How to mount subwoofers on plexiglass?

[Eric111e 10+ year member]

Im going to be making my subwoofer box soon and i want the front panel to be plexiglass. I will be getting 3/4inch plexiglass. Im running 2 13W7's so i dont know exactly how i would mount the subs up. Will just bolting them to the plexi glass give them enough support? Or would it eventually crack the plexi from being under so much pressure and weight after a long time?

Also im trying to think of a good way to attach the plexi to fiberglass since my whole box is fiberglass. Any ideas?

Just to give you guys a heads up on my box plans. This is going in the back of a Explorer. The box is going to be made out of fiberglass and is going to go across the whole back. Im mounting 2 13W7's with a plexiglass front. Then all the inside sides of the box im going to get mirror plexiglass so you can see 3 different reflections of the subwoofers (back, and both sides)

Then ill make a nice little amp rack infront of the subs on the floor with plexiglass covering them and i will put fans in it to cool them down.

Click to read more...

 

[lrgnation 10+ year member]

i probably wouldnt mount my subs to plexi glass just because i have never personally seen it done with subs of that size. but it sounds liek an awesome idea. It really depends on how strong the plexi is, i would think it would need to be reinforced.

instead you could make a wood front. cut out a lot of the area and router down some and flush mount the plexi in that. so you will still have enough support. I guess it really depends on how thick the plexi that you want to mount the subs to is.

 

[unrated 10+ year member]

its really simple if u do it right, after u cut out the inner circleplace the sub in the proper mounting area, mark the screw holes, take out sub, drill out screw holes(do not screw into plexi it will crack), now u will half to make or get some1 to make a steel backplate, this reinforces the plexi and the screws and drill screw hols in it too, next you mount the sub on the plexi, next u take the steel circle backplate and put it on the inside of the plexi, then u get screw and nuts and washer and crank it up, now your sub and plexi are bullet proof, if you dont put a steel plate behing the plexi, and crank up the system the theres not enough reinforcement on the plexi and it will crack/shatter from the flexing

hope that helps

 

[ravendarat 10+ year member]

its really simple if u do it right, after u cut out the inner circleplace the sub in the proper mounting area, mark the screw holes, take out sub, drill out screw holes(do not screw into plexi it will crack), now u will half to make or get some1 to make a steel backplate, this reinforces the plexi and the screws and drill screw hols in it too, next you mount the sub on the plexi, next u take the steel circle backplate and put it on the inside of the plexi, then u get screw and nuts and washer and crank it up, now your sub and plexi are bullet proof, if you dont put a steel plate behing the plexi, and crank up the system the theres not enough reinforcement on the plexi and it will crack/shatter from the flexing
hope that helps

Exactly the way I do it. I do have a question though, with what you are describing to me, why not use MDF to make the box then install your mirrored plexi on the inside. It just seems to me that what you are doing would be better suited to have ridged flat surfaces like wood as opposed to fiberglass which is going to not be flat and make it very hard to attach mirrored plexi to. If your hooked on fiberglass and want to know how to attach plexi, I would make a MDF frame at the top, mabye 2 inches thick or so. Fiberglass to the trim ring then screw the Plexi to the wood ring.

 

[Decipha 10+ year member]

ever thought of lexan? its alot stronger and won't flex as much.

you should have a chat with bubbagumper6... I designed him a box with the same idea, a glassed front, and all mirrors in the rear and sides to reflect the subs

 

[amartin_72]

I smell bs.

 

[ravendarat 10+ year member]

I smell bs.

Why do you say that, its not that big of a job. I have done setups very similar to that, albiet with lesser subs, but still the install its self isnt that complex, except for the use of fiberglass instead of MDF which as I stated before I think is a mistake

 

[AlpineUser 10+ year member]

do you have the w7's yet??cause if you dont and you dont know the price of them you will be wasting ur time building the box because they are rediculously expensive

 

[Eric111e 10+ year member]

So my best bet would be to use MDF? This is definetly a box i want to do and no this isnt bs. I could get 1inch plexiglass also.

 

[truckstoy 10+ year member]

use lexan as stated above, alot stronger than regular plexiglas.

 

[djman37 5,000+ posts]

once again. here's the link to the DIY network HOW-TO.

http://www.diynetwork.com/diy/ab_parts_accessories/article/0,2021,DIY_13690_3607745,00.html

check out what gately audio does.

http://www.gatelyaudio.com/

 

[squeak12 10+ year member]

I wouldnt worry so much about how to mount subs to plexiglass, but how to attach mirrored plexiglass to fiberglass.

 

[helotaxi 5,000+ posts]

I wouldnt worry so much about how to mount subs to plexiglass, but how to attach mirrored plexiglass to fiberglass.

No kidding. If the inner surfaces are flat enough to mount mirrors to, they shouldn't be made out of fiberglass. It won't be nearly stiff enough to make a good box.

Lexan is a poor choice. Harder to work and more likely to crack. Also if you scratch it the piece is trash. Lexan is shatter resistant, but it cracks and sctarches rather easily.

Now as far as the original question goes, there are some good things in here but they neglected the most important thing when working plastic that is being used as a structural component. Any drilled holes must be perfectly smooth. All edges must be polished. Any rough spot on the edges or the drilled holes will focus stresses when it flexes (it won't flex much unless it is a very large area, but it will flex some.) and cause it to crack. If you have never worked in plastic, get someone who has to show you some of the tricks to drilling plastic and getting a smooth hole. Two of the keys are a very sharp bit and USE A DRILL PRESS. If the hole is just a little off from perpendicular to the surface, you will crack the plexi when you try to tighten the screws to hold everything together.

 

[ramos 5,000+ posts]

Did I miss the part where you said how large this acrylic panel is gonna be ? 3/4 plexi over a large panel is gonna flex like a mofo unsupported. Which means your gonna have to support it, curve it, or get thicker acrylic. But too mount subs you need to get holes just like helo said . Then bolt the sub in //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[ramos 5,000+ posts]

No kidding. If the inner surfaces are flat enough to mount mirrors to, they shouldn't be made out of fiberglass. It won't be nearly stiff enough to make a good box.

I agree flat surfaces should be made of wood, but for the first time I disagree ( with Mr. helo anyway //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif )on why.

Fiberglass can be reinforced to be made as stiff as wood. But why go to all the trouble and expense to do it ? Wood is so much cheaper, easier , and flat to begin with. Wouldn't make sense to go to all that trouble . //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif