[mclsound]

I am going to start my new 4way and someone mentioned trying PL9000 construction adhesive on the cabiets....anyone tried this????
Also wondering your take on roxul...since i have a bag left over from my ht room.
thanks john

[Peter J]

Can't help you on the Roxul, but know plenty about glues. Assuming you're using MDF and it's fitted decently, I'd stick with TiteBond 1 for most everything. It's inexpensive, easy to use and stronger than the wood it'd gluing in most cases.

 If you're needing to fill big gaps in joints, my choice would be PL Premium, works but needs to be fairly warm to remain workable. Trust me, wear gloves or you'll be wearing it for some time.

 In my mind, there needs to be a good reason to use thicker glues and construction adhesives. It's not commonplace in cabinetmaking. Glue is no substitute for sound constuction.

[mclsound]

thanks peter

[Letitroll98]

And for the Roxul, I assume you are referring to the Rockboard product, which is manufactured at different compressive strengths and different thicknesses for different uses, don't know which one you have leftover from the HT.  Very similar to Owens Corning 705 in absorptive co-efficients, more even in frequency as you get to 3" thick and up, thinner starts to drop off precipitously below 250Hz.  Haven't used it myself in speakers, but I understand the recommendations are for 4" on the front and rear, 2" on the sides.  Easier to form and rout than OC 705.   

[mclsound]

I was talking about the insulation as i have a bag of 2x4 and 2x6.I am using a combination of 1 and 1.25" MDF along with 1" Baltic birch for all internal structuring ....for eg.
1.25"MDF-sides and outside bottom layer
1"MDF-front middle layer and some bracing
1"BB-back,all midbass structure,vent,inside front,top
The entire cabinet will be wrapped with a .5" layer of BB
49"Hx29"Dx12"W internal dimensions
Not small or light
I was thinking of using the PL9000 for internall glueing(just a thought?)
I also have some acoustical eggcrate foam and roxul for inside
I will front fire all vents and I am looking into Wywires for all mid/hi internal wiring.
Project starts this week.

[Cacophonix]

I've used roxul before for acoustic panels, and they work very well. I used it to damp my subwoofer as well.
Looks like you are trying to use CLD technique to build your cabinets. You might want to look into a glue that forms a flexible bond between your MDF and BB. If i recall correctly PL9000 cures hard. And on top of it, its very difficult to work with.

[Letitroll98]

Hey, good luck with the build, sounds ambitious.  Roxul is a brand name for about 25 different rock wool products.  The two major products used for audio applications are Rockboard and Safe'nSound.  Rockboard is a stiffer product that can be shaped and molded, and has higher sound absorption co-efficients below 250Hz than the same thickness of Safe'nSound, which is the floppy sound insulation product I now think you're referring to.  But yes, both products will work very well as interior insulation of speaker systems.  I'm not too fond of foam products for sound insulation, they can be okay for high frequencies, but are very uneven across the full audio spectrum.  If dense enough, foam can be used to good effect as tweeter surrounds, but not much else.  Let us know how the build progresses.