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Thread: Rockwool, yes or no

  1. #1
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    Rockwool, yes or no

    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?

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    Senior Member RMC's Avatar
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    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


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    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.

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    Senior Member RMC's Avatar
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    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


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    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

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    Quote Originally Posted by DualTriode View Post
    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.

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    Senior Member RMC's Avatar
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    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

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    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by RMC View Post
    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

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

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    Senior Member DES-1's Avatar
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    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.

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    Quote Originally Posted by DES-1 View Post
    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


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

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    Senior Member RMC's Avatar
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    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


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    Senior Member DES-1's Avatar
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    Quote Originally Posted by Earl K View Post
    Maybe this was the info you were referring to?

    Widgets Post

    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/inde...egory_id/45003

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    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.

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