For building HUGE cabinets....

[Modmark]

and if weight becomes a concern...

How about foam core construction method.

Sonotube sub-woofers come to mind. Cut the tube into two pieces then cut the second tube to reduce the diameter. Mix up some Urethane foam and pour between the tubes.

This method works very well for boats. The surface stress vectors on the interior and exterior surfaces tend to be 180 out of phase while crashing thru a big wave. And this causes stress fractures in the fiberglass. The foam isolates the surface stress forces.

Just a thought, did I mention we have lake effect snow warnings in my neck of the woods and I miss summer already?

A source for Urethane foam, ..

http://www.uscomposites.com/foam.html

And FYI concerning Sonatubes, if you want to harden the exterior cardboard, UScomposites sells a general purpose polyester resin for $25/gallon. This include the hardener.

Oh dear, Watertown may get 15" of snow. I wish may nickname was MiamiMark.....

[bking]

I used an 8" diameter tube inside a 10" diameter. Used wood slats as spacers to keep the 8" tube centered, and filled the voids with urethane. Made for a strong, inert, and lightweight cabinet.

[davepellegrene]

I used a similar method buildind my Rock It speakers. A cabinet inside a cabinet with foam between. build pics at my link below in my signature. Made for some very dead/ heavy cabinets. Probably would sink too. : )
Dave
I'd post the link but I'm a dumb guy trying to master my new smart phone. I feel like I'm typing with my elbows.

[greywarden]

I still have a flip phone haha... I think I'm going to get a new phone when I go home for xmas, though...

Dragonplate... It's rediculously expensive. Carbonfiber-Birch sandwich.

[Modmark]

Thanks for the replies, I assumes you guys were happy with the result of using foam core construction methods.

On my wish list is a 15" ported subwoofer which MAY require a 7 cu ft cabinet. That is one heavy cabinet if made out of 3/4" MDF.

Of course the real challenge is convincing my wife that a 7 cu ft subwoofer cabinet would look great in the family room but that another topic.

So for a down firing design, I am toying with the idea of 3/4" mdf for the bottom and top. Then use 1/2" or even 3/8" plywood for the exterior sides and luann (1/4") for the interior wall. And foam in the middle.

And any help with successful negotiation methods with your spouse's would be much appreciated :-)

[arlis_1957@yahoo.com]

make two and paint them like roman columns.:D

[Modmark]

make two and paint them like roman columns.:D

That's actually my idea, two large bases with a pair of Nat P's on top. My inspiration is from the 1940's theaters with some elaborate trim work which would match the style of current trim in our older home.

My wife did issue a contract for the construction of an entertainment center. Unfortunately her idea is a standard shelving unit with our current Klipsch Quintet's buried inside a shelf and put the sub woofer in the basement.

Now what would Tim Taylor do?

[Starkiller4299]

So, I love the foam core idea, but if the goal is a large subwoofer, resilient to resonances, doesn't the sonosub already accomplish that without the foam? Sure the foam variety could probably take a nice beating, but the whole point of the sonosub is that it, by it's circular enclosure, is already highly resistant to pressure changes.

Just playing devil's advocate. Food for thought :p.

[Modmark]

So, but if the goal is a large subwoofer, resilient to resonances, doesn't the sonosub already accomplish that without the foam?

Just playing devil's advocate. Food for thought :p.

Good point, the foam core could be an overkill.

On the other hand, the tube is just a piece of cardboard and will hold up over the test of time ie: 10-20 years?

[OlderMongrel]

There are actually three different sizes of 12". Huh? :confused: Here's how it works...

I've been playing around with 8" and 12" tubes. Both brands I've seen locally (Quick-Tube, Ashgrove) actually come in "sub-sizes". What I mean is that there are, eg, three versions of the 12" that actually measure about 11.5, 12, and 12.5" in diameter. They are stacked on the shelves in threes packed inside each other. This must be to facilitate shipping and storage. So, one option would be to get a big and small 12" and fill in the gap for strength and stiffness.

I don't know if this applies to the larger sizes, probably not.

John

[greywarden]

Or use all 3 and have 2 foam walls. that'd alot stiffer.

[LouC]

I'd post the link but I'm a dumb guy trying to master my new smart phone. I feel like I'm typing with my elbows.

I write code for money. When I bought a phone I chose the one with the biggest buttons! :D

[Pete Schumacher ®]

Is that you on the left Lou?

http://2.bp.blogspot.com/_6q-f-zD4xPY/TVJR6LXFMMI/AAAAAAAAamQ/TahdnFLY4Yw/s1600/Jitterbug.jpg