Hi y'all. I'm (slowly) building my first ever diy (tower) speakers and I'm thinking of trying to add a CLD internally to prevent any panel resonances. I have no woodworking skills and my enclosures aren't that brilliantly constructed, (no rebates, biscuits, dadoes etc) im just going to use butt joints, screwed and glued. I'm using 24mm bb ply for the panels and 18mm MDF for 3 internal shelf braces. The baffle panels were cut by a CNC company for me with the cutouts rebated for the drivers.
Due to the less than optimal construction, I wondered if I could push the boat out with internal damping to improve overall results? My plan is to line the interior surfaces, with 2.3mm foil faced butyl sound deadening sheets and then glue a layer of class 5, 2.24mm lead sheet on that to form CLD. Would this be likely to have a worthwhile effect on cabinet vibrations? (I plan to apply it to the rear of the baffle too.)
Any opinions gratefully received!
Martin.
Due to the less than optimal construction, I wondered if I could push the boat out with internal damping to improve overall results? My plan is to line the interior surfaces, with 2.3mm foil faced butyl sound deadening sheets and then glue a layer of class 5, 2.24mm lead sheet on that to form CLD. Would this be likely to have a worthwhile effect on cabinet vibrations? (I plan to apply it to the rear of the baffle too.)
Any opinions gratefully received!
Martin.
Well 'Constrained Layer Damping' two panel layers with the Green Glue in between. That takes some design and construction skill.
Placing butyl/lead sheets on the interior surface is not CLD.
Placing butyl/lead sheets on the interior surface is not CLD.
No opinions? Oh well, I'll go ahead and order the lead sheet and give it a go. I'm gonna use layers of closed cell foam, wool carpet underlay and loose wool wadding within the CLD and hope that this 'belt and braces' approach will have enough dampening effect to overcome any shortcomings in my speaker construction.
As a matter of interest, I'm using a pair of actively driven Dayton RS 180-4's wired in series at the top of my tower speakers and I'm making separate top mounted open backed enclosures for Dayton AMT PRO4's . They will also be similarly butyl & lead lined with layers of felt behind the drivers. That should hopefully prevent unwanted extra vibrations in the 1.5khz> band they Will be covering.
Martin.
As a matter of interest, I'm using a pair of actively driven Dayton RS 180-4's wired in series at the top of my tower speakers and I'm making separate top mounted open backed enclosures for Dayton AMT PRO4's . They will also be similarly butyl & lead lined with layers of felt behind the drivers. That should hopefully prevent unwanted extra vibrations in the 1.5khz> band they Will be covering.
Martin.
Oops, sorry speed skater, I didn't see your reply. It seems I haven't understood CLD too well. I thought the high mass of the Lead would work with a layer of butyl to contain the vibrations within my enclosures. The constrained layer will have to be more lossy than butyl then.
Martin.
Martin.
Thanks for your reply. I should have posted without using the term CLD which I assume means the constrained layer must be within the enclosure panels. I'm thinking about mounting the top part of the baffle that mounts the drivers (or the whole baffle) on a layer of butyl? Providing I can ensure its sealed, that could further reduce potential vibration.
Martin.
I'm in the process of lining my full range speakers with a second layer of code 5 lead. 3 mtrs worth. Iv'e already lined the insides of the cabinet with code 4 6mtrs worth £138 worth. I have the code 5 for the sandwich layer. The sound improves with sound projecting ffrom the drivers and not the side walls. Very defined sound and bass that is certainly lower and punchy.
Wow those are likely Heavy rascals.
Oddly I've yet to hear sounds emanating from the sides/backs etc of speakers.. at least by pressing my ears flat to their boxes.
Solving a Non exisitant problem?
Oddly I've yet to hear sounds emanating from the sides/backs etc of speakers.. at least by pressing my ears flat to their boxes.
Solving a Non exisitant problem?
Lead sheeting is certainly not cheap! I've already invested £800 on my first speaker build so I've just spent a modest £35 on some, 3mm lead sheet from Ebay to go over a 2.3mm buty/foil layer. CLD or not, I reckon I'll have some pretty well dampened enclosures once I've added 30mm of wool underlay on the back wall & 10mm on the sides and roof plus long Fibre wool wadding in the remaining cavities. I'll have a sand bag in the bottom of my oversized enclosures. Hopefully spray contact adhesive will be OK to glue the lead to the foil backing of the butyl layer? My 24mm BB plywood cabinets with bracing already seem good with a knuckle wrap test so I have high hopes for the end result once I've chucked in the kitchen sink's worth of damping?
constrained layer damping doesn't require the mass of lead - may even work better if the resonance is at higher frequencies if the soft layer is more lossy there
cross bracing damping is endorsed by Geddes, used in his relatively low mass polyurethane modeling board walled speaker enclosures
cross bracing damping is endorsed by Geddes, used in his relatively low mass polyurethane modeling board walled speaker enclosures
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Hi, do you mean Geddes recommends having damping layer between the enclosure walls and the braces?
no the cross braces are split, damping layer goes between the halves from each side so that it shears
instead of a mid panel, wall to opposite wall wood dowel bcross brace, think piston shock absorber
instead of a mid panel, wall to opposite wall wood dowel bcross brace, think piston shock absorber
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Hmm, I've built. my first speaker with 3 shelf braces but I can't see how I can modify them with a damping layer. Hopefully the cabinet resonances will be sufficiently damped without brace damping? 
The lead certainly working in my speakers. Sounds tighter & more controlled. The enclosures have standard upholstery foam on all internal areas except the front baffle.
As I like to play my music concert level loud, I can if I firmly press my ear to the cabinet some mid frequencies. My understanding is that these freq can be eliminated by using rockwool fiber glass sheets. Is this correct?
I think the more the cabinet is damped the more focused the sound is that is supposed to arrive out of the drive units.
As I like to play my music concert level loud, I can if I firmly press my ear to the cabinet some mid frequencies. My understanding is that these freq can be eliminated by using rockwool fiber glass sheets. Is this correct?
I think the more the cabinet is damped the more focused the sound is that is supposed to arrive out of the drive units.
I hope so, Nautilusdave!! I was showing off my laboriously hand filed chamfers for rear of speaker breathing into the enclosure! Here's the front.
An externally hosted image should be here but it was not working when we last tested it.
Here's some experimental CSD (Confined Schroedinger Layer) Fur based damping I'm working on!
An externally hosted image should be here but it was not working when we last tested it.
I'm using a lead sealant adhesive from Tool Station. You need a well vented area when installing this sealant.
Great to see you put me right regarding fixings. aLooking good...🙂
Great to see you put me right regarding fixings. aLooking good...🙂
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