Fiberglass alternative with better performance than Poly-fil?

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g3rain1

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I know Danny prefers fiberglass, but I just don't like the idea of having that stuff around except maybe in a totally sealed design. Is there any substance that I can use as fill for my speakers that will perform better than poly-fil and isn't irritating like fiberglass. I was thinking of rockwool but I don't know if it's acoustic properties are any good.

Thanks.

richidoo

My .02:
I disagree that batt FG is a health risk. FG and Rockwool are similar material, similar health risk. Both have glue mixed in to hold it together. It only makes dust when being torn apart. Gentle breeze of reflex port isn't strong enough.

Alternatives for internal acoustic damping include Bonded Logic shredded denim insulation, I think it's more powerful absorber than FG.

Pillow fill polyester wool can be bought at any sewing store. My speaker kit (not GR) had this specified in the build instructions.

Acousta-Stuff is a specially processed polyester fill that has more damping than plain poly fill. The two batches I bought over the years looked different from each other.

Sheeps wool has been used and the advocates are very enthusiastic. It is less powerful than FG but it has that certified organic, "natural," magical, Welsh lore aspect that makes the golden eared DIYers cream.

GR Research sells No-Rez sheets which are very well received here on AC.

Since these all have different absorption coefficients, the amount and placement inside the box of each different material needs to be
experimented and tuned to serve the woofer's damping requirements. So when Danny says use 1/2 pound of FG batt, it's because that's the amount of FG that will do the job. If you decide to use wool or denim, then you would have to experiment with different amounts to learn how much is correct.

The amount and type of stuffing will affect the woofer response, so you have to decide on the stuffing before you advance to crossover design. And if you want to change a stuffing material then you should reevaluate the xo design. At least measure to make sure it makes the same response. Increasing the damping can reduce the SPL and overdamping reduces transient response.

After many DIY builds trying some of the above materials I use FG batt or 1" rigid FG panel now.

Shives

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That’s a great question. I spent sometime a few weeks ago looking. Sadly I found nothing that came up with better results. Lucky I was adding it to the sealed portion of this center channel, but the rest was Polly. Children around working speakers and flying glass to breath in I guess was a huge concern.

I understand there concern, to which is why I used poly. Not the shit that came with the speaker. I got a new bag of denser fill. Looking for something with more weight..

Best I came up with. But, hoping someone will add in some good news!

EkW

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“ Sheeps wool has been used and the advocates are very enthusiastic. It is less powerful than FG but it has that certified organic, "natural," magical, Welsh lore aspect that makes…”
Hempwool would satisfy both the organic and the vegan crowd. Right now it is hard to find or one must buy it by the pallet. From what I have read installers who have tried it prefer it over fiberglass batts.

g3rain1

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GR Research sells No-Rez sheets which are very well received here on AC.
I've already lined my cabinet with no-rez as per the build instructions, but also per the instructional video Danny made I need to fill the area behind the woofer with something.

Oh, I guess I neglected to mention in my opening post the speakers in question are XLS Encores and I was following the assembly videos linked on the product page. 

Since these all have different absorption coefficients, the amount and placement inside the box of each different material needs to be
experimented and tuned to serve the woofer's damping requirements. So when Danny says use 1/2 pound of FG batt, it's because that's the amount of FG that will do the job. If you decide to use wool or denim, then you would have to experiment with different amounts to learn how much is correct.

The amount and type of stuffing will affect the woofer response, so you have to decide on the stuffing before you advance to crossover design. And if you want to change a stuffing material then you should reevaluate the xo design. At least measure to make sure it makes the same response. Increasing the damping can reduce the SPL and overdamping reduces transient response.
Yeah, this was the concern that prompted my question in the first place. I don't have measurement equipment nor the time to experiment with dozens of different configurations of material/amount/position, and was hoping there was a known or generally accepted alternative.

x5472

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Does anyone have experience with the recycled jeans insulation (cotton)? Would it be dense enough to work?

mlundy57

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I use Acousta-Stuff

mikeeastman

I use the recycle cotton in both speakers and my acoustic panels and it worked very well and a lot less nasty to work with. It suppose have a high sound damping factor than fiberglass.

S Clark

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  • a riot is the language of the unheard- Dr. King
If you are worried about fiberglass, give a good dose of hairspray just before you stuff it in. 

WGH

I have used Kaypock with excellent results.



Kapok is an all natural fiber and is free of harmful chemicals. It’s grown in the rainforest without the use of pesticides, so it's completely all natural. When it’s harvested from the Kapok tree, the seed pods are manually picked clean and spun. After it’s spun, the silky fibers are ready to be used in pillows and meditation cushions.

Because Kapok is non-toxic, many people with chemical sensitivities find that it’s a good natural fiber choice, giving them another option to organic cotton.



Available at fabric stores and Amazon
https://www.amazon.com/Organic-Kapok-Fiber-Natural-Pound/dp/B014MY3YFM/ref=sr_1_2?dchild=1&keywords=kapok+fiber&qid=1623184589&sr=8-2

rpf

My .02:
I disagree that batt FG is a health risk. FG and Rockwool are similar material, similar health risk. Both have glue mixed in to hold it together. It only makes dust when being torn apart. Gentle breeze of reflex port isn't strong enough.

Actually the fibers of Rockwool are larger than those of Fiberglass and cannot reach deep into the lungs as the latter can. It is also less irritating to the skin. From experience, in use as wall and ceiling insulation, I've found (and read) that RW is better at sound deadening than FG. I also read a post (don't remember where) that stated it works better in acoustical panels but with that I have no experience.


walkern

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I've been using 'long fiber wool' stuffing for decades.  It works better than poly-fil and is a completely 'natural' product that doesn't shift easily when placed.  It's non-toxic (unless you are allergic to wool), and the fibers are WAY too large to migrate into one's lungs.  It's easy to fluff up to loosely fill gaps, and can be packed fairly tightly when that is what a speaker design calls for.

I've been buying it from Madisound since I first began DIY speaker building.  I've tried rock wool and dacron poly-fil just to hear the differences, and I've always gone back to long fiber wool.  I've never tried fiberglass as all my previous experience with it was as attic insulation where I found it VERY irritating to work with (both in my lungs in spite of using a mask, and on my skin).

Here is a link to access it at Madisound: https://www.madisoundspeakerstore.com/acoustic-damping/dampers-wool-stuffing/lb/

richidoo

Does anyone have experience with the recycled jeans insulation (cotton)? Would it be dense enough to work?

Imo it's the most powerful absorber material available because of the high density and porosity.

I have used 1" thick and 4" thick inside speakers. It provided too much damping and sounded too dead.
I like the stuff tho, so I got some 1/2" thick sheets to try in the future.