polyfil

 

Guess it would depend on the application. I just make sealed boxes so I don't stick anything in them. I make them with bassbox pro with the specs for the sub and call it good.

 

Do you mean spraying the insides with something? On my old sealed box I sprayed the inside with Plasti-Dip spray (which is a liquid rubber) and put a piece of eggcrate foam on the back wall opposite the subwoofer.

 

Nada.

 

nuttin

 

zero.

 

Nothing at all

 

I was just working on a friends truck and he has a Dayton 10" HF. We lined the box with acoustic foam from parts express. What was good about this is we could put more and more in the box until the bass sounded tight. It was a combination of the foam and making the sealed box the right size because it was to big to begin with, but it definately helped alot. When I get the chance I want to build a box to the equivalent size of what it is now with the foam but without the foam and do some response measurements etc and see what the foam itself exactly did. We got the sub to pretty much dissapear and the rattles went away. So try it out its not that expensive and it may work for you. Here's the link of the foam.http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=260-515. Hope this helps

 

I always thought putting polyfill in an enclosure was to trick the sub into thinking it was in a bigger box when you have it in a box that's smaller than the specs call for. What you're describing is the exact opposite of this.

The polyfil slows down the soundwaves and thus it acts like it's in a bigger box because it takes the soundwaves longer to bounce off the walls. Or at least that's how I understood it. But I could be wrong.

 

Nothing was really needed but i did layer of cascade quiet kote, ensolite, and eggshell on all surfaces, its dead solid, and dosent resonate even the slightest bit. Also FG box that is.

 

I just stapled 3/4" to 1" of polyfill to each internal wall....

Want to try the eggcrate foam idea, if we use it on our mids why not on subs eh?

 

 

LOL. Awesome...

 

I did a box for an IDQ12 with Dynamat spray that worked really well but for the most part now it's Dynaxorb pads and polyfill.

 

Eggcrate,poly,and Dynamat on the outside.

 

Poly +1

 

MDF boxes with nothing -except wooden bracing- on the inside sounds best to me.

I made some full glassfibre boxes before, I also used to make smaller boxes filled with wool, I used to put poly and/or bitumen on the inside of the box...
It never sounded completely 'right' to me. Tuning with wool helps, but it won't make it sound completely like I want it to...

I do use poly and bitumen to kill resonance and make the box airtight, but I only put it on the outside to maintain the natural sound of an MDF box.

The box I'm currently building:
- material: 30mm MDF
- glue: normal wood-glue where the pieces fit perfectly, PU-glue where the pieces fit, but not 200% perfect.
- screws: Only the amount thats absolutely necessary to keep the box together while the glue is drying. Pre-drilled the holes and used long screws so they can be tightened well.
- bracing: 30mm MDF
- airtightening and resonance killing: 3 layers of 300g/m² glassfibre + poly-resin on the outside of all panels except the baffle; 5 layers of 300g/m² + 1 or 2 thinner 'finishing' layers of glassfibre + poly-resin + 2 layers of bitumen on the baffle
- finishing: black jeans with a thin layer of mousse underneath

I think this should be dead enough for a 12" Peerless XXLS sub and 2 10" Peerless XLS PR's

greetz,
Isabelle

 

My last two projects I sprayed the inside of my mdf boxes with the sound proofing rubberized undercoating from Wal Mart. Does this help? I can't verifiably say!:blush: But when I tap on the box there is no hollow sound (resonance). It sounds solid! I also stuff with polyfill depending on needs.

 

here's a great example that i found and outlined.

-fixtion

 

That would be zaph's 2.5way Waveguide.

 

Subscribed for abmolech's response.

 

ED V4 and poly

 

I just sprayed the inside of my ported box with rubberized undercoating that can be found at any autoparts store. I'm not sure it did anything, but I'm sure it didn't hurt...

-Matt

 

I had a Infinity 1230w in a sealed box and tried with and without polyfill and they both sounded DIFFERENT but I couldnt tell which one sounded better haha.

I just left the polyfill in because my girlfriend said it sounded better.

 

I use a lacquer on the insides of the box.

 

I think some people put materials in a sub box that really cannot absorb or even slow down waves of those frequencies. I'd definitely try to mass load fiberglass boxes in some way.

 

lolcats <3