glass box build feedback please

[sexy 10+ year member]

Hope some experienced competitors see this post and can give me some feedback. I am building a new box for 2011 season 11ply birch 4 layers thick at minimum heavy gauge square steel tube caged on the outside. What I was wanting feedback on is the use of glass on the inside. Automotive grade safety glass bonded to the birch with body panel adhesive or ¾” polycarbonate instead of glass. Have any of you tried this or know of someone who has done the insides with glass? I wont be using the glass on the sub wall itself because of the weight of the subs. Box will be tuned @70hz final displacement will be between 15/16 cube wont know until that until I get it on the term-LAB I am building 16 cube to start then reducing internals until I get a peak on the meter.

Thanks for the feedback in advance. //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

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[Ge_off_me 5,000+ posts]

Sounds cool!

 

[sexy 10+ year member]

thank you very much

 

[keep_hope_alive Premium Member]

what is the area you expect for the glass (sq. ft.) relative to the area of the wall the glass will be on? is this for viewing of the subs from the back of the box or another purpose? got a sketch of what you are planning. the window may increase losses if not done just right - seams and seals are failure points.

 

[snoopdan 5,000+ posts]

You'll have bonding issues with adhesives. I'd stick to plexi.

70 hz? this sounds like one fucked up burp box.

 

[SuperJay 10+ year member]

Since you're really only asking about the glass that's what I'll address.

you're going to have 44 layers of laminated wood (about 4 inches), and only 3/4" of brittle acrylic or PC. with 15ft^3 of airspace I can only assume you'll be using multiple large diameter subs. This means LOTS of pressure and flex. The enclosure walls will flex differently than the PC will, so you'll have to overlap a lot more than you'd think...maybe 3 inches. double rows of pass through bolts and enough silicone to float your house through the next Katrina.

I think, to be safe, you'll want to have 2 layers of 3/4" PC sandwiched between the inner and out layer of birch.

 

[helotaxi 5,000+ posts]

I don't think he's talking about a window but rather LINING the box with glass. Not sure what benefit he's expecting or seeking with that.

 

[brian84corvette 10+ year member]

why not line the box with sheet metal. ? it would be just as dense as the glass would - and you wouldnot worry aobut it cracking

 

[helotaxi 5,000+ posts]

The sheet metal would not add any rigidity at all which I would assume is what he's going for. That said unless he used some thick glass, it wouldn't do anything either.

 

[Phoenix Risen 10+ year member]

tuning high is a puzzy way to try to get loud, but thats just me,

 

[brian84corvette 10+ year member]

The sheet metal would not add any rigidity at all which I would assume is what he's going for. That said unless he used some thick glass, it wouldn't do anything either.

o I was figuring that he might of thought the wood structure could act like a sound absorber since it is not as dense as glass

possibly the same thinking would be that the sound wave would reflect off the glass with less of the sound absorbed ?

kind of maby making the most of what is there to be had ? or would simply coating the entire inside of the box with a layer of fiberglass do the same thing ?

 

[SuperJay 10+ year member]

I don't think he's talking about a window but rather LINING the box with glass. Not sure what benefit he's expecting or seeking with that.

then why did he talk about polycarbonate? read more, talk less

 

[SuperJay 10+ year member]

and usually enclosures are lined with RESIN not GLASS to help seal the pores because most people don't understand that the enclosure doesn't resonate as well if it doesn't breathe...

 

[keep_hope_alive Premium Member]

and usually enclosures are lined with RESIN not GLASS to help seal the pores because most people don't understand that the enclosure doesn't resonate as well if it doesn't breathe...

that's correct Jay.

from the title i assumed resin and fiberglass on the inside. then i thought a window from the post... we need the OP to clear this up so the replies are useful.

 

[97maxima 10+ year member]

I def think the glass is for the smooth interior of the wall. I imagine if he waxes it he will gain a few 10ths