or Connect
AVS › AVS Forum › Audio › DIY Speakers and Subs › What's Best for Lining Internal Subwoofer Walls?
New Posts  All Forums:Forum Nav:

What's Best for Lining Internal Subwoofer Walls?

post #1 of 44
Thread Starter 
What makes the most sense for lining the inside walls of a subwoofer?

Regular fiberglass insulation or one of the following:

Rigid fiberglass panels, Rockwool, or sheets of thicker poly fill? How thick should those last 3 be if that's what gets used?

Thanks
post #2 of 44
Soft fiberglass. R13.

Definitely not the rigid OC703 type fiberglass. Rockwool would work as would polyfill. R13 is cheap and easy to attach to line walls of subwoofers.
post #3 of 44
Thread Starter 
If the rockwool or polyfill was used instead of the R13, how thick should it be?

I've seen a few different densities for the rigid fiberglass. Just curious why that wouldn't be a good thing to use. I've also seen the insulation in denser rolls about 1.5" thick. Would that be okay?
post #4 of 44
post #5 of 44
The cotton insulation is most friendly and equal in performance, and simple to work with
post #6 of 44
Quote:
Originally Posted by Erich H View Post

What makes the most sense for lining the inside walls of a subwoofer?
Type 700 fiberglass is the best material, but it's not readily available. One source is vinyl faced drop-in ceiling tiles, just peel off the facing. Fiberglas building insulation is one of the worst materials, as it can send fibers into the driver motor structure. Polyester, open cell foam, cotton and wool also work well. How thick to make it depends on the cab design. If vented an inch or two is adequate, if sealed it may need to be fully filled, possibly even compressed, which removes type 700 and foam from consideration.
post #7 of 44
bfm, have you seen the numbers on some of the recycled cotton? i was kind of surprised, but it seems to outperform fiberglass.
post #8 of 44
Quote:
Originally Posted by LTD02 View Post

bfm, have you seen the numbers on some of the recycled cotton? i was kind of surprised, but it seems to outperform fiberglass.
I haven't tried cotton, so I can't speak from experience. One reason why rigid glass works so well is the rigidity of the fibers, it's not just the resistivity coefficient.
post #9 of 44
Quote:
Originally Posted by Erich H View Post

Just curious why that wouldn't be a good thing to use.

Because rigid fiberglass doesn't do anything for bass. It's useful through the mid band. You want soft and low density for bass.

Quote:
Originally Posted by Bill Fitzmaurice View Post

Fiberglas building insulation is one of the worst materials, as it can send fibers into the driver motor structure.

Lol. No, not as long as you skip the part where you tear the stuff to shreds before you install it. tongue.gif
post #10 of 44
Lining the walls of a sub with anything is pointless with any reasonably normally dimensioned sub. Attenuation at typical sub frequencies from these materials is marginal at best.
post #11 of 44

IMO, it depends.  You talkin ported or sealed. 

 

I have used OC 700 series, Polyfill, and pink fluffy.  Sealed I like fiberglass whatever variety you like the performance of, I like OC700 series glued into the walls.  IMO for a ported I like the polyfill, rockwool, or jeans material just b/c I'm a little paranoid on fiberglass being shot out the port like a fiberglass cannon.  Those fibers are in there vibrating, presumably some are breaking too as they do thier purpose and those particles go somewhere right?  If you can keep the polyfill from obstructing the port it can work well medium-loosely packed also. 

 

I haven't used Linacoustic(in a sub) but it seems to be a likely good performer also with approx the same performance as OC700 series.  Its also easier to use than fiberglass, less itchy and coated on one side.

 

I can tell you I prefer the sound of a ported sub with the interior treated from my own testing.  Standing waves are not the only enemy of SQ present inside a ported enclosure that need attenuation.

 

When stuffing sealed I am typically am adjusting the apparent Q.

post #12 of 44
Quote:
Originally Posted by Scott Simonian View Post

Because rigid fiberglass doesn't do anything for bass.
Rigid glass works just as well in the bass as any material, and it's better than most. It's only limitation is that it shouldn't be compressed, so it won't work as well as cotton, wool or polyester as a stuffing material in a high Q sealed cab or in a transmission line.
Quote:
Lining the walls of a sub with anything is pointless with any reasonably normally dimensioned sub. Attenuation at typical sub frequencies from these materials is marginal at best.
The point of lining a sub isn't attenuation of sub frequencies, it's attenuating the harmonics of the sub frequencies created by the driver, reducing THD.
post #13 of 44
Anymore I don't line with vented or sealed cabs I just put a poly pillow or two in there. The point of it is not to do anything to the low bass but to knock down resonances and harmonics due to cabinet dimensions, port length, etc...Nasty stuff above 150Hz usually but that can be audible when excited if you ever wanted to crossover higher or use a shallower slope.
post #14 of 44
Thread Starter 
The denim insulation seems to do pretty good. Would 3.5" thick be the recommendation, or would the 1.5" thick rolls be good enough?
post #15 of 44
I just cram pillows in there. I stopped lining any of my sub walls quite a while ago.
post #16 of 44
I don't feel too bad about reviving this thread as it's only a couple weeks old and I'm entering my first build, lol.

This fill business fascinates me a bit, I must say.

First, it seems we pay close attention to the internal volume of a cabinet, only to "stuff" with a bunch of fill, lol. Most of the cab calcs I've seen account for everything in the cabinet, including the battens/bracing and driver...it doesn't appear there's anything accounting for "fill" that I have bore witness to. (?)

What makes IT so special? tongue.gif

Second, I've seen that the Walmart poly fill pillow seem to be a popular choice. Correct? And if so, any particular density/brand, etc? Do subs like it soft, medium, or firm? smile.gif

Finally are these literally STUFFED in the cab, or adhered/stapled to the cab walls?

It just seems a bit odd to me that so much attention to the details of the cab seem to be paid, only to be finished off with a seemingly unending array of materials and volumes of "stuffing".

Does it really not affect the internal volume substantially and therefore, the performance of your subwoofer?

Thanks all, just trying to do this as right as possible the first time.

James
post #17 of 44
Quote:
Originally Posted by mastermaybe View Post

I don't feel too bad about reviving this thread as it's only a couple weeks old and I'm entering my first build, lol.
This fill business fascinates me a bit, I must say.
First, it seems we pay close attention to the internal volume of a cabinet, only to "stuff" with a bunch of fill, lol. Most of the cab calcs I've seen account for everything in the cabinet, including the battens/bracing and driver...it doesn't appear there's anything accounting for "fill" that I have bore witness to. (?)
What makes IT so special? tongue.gif
Second, I've seen that the Walmart poly fill pillow seem to be a popular choice. Correct? And if so, any particular density/brand, etc? Do subs like it soft, medium, or firm? smile.gif
Finally are these literally STUFFED in the cab, or adhered/stapled to the cab walls?
It just seems a bit odd to me that so much attention to the details of the cab seem to be paid, only to be finished off with a seemingly unending array of materials and volumes of "stuffing".
Does it really not affect the internal volume substantially and therefore, the performance of your subwoofer?
Thanks all, just trying to do this as right as possible the first time.
James
Your questions have already been asked and answered here, a number of times. Do a search.
post #18 of 44
^ Oh. Well, how do you suppose I found THIS thread? By conducting a SEARCH of course. And seeing it's three weeks old, I suppose at least one other likely found the same incomplete and contradicting info that I discovered on a similar "fill" subject.

there's two questions...

I read this thread and nary did I find an explanation as to why the "stuffing' seems to not matter in regards to the internal cab volume.

I did not find anyone speaking as to a particular density/brand of pillow/fill that's optimal. If that's a viable solution, I'd like to go that route: it's readily available, contained, and inexpensive.

But if HERE means AVS as a whole, as I assume, I have also done that as well of course...ditto for google, and have found nothing but nothing...and incomplete and contradicting information.

Thus, the reason for asking here.

Now, if someone can explain why "fill" doesn't adversely/significantly affect cabinet volume (or if it does, why do so many seem to add it so casually to otherwise carefully calculated degins) I'd appreciate it. Else, please forgive my poor search skills and point me in the right direction.

thanks,

James
Edited by mastermaybe - 10/11/12 at 8:57am
post #19 of 44
forget the "making the driver see a bigger cabinet thing" Remember where it said in this thread that stuffing the cab assists interior cabinet resonances. Why do you treat the walls in your theater with sound-deadening? same exact concept, just a larger box, AND YOUR INSIDE IT!!!!
post #20 of 44
^ Is this directed at me? If so, that's not my consideration and certainly not something I proposed.

"Remember where it said in this thread that stuffing the cab assists interior cabinet resonances."

Assists? You mean dampen/reduce?

I understand why you treat walls in an acoustic environment. But that doesn't help me with my question of: does filling a subwoofer cabinet adversely/significantly affect internal volume.

thanks

James
post #21 of 44
Quote:
Originally Posted by mastermaybe View Post

But that doesn't help me with my question of: does filling a subwoofer cabinet adversely/significantly affect internal volume.
No.
post #22 of 44
Quote:
Originally Posted by Bill Fitzmaurice View Post

No.

thanks sir, that was my assumption.

I appreciate it.

James
post #23 of 44
Quote:
What makes IT so special?

I was answering this simple question, and, as BFM stated already, my response is the main reason people use poly, much more so than the box volume deal.
post #24 of 44
Quote:
Originally Posted by beastaudio View Post

I was answering this simple question, and, as BFM stated already, my response is the main reason people use poly, much more so than the box volume deal.

Unfortunately, you answered a question I didn't ask. I understand why the poly fill is used. The question was, again: why it's (the poly fill) not computed/accounted for when calculating the internal volume of the cabinet as it seems, all else inside the cab is (why would it be "special" in that regard). I wasn't referring to its use/intrinsic value and I thought the context of which the question was included within made that clear, I'm sorry that it apparently was not.

My guess is that its mass is not significant enough to provide a meaningful difference, whereas bracing and the driver basket/motor structure IS. Bill simply adding "no" affirms my assumption unless there's something else going on.

thanks

James
post #25 of 44
That is pretty much the case, consider the fact that the materials volume if completely compressed would take up so little of the box, that it would be even less significant than the driver's displacement. bottom line is, on sealed boxes, even a .5cuft isnt going to skew change much of the response of the system enough to be concerned in the subwoofer realm. I understand your concern though, as it seems even you wanted to be "exact," that you would have to take this into account. Perhaps the act of using the poly and it making the driver see a "slightly bigger box" makes up for the airspace it takes up, there for leaving the overall effect (on box volume) a break-even
post #26 of 44
thank man. Yeah, I think I'm being much too anal about this entire operation, so far. Seems to me that if I construct a solid 3.5-4.5 box I'm going to be in good shape and will simply adjust my power input accordingly.

So are people actually tossing full blown pillows in their subs or removing the fill?! Can it just rest in there or do I need to adhere it to the cab walls?

thanks again.

James
post #27 of 44
Quote:
Originally Posted by mastermaybe View Post

I did not find anyone speaking as to a particular density/brand of pillow/fill that's optimal. If that's a viable solution, I'd like to go that route: it's readily available, contained, and inexpensive.

Everybody just gets the cheap $2.50 walmart pillows. If you want to get fancy you can get those sleep number pillows, my smaller subs like a sleep number of 75 but my big subs are more partial to 50 tongue.gifwink.gif
post #28 of 44
Quote:
Originally Posted by mastermaybe View Post

thank man. Yeah, I think I'm being much too anal about this entire operation, so far. Seems to me that if I construct a solid 3.5-4.5 box I'm going to be in good shape and will simply adjust my power input accordingly.
So are people actually tossing full blown pillows in their subs or removing the fill?! Can it just rest in there or do I need to adhere it to the cab walls?
thanks again.
James

I have seen both. I think Jeff lines his subs attached to the Cabinets. There are pics in the Cap thread that shows it but I am not sure what fill he uses.
post #29 of 44
Quote:
Originally Posted by mastermaybe View Post

thank man. Yeah, I think I'm being much too anal about this entire operation, so far. Seems to me that if I construct a solid 3.5-4.5 box I'm going to be in good shape and will simply adjust my power input accordingly.
So are people actually tossing full blown pillows in their subs or removing the fill?! Can it just rest in there or do I need to adhere it to the cab walls?
thanks again.
James

For your size box about 2 to 3 pillows will be fine with the covers attached.
post #30 of 44
Maybe one on either sidewall and the top/bottom?

Staple em', no? Prolly better off with adhesive?

Or just the "smoosh" method? smile.gif

thanks.

James
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: DIY Speakers and Subs
AVS › AVS Forum › Audio › DIY Speakers and Subs › What's Best for Lining Internal Subwoofer Walls?