Hello All,
I did a search first - I've read about using rope caulk/Mortite to damp woofer frames, and one post talked about using strips of it to partially line a speaker enclosure, so...
I was wondering if anyone has ever used this stuff to completely line the inside of a speaker cabinet to damp resonances?
Would it work? Is it practical? Cost effective? Would you still need to address standing waves, etc. with stuffing?
I'm also wondering if there are other substances out there that might be used to do this - like the kind of clay that doesn't harden - what is that, some kind of artist's clay?
I guess anything with moisture in it would probably be a bad idea, but anything that remains soft and pliable without leaching moisture might be a possivility.
Well, just thinking out loud here, so please feel free to think out loud back!
I did a search first - I've read about using rope caulk/Mortite to damp woofer frames, and one post talked about using strips of it to partially line a speaker enclosure, so...
I was wondering if anyone has ever used this stuff to completely line the inside of a speaker cabinet to damp resonances?
Would it work? Is it practical? Cost effective? Would you still need to address standing waves, etc. with stuffing?
I'm also wondering if there are other substances out there that might be used to do this - like the kind of clay that doesn't harden - what is that, some kind of artist's clay?
I guess anything with moisture in it would probably be a bad idea, but anything that remains soft and pliable without leaching moisture might be a possivility.
Well, just thinking out loud here, so please feel free to think out loud back!
An interesting idea!
I'll admit I've been thinking about it, but have not tried it.
Rope caulk does work very well on the back of horns, metal or plastic, as well as woofer frames. I'm glad I found the stuff, used to use messy tar on the back of horns.
But would it work on the walls of cabinets? It would certainly add mass and dampen resonances, just as it does elsewhere. But wouldn't it reflect sound a bit?
Let's hope some folks who know more about it will chime in.
I'll admit I've been thinking about it, but have not tried it.
Rope caulk does work very well on the back of horns, metal or plastic, as well as woofer frames. I'm glad I found the stuff, used to use messy tar on the back of horns.
But would it work on the walls of cabinets? It would certainly add mass and dampen resonances, just as it does elsewhere. But wouldn't it reflect sound a bit?
Let's hope some folks who know more about it will chime in.
I think it will do the job but perhaps be less than cost effective. You'd need a huge amount of those packages of strips. Also, you will need a way to fasten it as it has poor adhesive qualities and will fall off the sides and top. It's great for seating a big driver though.
Do you have a supply of it?
Do you have a supply of it?
No Cal I don't have a supply - I'm wondering if it can be purchased in bulk perhaps.
And yes cost could be a big factor, so I'm wondering if there are alternatives - like clays etc.
I saw a photo somewhere once (it may have been on this site but I don't remember the source) where a guy had put huge amounts of something that looked like clay on his woofers - it looked pliable as it had molding marks all over it - he obviously applied it by hand and formed it as he went - like molding clay.
Maybe there are other putties out there like rope caulk that are cheaper and come in larger quantities. Back to Home Depot I go!
Also going to do a search on the web - might be able to find something at builders's supplies or hobby/arts/craft supplies. If I come up with anything I'll re-post.
And yes cost could be a big factor, so I'm wondering if there are alternatives - like clays etc.
I saw a photo somewhere once (it may have been on this site but I don't remember the source) where a guy had put huge amounts of something that looked like clay on his woofers - it looked pliable as it had molding marks all over it - he obviously applied it by hand and formed it as he went - like molding clay.
Maybe there are other putties out there like rope caulk that are cheaper and come in larger quantities. Back to Home Depot I go!
Also going to do a search on the web - might be able to find something at builders's supplies or hobby/arts/craft supplies. If I come up with anything I'll re-post.
P.S. -
As far as adhesion goes perhaps the cabinet could be built as a sandwich, with the caulk in between the layers, and ribs could be used to form a framework between the layers and provide further strengthening/damping.
Ooooooh! Lotsa work this would be, but it might make an awesomely dead cabinet.
As far as adhesion goes perhaps the cabinet could be built as a sandwich, with the caulk in between the layers, and ribs could be used to form a framework between the layers and provide further strengthening/damping.
Ooooooh! Lotsa work this would be, but it might make an awesomely dead cabinet.
Going to this amount of work to sandwich a cabinet sounds like the right place to use... sand.
Mortite is not forever stuff in my experience - it hardens over time, and it is pretty reflective above some arbitrary frequency. Best used for temporarily sealing leaks. It sticks ok to paint, will stain some materials, probably doesn't matter here though.
Mortite is not forever stuff in my experience - it hardens over time, and it is pretty reflective above some arbitrary frequency. Best used for temporarily sealing leaks. It sticks ok to paint, will stain some materials, probably doesn't matter here though.
Definately not for art, it is actually an adhesive clay. If it gets dirty it loses its stickiness(just like tape), but when fresh can be used for immobilizing parts on a desk, hanging light objects etc. But I would not trust it to stay attached to vibrating walls indefinately.
They make sheets of material exactly for the application in question, i dont remember if they are self adhesive or if they glue on like veneer. These sheets however are actually designed for reducing panel resonance, I belive they're the same ones use on newer cars.
I dont remember the post but it is somewhere on this site, the effectiveness/availibility/cost are discussed.
I've never lined an enclosure with it,that might be a bit hard to do,a single 2mm strip at a time!
I have used it to dampen baskets and around the magnets and stuff on subwoofers,and it does work quite well for that!
I've also used silicone in a pinch,it works well too!
I also usually use it to seal the speaker to the box,just a bead around the rim. Works well,is non-hardening,and is easy to remove later,if you want to swap drivers.
I have used it to dampen baskets and around the magnets and stuff on subwoofers,and it does work quite well for that!
I've also used silicone in a pinch,it works well too!
I also usually use it to seal the speaker to the box,just a bead around the rim. Works well,is non-hardening,and is easy to remove later,if you want to swap drivers.
Ok, I'll give you my secret: "roof repair tape" it's VERY sticky asphalt/tar type stuff with an aluminum foil backing and comes in various size rolls. If you're going to stick it to wood I recomend putting a coat of contact adhesive on the wood first (let it dry first too) and it will REALLY stick permanently, very well. I know I'm not the only one that uses this stuff but I did use it before I knew about anyone else using it
Oh, Mortite will not take very long to fall off of wood that it's stuck to, it really only stays well stuck into crevices, generally... You do have to love the name though! More tite, heheheh! (think Beavis and Butthead)
Oh, Mortite will not take very long to fall off of wood that it's stuck to, it really only stays well stuck into crevices, generally... You do have to love the name though! More tite, heheheh! (think Beavis and Butthead)
Cabinet damping has been extensively discussed on the old Bass List (now the diyspeaker forum). One of the prolific experimenters, Ed Heath, has used oil based modelling clay (only oil based !) for years. It never hardens, even after years and years in place, doesn't peel off if firmly pressed into place originally, and if additional mass is deemed to be needed, you can add lead birdshot. You just mix it together and roll it out to the desired thickness (don't use your wife's rolling pin!) and then press firmly into place using your fingertips, which can provide you with a method of ID'ing your stolen speaker. OTOH, it may end up heavy enough that few thieves will bother :^)
If you are a suspenders and belt type, roll out the clay on hardware cloth or screendoor mesh and staple as well as pressing it into place.
I'm told you can get oil-based modelling clay for around $1 a pound from craftstore outlets, but you'd have to check it out for yourself.
Hope this helps,
TerryO
If you are a suspenders and belt type, roll out the clay on hardware cloth or screendoor mesh and staple as well as pressing it into place.
I'm told you can get oil-based modelling clay for around $1 a pound from craftstore outlets, but you'd have to check it out for yourself.
Hope this helps,
TerryO
Rope caulk works well on thin material because it's as massive as that which is being damped - not the case for the cabinet walls.
Constrained layer damping is better for that. I've had good results by bonding a layer of sheet metal to the inside cabinet walls with Liquid Nails for Projects (or whichever type says "stays flexible").
"roof repair tape" it's VERY sticky asphalt/tar type stuff with an aluminum foil backing and comes in various size rolls. "
That sounds good, I'll try that.
BTW, you don't need to cover the entire panel, as it's most effective where there's the most motion to damp, near the center.
Covering 75% of the length and width between braces should be ample.
Constrained layer damping is better for that. I've had good results by bonding a layer of sheet metal to the inside cabinet walls with Liquid Nails for Projects (or whichever type says "stays flexible").
"roof repair tape" it's VERY sticky asphalt/tar type stuff with an aluminum foil backing and comes in various size rolls. "
That sounds good, I'll try that.
BTW, you don't need to cover the entire panel, as it's most effective where there's the most motion to damp, near the center.
Covering 75% of the length and width between braces should be ample.
For what it's worth
I put 1/4" +/- of modeling clay on the backs of the drivers and the entire inside surface of a pair of Avent IIs in the Mid 70s. I could compare them to two others I had (Quadraphonic was big back then). The difference in clarity was amazing. How long did it last? Well... the foam surrounds have long since rotted but the clay is still fine.
I put 1/4" +/- of modeling clay on the backs of the drivers and the entire inside surface of a pair of Avent IIs in the Mid 70s. I could compare them to two others I had (Quadraphonic was big back then). The difference in clarity was amazing. How long did it last? Well... the foam surrounds have long since rotted but the clay is still fine.
When using something like the roof repair tape, be sure that the gassing-off will not have adverse effects on your drivers. The fact that it is self adhesive indicates a high solvent count. Since these solvents are volitile and may also be aromatic I'd be careful. The foil will prevent the gas-off from taking place as quickly but will prolong it. Not only that but if used in a ported cabinet, you might smell it for quite some time.
Are you sure there's nothing else a little more suited to doing this?
If you do use it, Critofur is right about the use of contact adhesive. All of the peel and stick roofing membranes use it now as a primer. The darn stuff just no stickum without it. Funny thing is, the contact stuff they use is water based and the peel and stick is anything but. I would also consider using a tape of some kind to seal the edges to the cabinet and further delay the gas-off.
Are you sure there's nothing else a little more suited to doing this?
If you do use it, Critofur is right about the use of contact adhesive. All of the peel and stick roofing membranes use it now as a primer. The darn stuff just no stickum without it. Funny thing is, the contact stuff they use is water based and the peel and stick is anything but. I would also consider using a tape of some kind to seal the edges to the cabinet and further delay the gas-off.
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