remain perfect decoupled before it has sense to use the principle for TL purposes. And then you still must be able to maintain that vacuum.

My "day" job is in an industrial rare metals plant; I work with all sorts of process control hard and software, and we melt metal ingots in a vacuum arc and vacuum plasma arc furnace (several of each) - these chambers are only typically 3 feet in diameter, and up to 20 feet long - in order to maintain a tight vacuum, the vessel is made of rib-reinforced 1/2" to 1" thick steel, and three different designs of vacuum pumps are used in tandem to maintain a vacuum of typically 1 to 10 microns/Hg (atmosphere is typically 760 Torr, or millimeters Hg) - our vessels are constantly leak-checked in order to maintain an acceptable leak rate of less than 5 microns in 5 minutes, some even less than that. This process is ungodly expensive, the pumps are noisy and large, and I can see (as Eric already mentioned) no practical way to incorporate this into even a "George Massenburg" type studio, much less one of practical cost... Steve

[ I can see (as Eric already mentioned) no practical way to incorporate this into even a "George Massenburg" type studio, much less one of practical cost... Steve ] I use a vacum at the studio all the time. I thihk it's a Eureka. It was only about $100 and it works pretty good. :lol:

Ok folks, thanks. It was an interesting conversation. I learnt some things, :? . -- Mario

I use a vacum at the studio all the time. I thihk it's a Eureka. It was only about $100 and it works pretty good. "Stuntbutt" - name seems to fit so far :lol: I think the main reason yours works better than the systems I described may be the beater bar/power brush attachment... :wink: Steve