[fredk]

I was wandering through our plant today admiring our nice big round carboard garbage cans when it struck me they look a lot like sonotube. The are containers for bulk mig weld wire and measure 21.5" ID by about 3' tall.

I don't know how ridgid they are compared to sonotube, but I am wondering if they will do for playing around with different sizes and tunings.

Anybody else ever see these? What do you think?

 

[evilskillit]

Basically like a 50 gallon drum but made of cardboard with metal bands to hold the bottom on? I can't remember where I've seen those things but it does seem like I've seen them before. I don't remember them being terribly ridged. I think Sonotube is pretty hard stuff, similar in hardness to wood of the same thickness where as those cardboard drums can be flexed fairly easily I believe.

Like these?

 

[Mike P.]

At least swapping out a sub would be easy! :bigsmile:

 

[fredk]

Those are the ones. Without the metal bands they do push out of shape rather easily.

 

[evilskillit]

Yeah way too flimsy. Push on some sonotube some time.

 

[SteveCallas]

You can sit on a piece of sonotube that size and not cause any deformation.

 

[fredk]

That answers my question, thanks.

 

[evilskillit]

Would be pretty hilarious to see a sub in one of those tho. Something big with some serious power might just pop the other end right off when the bass hits. Would make a good youtube video if nothing else :whistling:

 

[StereoClarity]

I think you guys have the wrong idea about sonotube and why it's good for what we use it for. The great thing about sonotube is not the perceived strength from what you can feel if you tried to squish or sit on it. It's inherent strength properties from from its shape.

Remember, air has no "pressure points". It can distribute force equally on all sides of an enclosure. So imagine for a second, a cardboard tube from a roll of TP or paper towels. You could easily squish it with one hand. But can you plug one end and break it by blowing into it and pressurizing the tube? Not a chance; you'll fail.

The point is that the shape of a cylinder has no corners and so the force is distributed evenly which makes it VERY strong.

 

[evilskillit]

That is true, however would you really build a speaker out of a really big paper towel roll tube because thats sort of what those cardboard barrels are, they're fairly sturdy but I just wouldn't count on them to properly handle a high output sub, especially if you used it sealed for whatever reason.

 

[fredk]

Now that you put it that way evilskillit, its very tempting. :dumbcrazy: I never quite got enough of blowing stuff up as a kid.

 

[evilskillit]

It does sound like a lot of fun. I'd probably just use an M-80 tho. I would get nervous when trying to blow up things using an expensive subwoofer

 

[SteveCallas]

The point is that the shape of a cylinder has no corners and so the force is distributed evenly which makes it VERY strong.

Right, but you still need some strength from the walls themselves, otherwise you could dent the thing just by trying to move it.

 

[fredk]

...I would get nervous when trying to blow up things using an expensive subwoofer

Well, the driver would be mounted on the bottom attached to the base so it shouldn't go anywhere. What could possibly go wrong? :gulp:

 

[evilskillit]

What could possibly go wrong? :gulp:

Famous last words, heh. On the off chance that we wanted to get all Mythbusters and try this just for giggles I would make a solid anchored wooden frame, attach the woofer to that and then build the cardboard tube on top of that so that if it does pop the woofer doesn't possibly fall out and hit the floor. Also if you have to drive the speaker hard and then the thing pops you're pushing a bunch of power to a woofer that is suddenly playing free air, the voice coil might go careening right out of the gap. Other than those two things I can think of right off of the top of my head... you're right what could possibly go wrong. :devil:

 

[StereoClarity]

Right, but you still need some strength from the walls themselves, otherwise you could dent the thing just by trying to move it.

Yes but I think sonotube is strong enough that you don't have to really worry about that.

I'll be perfectly honest though and say that I was worried about the same thing once when I did my first build of this type. I erred on the side of caution and went with 12" PVC pipe. Yep, they make it that big you just have to go to a plumbing supply store to get it; and you have to buy the whole 20ft section of it too! The downside is that it's $200 for 20 feet and it's VERY heavy.

 

[ridecolby]

Wow that is a very interesting set you have there. Are those full range speakers for your LCR and is that a 12" in the 12" tube? Is there a build thread for the sub?

 

[SteveCallas]

Yes but I think sonotube is strong enough that you don't have to really worry about that.

Agreed, but we were talking about cardboard garbage cans. Those aren't nearly as strong as sonotube - they dent very easily.

 

[fredk]

Hmm... The Mal-X Trashcan. It does have a certain ring to it...

 

[evilskillit]

Heh, yes it would, let me find the resonant frequency for rubber maid and I can tell you exactly what ring it will have to it. :nerd: