[elvisjer]

Hello everyone! I'm working on a project to test the vibration absorption characteristics of some materials for an abstract architectural project, but also realized I may be able to gain some insight and numbers on the sound deadeners we use here as well. Im an interior architecture student and we are going to be testing the stability of some wall sconces and other products when extreme vibration is applied by sound such as at large clubs and I have been nominated to construct the device to test it with. I would have posted this under the "off topic" section except im going to test the sound deadener's ability to reduce vibration as well, but that's not really the main topic (yet).

Ok so here is my idea, do you see any fatal flaws?

-- Make totally sealed enclosure and use a rubber membrane in which a pole is attached to, then attach a metal plate to this pole on which the products will be attached onto. --

 

[05_sprcrw]

I would be a little worried about the sides of the rectangle binding inside the box.

 

[JSlabotsky]

A more accurate simulation might be accomplished by replacing the piston arrangement (although it is clever) with a simple drywall panel across what is the top of the enclosure in your illustration. But during tests I would orient the cabinet so the drywall is on the side. Then you could mount sconces and other fixtures to it just like in the real world. And if you destroy the piece of drywall it's simple enough to attach a new one. I would also make it a point to keep the open span the same width as between wall studs - 16"-24" depending on building construction.

 

[elvisjer]

Awesome, thanks for the info so far guys! What do you mean by, "the sides of the rectangle binding inside the box" ?

 

[05_sprcrw]

you would have to have a pretty close fit on that piston for it to work properly and it would be pretty tough to keep the wood from wanting to bind. If it got a little out of alignment it would probably bind up and then skew your results.

 

[elvisjer]

That's a great point. I'll be running the piston through a bearing in the top of the box and now am thinking the piston should have a guide sleeve inside as well. I'm probably going to make one side out of polycarbonate so I can watch what's going on and see if there are any problems.

 

[JSlabotsky]

What about putting a strip of felt or something along the edge of the piston? If the interior of the box were nice and smooth - either finely sanded or with a light coat of finish - it would glide fairly well and yet still seal decently.

 

[elvisjer]

If i cannot easily find some type of bearing, felt will work for sure thanks!

 

[elvisjer]

Alright well i started the build and it's not working as well as I was hoping. I couldn't find a suitable rubber membrane so instead i just ported the box and then stretched fabric tight across it, and then am planning on attaching the drywall section to that. For the "ridiculous" testing section which we want to do, we need the platform to shake/vibrate violently. What would be the best way to do this? Is there any way we could modify the woofer to attatch a pole from the woofer to the platform without it self-destructing? Should I port the back box into the front box as well?

 

[JSlabotsky]

Reminds me of an episode of Mythbusters. They rigged a "woofer" that was basically a huge diaphragm moved by an electric motor and a connecting rod. Think single-cylinder piston engine type arrangement. It might be tough to get the frequencies you're after that way, though.

Or, why not suspend the platform "floating" directly above the driver. Leave just enough gap around it that it will move freely while still letting as little air pass by as possible. If you left little to no airspace between the driver and platform, I would think it would vibrate like crazy given enough power.

 

[elvisjer]

Alright sounds great. Im not wanting to ruin the woofer but i'm thinking i could somehow drill a hole in the dustcone and run a bolt through it with washers...if it was real clean and tight it should hold....right?