Rockwool, yes or no

[Drugolf]

Trying to determine the route to go for insulation in various Altec builds. I thought i had it determined that the Owens Conrning 703 unfaced 1" thick boards would be best, and they may, but I can't get it here. They require huge quantities. it appears to be available on Amazon, but shipping is not Prime and really expensive.

I can get the Roxul Rockwool AFB product 2" thick for $52.91 /bag. About $.55/sf

Rockwool still a viable option?

[RMC]

Hi Drugolf,

JBL does not recommend the use of Rockwool, but they don't say why... I assume its not enough soft, fluffy and absorptive.

See attached picture from page 6 of the JBL E series Instruction Manual. Regards,

Richard


83781

[sguttag]

I wonder if they are concerned about it being airborn or not. I have Rockwool in the ceiling joists as a barrier to the floor above and plan to have rockwool in the walls as an acoustic barrier (working on the room now). However, on the wall face itself, it will be less aggressive and more traditional fiberglass and/or duct liner.

[RMC]

Hi Drugolf and Sguttag,

Another place where JBL mentions the same not recommended for Rock wool, but this time "not" is in bold and underlined in the original document...

So they are pretty consistent! This one being JBL Enclosure Construction Manual, Page 6. Regards,

Richard


83782

[DualTriode]

Hello,

Read the cancer warning on the bag.

Think about the fibers being pumped out of the reflex port for you and your children to breath.

Thanks DT

[gasfan]

Hello,

Read the cancer warning on the bag.

Think about the fibers being pumped out of the reflex port for you and your children to breath.

Thanks DT I don't believe those extruded fibers used for insulation are carcinogenic, however rock wool is far more irritating than glass wool. Also far more prone to being suspended in air. You can bet you'll have a steady supply flying out the ports of your speakers. Get that in your lungs and you'll be hacking for a week. I know since I'm in construction and around it often. I have to wear a respirator when rock wool is being installed, it's just everywhere. Contrary to what you may read about it, the fibers are way finer than glass wool, hence the heightened irritability. Mind you there is a variety of both on the market but this has been my experience. I would stay away from either and choose a stable alternative, ie: open cell whatever.

[RMC]

Hi DualTriode & gasfan,

Thanks for the input on Rockwool. Two interesting point of view.

As for me, I know Rockwool from seeing it all the time front row insulation at the local Home Depot store, but never used it in the house nor in my DIY boxes.

In the past I always used insulation type fiberglass in speakers. However, sometime ago I started purchasing polyester instead.

Insulation type fiberglass seems to have too many fibers flying in the air when manipulated or vent passing a good amount of air, unless its wrapped loosely in one layer of cheesecloth before tacking it in place or sprayed a little with some spray paint. Polyester doesn't appear to have that fiber issue.

So I'm slowly replacing the fiberglass in all my DIY boxes with 1-1½" polyester sold by Solen as well as others. Regards,

Richard

[Mr. Widget]

In the past I always used insulation type fiberglass in speakers. However, sometime ago I started purchasing polyester instead.

Insulation type fiberglass seems to have too many fibers flying in the air when manipulated or vent passing a good amount of air, unless its wrapped loosely in one layer of cheesecloth before tacking it in place or sprayed a little with some spray paint. Polyester doesn't appear to have that fiber issue.

So I'm slowly replacing the fiberglass in all my DIY boxes with 1-1½" polyester sold by Solen as well as others.In my experience polyester does not work nearly as well as fiberglass or the blue denim cotton batting you can get as house insulation. When I use fiberglass I use 1” non-shedding insulation. Standard wall insulation is horrible to work with.


Widget

[Drugolf]

Widget, can you elaborate on 1" non-shedding insulation? What is that and where do you find it?

[DES-1]

Wrap-on 1" in large rolls may be what he is referring to. I used last year and included a link to a past thread and the supplier website but no longer see the post.

[Earl K]

Wrap-on 1" in large rolls may be what he is referring to. I used last year and included a link to a past thread and the supplier website but no longer see the post.

Maybe this was the info you were referring to?

Widgets Post (http://www.audioheritage.org/vbulletin/showthread.php?3825-Damping-Material-(Fibergalss)&p=35394&viewfull=1#post35394)

:)

[Drugolf]

Doesn't look like they have it any more.....based on nothing on their web site.

[RMC]

Hi Widget,

Thanks for the reply to my post.

Below is your Dec. 1, 2004 post that Earl referred to:

"I use Wrap-on fiberglass insulation. It is virtually identical to the stuff used in the classic JBLs. It is 1" non shedding, and yes it is yellow. You can get a 24" wide by 50' roll in a box (part number 16550) shipped to you for around $30. Contact http://www.wrap-on.com/ and they will give you the name of a near by stocking distributor or as in my case a distributor willing to ship it to you.

I have used this stuff for years and it is by far my favorite. Unlike house insulation it doesn't sag with time and since it is non shedding it is much nicer to work with. If you need two inch, you can double it up.

Egg crate foam is my next favorite choice but it is quite costly.

Widget"

I did try the wrap-on web site mentioned above however it looks like the company may have changed or now puts emphasis on other products? On the pictures attached you can see the products they mention have nothing to do with 1" fiberglass, though I have not downloaded their whole catalog since they require info just for doing that. Drugolf appears to report the same as me.

RE: "In my experience polyester does not work nearly as well as fiberglass"

I may tend to agree with you on the basis fiberglass does seem to have more density than the polyester I found and also I've seen some lower absorption coefficients than fiberglass. Maybe this could explain your results with polyester?

Since the role of fiberglass or other is mainly to absorb midrange reflections inside a cab, to minimize colouring the sound, then I assume for bass cabs only (< 300 hz or so) the product used may not make much audible difference.

I use mostly (not exclusively) bass cabs bi-amp with satellite speakers, allowing me the flexibility to make various bottom/low mid-high combinations, and still have some egg crate foam pieces left for use in some other smaller boxes.

RE: "fiberglass I use 1” non-shedding insulation. Standard wall insulation is horrible to work with."

Unfortunately I have not seen this product in stores locally, would need to dig more with specialized insulation companies I guess. But I do agree working with standard insulation is horrible: its fiber hell inside a cab when not restrained by cheesecloth or a little spray paint.

Checked again the local Home Depot online and seen no such product available there. It could be made available only to building material or insulation distributors, and only in the US? Local Lowes owned stores didn't provide anymore success.

However, I did see locally the recycled denim cotton based insulation, being 2" thick and cotton, but the latter is on JBL's list of "NOT" recommended shown on posts # 2 & 4. Maybe because of cotton dust it produces?

So for now here in Canada it looks like its either hell with building insulation, or going for polyester as a lesser of two evils... Regards,

Richard


8378783786

[DES-1]

Maybe this was the info you were referring to?

Widgets Post (http://www.audioheritage.org/vbulletin/showthread.php?3825-Damping-Material-(Fibergalss)&p=35394&viewfull=1#post35394)

:)

That's the one! I had linked to your post in a thread and used your provided link from that post and was surprised it was working in early 2018. The Wrap-on worked very well with the 3M spray adhesive. Still have about a third of a roll to donate to anyone willing to pick up just north of Columbus, OH.

Amazon shows it as no longer available, but I bet there are some rolls still out there available. This place may still have it in stock but then again maybe they haven't updated their inventory: https://hardwareonlinestore.com/index.php/component/virtuemart/view/productdetails/virtuemart_product_id/41923/virtuemart_category_id/45003

[Drugolf]

I've made a lot of calls the last two days to various insulation suppliers etc and it seems that like most things, nobody will stock the odd items like the Owens 703. It is still made, but here at least you would need to order a half truck of it only. It is available on Amazon it appears, but at significant cost.

I tell you what, between trying to find suitable cotton insulation for Bozak applications (no longer exists) and this, finding suitable insulation products other than poly is getting to be very difficult to say the least if darn right near impossible. I have even had the same issue with foam or batting for re-upholstering furniture pieces as all that seems to be available there too is high density foams which frankly kinda suck.

At this point, If I can find simple 2" thick unfaced fiberglass insulation at a reasonable price, I'll be happy. They do sell the small rolls of it at the home improvement stores for use in tight spots needing some insulation for about $5.50 for 48". Would need several for most speaker cabs at least. Ugh. As far as spraying it to keep some of the glass fibers from getting lose, yes, you could use any fixative type spray including hairsray. Fixative is used in art to keep pencil and charcoal drawings from getting smudged. I would think it would be a little lighter than a paint.

[RMC]

Not sure if fixative hairspray would last as long or forever as spray paint though.

Richard

[rusty jefferson]

I use wool for speaker projects. You can purchase it in "ropes" or roving, which are simply loose hair that has been wound but not woven into a long slender shape resembling a rope. They are very easily pulled apart to create quite the pile of fill. You want low bulk wool, not high. I purchase mine here:
http://www.customwoolenmills.com/wool_shop/carded_wool/wool_insulation_rovings
They can advise based on what they have available. They ship to the States. The 5-7 pound bag would fill a normal-ish sized speaker cabinet. I think I've been using about a pound per cubic foot.

Quite a bit more expensive than fiberglass, but a pleasure to use and highly effective, imo.

[sguttag]

Oh...one more downside to Rockwool in a speaker...you can only work with it once. Once you get to the second handling, it will start falling apart (which in a speaker would mean it would blow out of the ports).

[rusty jefferson]

I use wool for speaker projects.....
I probably should have said I use wool, as in from sheep, not Rockwool.:)

[Mr. Widget]

Madisound sells carded wool... very old school and very good. Not cheap though.


Widget

[dubkarma]

I used that dense 703 compressed fibreglass in a pair of Augspurger monitors—contrary to what George Augspurger recommended. My (naive) thought was that the more completely the damping material absorbed the back-wave from the TAD drivers (which are crossed over at 800 Hz), the better.

My mistake. The 703 fibreglass sucks up too much of the sound and deadens the sound of the speakers. With two inches of much lighter Dacron, the speakers sound more dynamic and lively.

Just my experience.

[RMC]

Hi dubkarma,

If you look at JBL's Enclosure Guide, second page, Insulation section, they mention "If you must use dacron or felt instead of fiberglass, subtract its volume from the box (make the box bigger)."

So Dacron, specially 2" thick, must reduce the effective box volume quite a bit, which may explain your "sound more dynamic and lively". Maybe LF bump (amplitude) caused by the smaller box than it seems?

Regards,

Richard

[Drugolf]

I finally found some of the OC 703 fiberglass. Tracked some down through a local insulation contractor instead of a direct supplier. He had to order it for me, but he does on occasion anyway. Knew exactly why since they have helped a couple local venues with their acoustical panels for live music etc.

dubkarma, how much of the 703 did you use? This is probably why many of the designs call for only 3 walls to be lined.

[JoeNelis]

My advice is to use Mundorf Angel hair. I used this I my JBL DD55000 Everest project I’ve just finished and it’s fantastic.

[Kay Pirinha]

I'd prefer mermaid hair, felted in clear full moon nights, over this ;)!

Best regards!

[dubkarma]

I finally found some of the OC 703 fiberglass. Tracked some down through a local insulation contractor instead of a direct supplier. He had to order it for me, but he does on occasion anyway. Knew exactly why since they have helped a couple local venues with their acoustical panels for live music etc.

dubkarma, how much of the 703 did you use? This is probably why many of the designs call for only 3 walls to be lined.

I believe it was 2" thick panels. (Augspurger had recommended 2" of the regular pink fibreglass, but on all interior surfaces except the front baffle.)