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Discussion Starter · #1 ·
I just finished building my hushbox for a CRT. Can any recommend what I should use to insulate it? There's so many options it's hard figure out what I need. The stuff is expensive, so I can't really afford to experiment.


I made it w/ a pine 1x2 frame (all glued) and 1/8" masonite, w/ all the gaps on the inside caulked w/ silicoln and all the gaps on the outside filled in w/ joint compound. It's an open design box, so there will be a vent for air intake in the front where the lenses are. I have a good 2" extra room for insulation.


I was thinking of three layers.


1) 1/8" vinyl barrier

2) 1" of abosorbing foam (there's so many different kinds I'm lost on that one)

3) Eggcrate foam.
 

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Lifter,


I build a CRT hushbox that's close to what you've done (glued & screwed 1x2" pine frame covered in 1/8" hardboard and sealed). For sound deadening, I used 3 layers of 5/8" acoustic compressed fiberglass ceiling tile from Home Depot (basically the most expensive ceiling tiles they had).


This whole design was based on one posted here by Guy Kuo a few years ago. I'm happy with the results!


Click on the 2nd link in my sig for some photos or follow this link:

http://gallery.avsforum.com/showphot...t=1&thecat=500




Kal
 

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Discussion Starter · #4 ·
Thanks. You think ceiling tiles are better than a vinyl barrier? I'll look into it.


EDIT: BTW I forgot, your photos in an old thread are the only reason I was able to find any strut hangers in my area (nobody knew what they were called).
 

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Lifter: I'm not sure what you mean by "vinyl barrier" - do you mean really thin vapour barrier used on the outside walls of houses? If yes, I don't think that would stop any sound at all since it's essentially like very thick Saran wrap.


Kal
 

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Discussion Starter · #6 ·
There's a document on the web called "Acoustics 101", put out by Auralex, which is where I recently learned all I know about this stuff. I'm certainly no expert, but it's a great read and here's what I learned.


Vinyl barrier is very common and an important part of sound isolation. It is a dense sheet of condensed vinyl, usually 1 lb. per square foot and 1/8" thick. I installed this stuff in my car years ago called Dynamat. It was essentially the same thing. Solid, dense matter is what actually blocks sound and prevents it from transmitting through the wall or whatever. Just like a concrete wall. However, by itself it's no good because sound bounces off it easily and without an airtight box it's almost worthless by itself. Mineral fiber, such as what those ceiling tiles you and Guy used is meant to absorb sound, but cannot block it and can't absorb all of it. However, it is very efficient for high frequencies. So in the case of a hush box, it might be all that's needed.


Think of it like this way. You've got a leak in your roof and water is dripping down on your carpet and will get ruined if you don't stop it. If you put down a piece of plastic, it will block the water prevent the water directly getting to the carpet, but the watter will splatter and run off. If you just put a towel down, it will absorb most of it and help but will soon get damp and the carpet will still get wet. The ideal method would be to put down a piece of plastic and then put a towel on top of that. Make sense?


Anyways, I have a semi-elaborate plan. I ordered some 2" mineral fiber (basically, the same thing as those ceiling tiles but without the facing). I'll try it out and see if it's enough. If not, I'm going to line the inside w/ .5 lb vinyl barrier (can't be too heavy) and put the fiber on top of it. Then, if that's still not enough, I'll put some egg-crate foam on top of the fiber.
 

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Ah yes! I'm familiar with Dynamat. Your idea of putting a layer of something like that in first, then putting a couple of layers of ceiling tile in is certainly a good one.


I agree that half the battle is trying to absorb the soound that bounces around. If you have a completely sealed hushbox then a thin layer of very dense material would probably be enough.


Good luck! Let us know how it works out!


Kal
 
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