# All metal speaker box



## Drewcantrell85

I have been into stereos since I was a teenager. Whenever I became a welder I had this idea to make an all metal speaker Box. Everybody gave me dumb looks every time I told someone I was gonna build one. I finally been able to make my idea come full circle. I think it works pretty well. It's a twin wall pressurize speakerbox I have about 15PSI in a right now. It's more a proof of concept I'd like to move on to Maybe 4th order Box with a 18" solo x. I have a video of it working but it won't let me load it. Just putting it on here to see if anyone has done anything like this and what you guys think.


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## DC/Hertz

I can't imagine that not resonating something terrible. That's pretty thin sheets.


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## Drewcantrell85

It's twin wall with 15 psi. The walls are solid they give a little when it really gets to hitting. But I can put more pressure between the walls.


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## Drewcantrell85

I was able to get the subs sealed tight with a gasket. And it hits pretty clean no box metal vibration just my vehicle. I have a video of it play bit I can't get it on here.


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## 82cj8

I built a sub enclosure out of my grand cherokee spare tire wheel.Left the tire on it so it looked bone stock in the back.It was .70 cuft with a Diamond Audio m6 sub.It sounded great but it was better in 1cuft.I drilled and tapped the mounting holes and i used 3/16" plate i think.It was solid.I work with metal daily and its easier for me to deal with than wood but the next box will be wood.


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## Drewcantrell85

I never thought of a tire for am enclosure. I just figure since my box has pressurized wall separate from the sub air space I can add pressure according to the sub. Low pressure for smaller sub and higher for the high all. And the box will literally last forever.


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## Justin Zazzi

Where is the pressure at? I haven't seen such a thing before. How did you come up with the design?


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## I800C0LLECT

Air pressure to reinforce a box is a neat idea


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## Drewcantrell85

It's basically a box within a box and the walls are 16ga 316 as. I used nipple and valve with a psi gauge to put air between the walls. I use compressed air. I've been kicking the idea around for 8 or 9 yrs. I believe fine tuned it can have marine audio applications. And extreme completion where bigger large sub can be used. Also tons of different metals to choose. I went with 316ss but there is aluminum and titanium would work. As long as it not magnetic.


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## Drewcantrell85

I wish I could post the video of it in action.


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## OCD66

Made this about 10 years ago. 3/16" plate tig welded. 1983 Toyota pickup. Goes through the cab about 2 inches. Solid.


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## Drewcantrell85

Looks good I like when it looks clean.


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## OCD66

On a side note, I've built pressure vessels. 15psi on 1 square foot is exerting 2160 pounds of force trying to blow that thing apart. Things can go really bad in an instant. The safer way is to fill with water and then pressure test. Much less stored energy.


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## Drewcantrell85

Im a pressure vessel code welder for a living. If it blows with air no mess. Also with water if it leaks the you have to put water back in. The way it is now any compressed air hose will work. And the 316ss 16ga tensile strength is around 62,000 psi so I'm far from the limits of the weld and material.


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## Drewcantrell85

I've been playing it in my truck for about a month on 15 psi. No problems no leaks. Other than the 1 to 2 psi fluctuation because of the cab of the truck cooling and heating I haven't had to put any more air in it since the initial fill.


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## OCD66

Cool. Sounds like you're good to go.


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## Drewcantrell85

https://youtu.be/Uc3LHE7PQKg this should be the video of it in my truck playing.


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## Jscoyne2

Ive seen metal boxes completely covered in deadener on the inside. Didn't resonate at all.


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## Drewcantrell85

This one has herculiner on the inside and out.


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## Drewcantrell85

The box weighed 250lbs without subs so weight was near a 3/4 msg with double wall supports.


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## Holmz

Drewcantrell85 said:


> Im a pressure vessel code welder for a living. If it blows with air no mess. Also with water if it leaks the you have to put water back in. The way it is now any compressed air hose will work. And the 316ss 16ga tensile strength is around 62,000 psi so I'm far from the limits of the weld and material.


I doubt you are that far away, as some of that strength is not tensile strength, but more like shear strength. But it would be easy enough to test it to failure. on a smaller mockup.

I do like your idea though.
One could also use some rivets and L shaped doublers, and some absorber between the doublers and the sheets would work wonders.

Personally I would not choose titanium. For a water tank, fuel tank, or an airplane or racecar it cannot be beat, but for holding a sub it seems overly decadent.
(And I have welded ti, although somewhat poorly, but OK for an amateur.)

Another method would be stand-offs every 3-4 inches tying the sides together... Like a threaded rod inside a tube with the sheets on the ends like washers. That would not be as elegant, and the back cannot be bolted to the speaker cone.

I like the concept a lot, and I can see where there could be a marine case that demands it.


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## Drewcantrell85

I tried to stay simple as possible everything is welded no threads no supports. The only thing I did which you can see in my pic is I drilled hole in the walls and used welding rods to connect the inner and outer wall so the walls wouldn't balloon when it inflated. But as far as tensile strength is actually more than I thought so even at 16 ga I'm am way under the capabilities of the metal. Here's link to tensile strength chart of what I am talking about.www.americanmachinetools.com/tensile_strength.htm


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## GEM592

Drewcantrell85 said:


> https://youtu.be/Uc3LHE7PQKg this should be the video of it in my truck playing.


lol pump that thing up until the needle stops wiggling!


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## Drewcantrell85

I think closer to 20 psi will do it


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## GEM592

Does it sound better? Very interesting stuff good job.


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## Drewcantrell85

It's hits pretty clean and loud I still need to turn the amp up I have everything turned down-right now just to be safe. As I get a feel for what the Box can do I'm slowly turning things up and getting things dialed in. Thank you


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## gumbeelee

Drewcantrell85 said:


> The box weighed 250lbs without subs so weight was near a 3/4 msg with double wall supports.




Geeeezzzz!!!!! That bastard is heavy, but that still is one ****ing cool ass box!!


Sent from my iPad using Tapatalk


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## Markous

Cool idea man! 

I'm a pipefitter by trade and this same idea has entered my mind a few times over the years, my idea was a slightly different design of having a metal cage covered with sheet instead of a double wall.

I like your idea of pressurizing it to one Bar and immediately it makes me wonder how it would react to having negative pressure (vacuum) applied to it.

Thanks for sharing


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