I am doing a removable bottom on my sealed 3-way monitors that will house the x-over components. As such I can not brace it since the crossover is in the way and I figure that the next best thing to bracing is dampening. I plan to put a layer of bitumen down on the bottom first, then mount th crossover to it, or maybe it would be better if the bitumen were attached to the outside of the cabinet to the bottom of the bottom out of sight.
Either way, I am looking for a us source of an appropriate bitumen pad or suitable material....and thoughts?
Thx
Either way, I am looking for a us source of an appropriate bitumen pad or suitable material....and thoughts?
Thx
Alternative
Mount the crossover in a separate box that has a cover oversized so that it closes off the opening in the loudspeaker enclosure when fastened there.
Regards,
WHG
P.S.: For various acoustic materials, visit McMaster-Carr's website: http://www.mcmaster.com/
Mount the crossover in a separate box that has a cover oversized so that it closes off the opening in the loudspeaker enclosure when fastened there.
Regards,
WHG
P.S.: For various acoustic materials, visit McMaster-Carr's website: http://www.mcmaster.com/
Last edited:
Is Dynamatt a similar material...I see that is is made from butyl rubber but I think it does the same thing?
Isn't "bitumen sheet" just what we call "tar paper" over here?
For something probably better I'd look at SheetBlok . . .
No, tar paper refers to either a paper or a felt saturated with asphalt or coal tar pitch.
Bitumen sheet usually refers to a peel and stick type membrane, much thicker than tar paper. It's self adhesive and has a facer. It's used for waterproofing, eaves protection and underlay for low slope roofing. If that's what you want then go to your local building supply store. Personally though, I would consider using a peel and stick lino floor tile before bitumen sheet. Not so stinky and may actually do a better job.
Asphalt Impregnated Felt …
… for Low-Pitch Roof Decking is the “Bitumen Sheet” of interest here.
In its modern form, it is a relatively thick, asphalt impregnated felt used to construct built-up roof membranes. See [1] for an example of this. Coal-Tar is no longer used as an impregnate due to installer health issues.
[1]
… for Low-Pitch Roof Decking is the “Bitumen Sheet” of interest here.
In its modern form, it is a relatively thick, asphalt impregnated felt used to construct built-up roof membranes. See [1] for an example of this. Coal-Tar is no longer used as an impregnate due to installer health issues.
[1]
Bitumin is, as far as I know, British for "tar". The stuff I have seen had a regular pattern of holes in it (to not trap air) and a peel and stick face. Frequently it is used to quiet a sheet metal chassis for electronics gear. It is good for thin metal but becomes less good for thicker wood. Multiple layers help.
I would always recommend that the stick on sheets be given a few staples around the perimeter, otherwise they tend to fall off over time.
Adding ceramic tiles, especially if a lossy glue layer is used, is also highly recommended.
David
I would always recommend that the stick on sheets be given a few staples around the perimeter, otherwise they tend to fall off over time.
Adding ceramic tiles, especially if a lossy glue layer is used, is also highly recommended.
David
I wonder if the psa butyl rubber flashing sold at home improvement stores would work? I am just trying to dampen a removable bottom since it will have the crossover on it, I can't brace it. It is 6.5" x 10" at is largest dimension (curved sides)... Maybe I should not mess with it at all?
Is that the really heavy rubber stuff? It would probably be good. At Snell we used a dual layer baffle with fairly thin butyl rubber between the wood layers and it worked well. (K.5, E.5, XA75, XA90)
David
I wouldnt call it really heavy at 35 mills but the "foilastic" is what I am specifically referring to:
http://tapes.berryplastics.com/Data...o/FlashingTapeManual/Section2_ProductData.pdf
http://tapes.berryplastics.com/Data...o/FlashingTapeManual/Section2_ProductData.pdf
As I keep pressing, the key is a good ratio of damping material to rigid wall layer. Heavier rubber and possibly thinner wooden panels are required to knock down panel Q. So if your cabinet walls are pretty substantial then a thin layer of fairly light damping may have a minor effect.
In cases like that you should consider contrained layer damping. That is a three part sandwich with rigid outer layers and a high loss center layer. This is a more efficient approach, which can work with very thin damping layers.
David S.
In cases like that you should consider contrained layer damping. That is a three part sandwich with rigid outer layers and a high loss center layer. This is a more efficient approach, which can work with very thin damping layers.
David S.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.