We don't talk the same thing at all imho.
I doubt your car base layer (car's body) is wood or derived material and it is easier to tame sheet metal in low end than a structure using wood ime ( without even using CLD but only 'simple regular contact damping', but at weight increase as a compromise): freq where resonance happens are not the same and in case of wood it's right into the range where most first harmonics are located which can be a real issue regarding offence created. Metal is usually either way higher or lower in freq from case i encountered.
I could give you other example ( like yours involving sheet metal) where CLD was highly effective in studio construction ( structural acoustic) i've been involved into, but i think in case of a loudspeaker box it's not as simple as treatment of sympathetic resonance, or soundproofing a structure using dual leaf 'cld' ( where this is more about material impedance mismatch at different freq range imho...). Or effects like plate reverbs...
Those issue about box looks deceptively simple, they often seems easy to treat but are often more vicious than a first sight analysis would tell.
We have some members which were structural engineer and have far more understanding in this field and could help way more understanding those issues and how to treat them than what our anecdotal evidence tought us (and i include mine into this).
@hifijim what's your pov on this?
I doubt your car base layer (car's body) is wood or derived material and it is easier to tame sheet metal in low end than a structure using wood ime ( without even using CLD but only 'simple regular contact damping', but at weight increase as a compromise): freq where resonance happens are not the same and in case of wood it's right into the range where most first harmonics are located which can be a real issue regarding offence created. Metal is usually either way higher or lower in freq from case i encountered.
I could give you other example ( like yours involving sheet metal) where CLD was highly effective in studio construction ( structural acoustic) i've been involved into, but i think in case of a loudspeaker box it's not as simple as treatment of sympathetic resonance, or soundproofing a structure using dual leaf 'cld' ( where this is more about material impedance mismatch at different freq range imho...). Or effects like plate reverbs...
Those issue about box looks deceptively simple, they often seems easy to treat but are often more vicious than a first sight analysis would tell.
We have some members which were structural engineer and have far more understanding in this field and could help way more understanding those issues and how to treat them than what our anecdotal evidence tought us (and i include mine into this).
@hifijim what's your pov on this?
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I hesitated to offer an opinion, since these threads on cabinet bracing and damping usually spin into a heated argument...
But I am going to give an opinion anyway. A speaker cabinet which is simply an unbraced box is relatively simple to analyze or model with a FEM. A cabinet which is well braced and has added structural damping is complicated to analyze. Not impossible by any means, but complicated, and in this case complicated means a lot of effort by someone who knows what they are doing. This complexity means that most one-off DIY cabinets will not ever be correctly modelled with a FEM.
Because of this, all we have to rely on is generalized rules and guidelines. These rules and guidelines may work extremely well for some cabinet designs, and then not work so well on another.
There have been successful low-signature cabinets built with a high-damping CLD approach. There have also been successful low-signature cabinets built with high rigidity and no added damping. I am sure there are examples of each type which were not so successful. If this topic was simple, we would all be doing it the same way, and it would be the right way. It's not, and we are not...
I build my cabinets to be stiff and rigid. If I am going all out on performance, I add additional butyl rubber damping to the interior. This is a pain in the rear to do, so I only do it when I am shooting for high performance.
j.
But I am going to give an opinion anyway. A speaker cabinet which is simply an unbraced box is relatively simple to analyze or model with a FEM. A cabinet which is well braced and has added structural damping is complicated to analyze. Not impossible by any means, but complicated, and in this case complicated means a lot of effort by someone who knows what they are doing. This complexity means that most one-off DIY cabinets will not ever be correctly modelled with a FEM.
Because of this, all we have to rely on is generalized rules and guidelines. These rules and guidelines may work extremely well for some cabinet designs, and then not work so well on another.
There have been successful low-signature cabinets built with a high-damping CLD approach. There have also been successful low-signature cabinets built with high rigidity and no added damping. I am sure there are examples of each type which were not so successful. If this topic was simple, we would all be doing it the same way, and it would be the right way. It's not, and we are not...
I build my cabinets to be stiff and rigid. If I am going all out on performance, I add additional butyl rubber damping to the interior. This is a pain in the rear to do, so I only do it when I am shooting for high performance.
j.
Did I miss your example of constrained layer damping? I did look! I don't understand how your comment about damping without heavy bracing relates to the discussion of CLD.
I think Krivium is commenting that CLD is vibration damping, but not all vibration damping is CLD. In fact, most methods of vibration damping are not actually CLD. Constrained layer damping is taking a very resonant material like a thin sheet of metal and dramatically reducing it's resonance by layering 2 pieces of the resonant material with a viscous material inbetween. So a construction with 3/4" MDF + 3/4" Plywood as shown above produces a damping effect, but it isn't really a CLD, since the wood materials are already self-damping to a large extent.
To be precise, I am considering a CLD panel to be a panel where the majority of the damping comes from the vicous layer. A thick assembly made from self-damping materials like wood is primarily damped by the wood. A constrained layer might contribute some damping, but the performance of the assembly would not change significantly if the constrained layer were removed...that's the "engineering" part of my previous comment!
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Any suggestions on the "best" practical test of panel resonance? I think I should establish a frame of reference for comparing various materials, so I can tell if any CLD panel I make is actually better than any other standard construction material.
I had the idea of using an "exciter" on test panels, and then taking sweep measurements in REW. And yesterday I had a handful of exciters fall into my lap for free! They are Dayton DAEX25Q-4.
My theory is that these exciters will inpart a controlled amount of energy into the panel, so measuring the acoustic energy output from each panel will tell give us a good indication about each panel's characteristics.
And I'm hoping this data will make it possible to directly compare materials with very different properties.
The part I haven't finalized is the actual construction of the test rig. The exciters have adhesive pads to attach to a panel, which isn't ideal. Instead of sticking them to the panel, I was thinking I could mount the exciter face up and lay the panel on top of the exciter? It seems like the simplest way, but let me know if you have any suggestions.
I had the idea of using an "exciter" on test panels, and then taking sweep measurements in REW. And yesterday I had a handful of exciters fall into my lap for free! They are Dayton DAEX25Q-4.
My theory is that these exciters will inpart a controlled amount of energy into the panel, so measuring the acoustic energy output from each panel will tell give us a good indication about each panel's characteristics.
And I'm hoping this data will make it possible to directly compare materials with very different properties.
The part I haven't finalized is the actual construction of the test rig. The exciters have adhesive pads to attach to a panel, which isn't ideal. Instead of sticking them to the panel, I was thinking I could mount the exciter face up and lay the panel on top of the exciter? It seems like the simplest way, but let me know if you have any suggestions.
If you need something quick you could hold one edge of a panel up so the panel is at an angle, and drop a hammer on to it from a short distance. It should be obvious comparing one to the other.
Your test sounds good. Looking forward to seeing your results.
Your test sounds good. Looking forward to seeing your results.
Do you know how it compares with an FRP composite sandwich? This is the board material between two fibreglass/epoxy skins. How does CLD and FRP compare with shifting the resonance away from the audio bandwidth, and does adding the two extra layers in either system provide any other benefits?
My bet is on FRP composite sandwich
Take a ply board. It has some flex. Now add a heap of soft mass to it. Is this CLD? With any movement of the panel, there will be start up and stopping inertia types of things to overcome. How sensitive are you to perceiving very low bass resonance? My old Holden Adventra was amazing to lean back on after a long drive with all the Dynamat in the panels. Great massage. On the other hand, the last centre console that I built had the floor, saddle seat, transom and stringers as one monocoque FRP structure in 8mm ply. NVH from the outboard and chop did not transmit to a non-cushioned seat top or steering wheel
In the near future, I have to substantially increase the subs in the current Subaru XV. I have been thinking about turning the panels into FRP composite by injecting expandable foam between external and internal panels where suitable and internal glass/epoxy skins in other areas where there is no suitable internal side panel
So what actually happens to a naked panel ina speaker box? How much bellows action vs wiggles running through the panel? Both are shifted up in an FRP composite sandwich. The thing about the wiggle wave type of vibration is that it travels through braces too. These should be reduced in mass and made stiffer, such as the frame and stringer matrix in FRP composite sandwich. I came up with a system of drop stitching panels together using through dowels to reduce brace mass. Carbon tubes injected with expanding foam would make the best dowels, but a wooden dowel wrapped in uni glass cloth and epoxy is very good too
I made a career out of tuning how a wave passes through a material, and still can't understand the science behind CLD. Adding weights along a length of stiff material was an ideal way of increasing vibration passing up the material and softening the action down. Can anyone explain how CLD actually works?
Randy, you should search this forum. It has been explained before. Something about the vibration causing a shearing action on the softer layer between the outer skins. I seem to remember it was found that thin layers worked well - it was not necessary to go thick. The BBC had some papers from back in the day where they explained their version of CLD, but I can't remember where I've seen them.
If this has been covered above I apologise as I haven't read all the thread.
If this has been covered above I apologise as I haven't read all the thread.
I am going to make some composite panes to test. I previously tried the "tap" test with carbon fiber/ MDF and carbon fiber/ plywood panels. Also carbon fiber over foam. It wasn't a very good test, but the MDF with carbon seemed to compare similarly to plain plywood. And the carbon fiber over foam board seemed to transmit vibrations rather than damp them.
I'm also going to try stuff like plywood/ balsa/ plywood panels, along with the other stuff.
I haven't had much success with damping, I'm guessing that the damping medium has been too stiff - the next time I try it, I will use felt. I've made some speakers out of 6mm MDF, and I will add thin felt to the outside, then glue thin ply (3.4mm approx), hopefully this will be soft enough, and act like double glazing. The best success I've had in taming vibrations was to make a very thin, light and stiff cabinet (about 1kg for 8 litres) so it's resonant frequency is much higher than the bass driver, that only goes up to 250 Hz.
I've also tried a layer of felt, with carpet tile glued to it, on the inside, but it's on such a small area, it's difficult to tell how effective it is.
I've also tried a layer of felt, with carpet tile glued to it, on the inside, but it's on such a small area, it's difficult to tell how effective it is.
I actually tried this some years ago, using a swedish product which i could source locally, i glued 3 layers of plywood together with this noisekiller stuff but never finished the project.
The "knock-test" didn't convince me that it was worth the effort but at the same time they recommended a certain pressure when gluing it together that I had no way of achieving at home. If I had the necassary tools etc it might have been worth it just for the sake of it since you still have to glue the sheets together and you might aswell do it with the constrained layer technique.
The "knock-test" didn't convince me that it was worth the effort but at the same time they recommended a certain pressure when gluing it together that I had no way of achieving at home. If I had the necassary tools etc it might have been worth it just for the sake of it since you still have to glue the sheets together and you might aswell do it with the constrained layer technique.
Attachments
Would you mind some further details? Let's dump MDF as a suitable substrate for FRP sandwich first. It is very heavy and light and stiff is desired
Ply thickness?
Which carbon cloth?
Cloth type is very important. As is the stringer matrix as spans increase. So is the fillet at the junction of two panels
Maybe the topic would be better served by first understanding what the panel faces. A working panel is one that is correctly fixed in place, the built box is a good test case and better than trying to clamp a test panel. Real results
The driver radiates wiggles through the material. This is killed by FRP sandwich (ina monocoque structure). This is like grabbing an edge and jiggling. Then there is the physical impact component. This doesn't really get amplified, but rather the structure is transparent to it. This is the driver diaphragm output over air and I have come to believe the beauty behind well done BR and PR systems to pass that impact through via the resonant stage
I have read them but haven't been able to reconcile. Seems counterintuitive after slowing down way too many carbon tubes
I should mention, to keep in context, we can think a tapered hex tube made of FRP slices instead of a tube. A wiggle will travel up this and kick the hand holding the end. Now flare that thicker end and the wiggle has less power to finish its run and kick. This is what a fillet does inside the panel junction too
Building on from what I am picking on. In a double glaze, what is happening to the internal skin? In a speaker, is that going to bounce back?
But I think that you are on the right track with the super light cabs. I also feel that PVC foam with only paper skins would give even better results than very thin ply in conjunction with my drop stitches
Coming back to this now to hopefully successfully help make some connections
The tap is an impact and will pass through. My test show that if tap dampening is needed than the best material is HDPE but will have the worst wiggle and fixed with material thickness. It has a really sweet sound if done right but needs specialist skills to build a box with
Tap a stiff item and it will tap forward. Make use of that forward by placing a resonant system at the out
How about now bringing in the dampening wool thread topic into this too. Maybe balance the tap out with a pad of layered cloth on the panels instead of wool stuff. Same with the layered pad on the back of a PR or some wool in the port entry of a BR. Might clean the mud out while managing the impact types, but maybe it's the painkillers talking! But I have run a great many materials between hand and FRP to see what allows the kick to come through hard at that end
Randy you have not been able to get what CLD is mostly because people doesn't get what it's about and mix with other approach like multi layer damping... as can be seen from many answers given in here, here is a more industrial definition :
https://www.vibratec.org/application-area/industry/constrained-layer-damping/
The fact is you can use whatever material as basis, but you then need to find a viscoelastic layer which act as it should with the given base material... and With wood derived material as mdf it's not easy to find and/or not cheap at all : E.A.R. had such products ( isodamp) but it was almost impossible to source for diyers, at least in EU. It was used in one Sony flagship loudspeaker, and the patent is accessible but it's not easy build technique for sure...
Sometimes only a glue is nescessary to reach efficient sheer dissipation, what E. GEDDES ended up doing with Summa in a 'matrix CLD approach' ( CLD over bracing), as Kef is doing...
https://www.vibratec.org/application-area/industry/constrained-layer-damping/
The fact is you can use whatever material as basis, but you then need to find a viscoelastic layer which act as it should with the given base material... and With wood derived material as mdf it's not easy to find and/or not cheap at all : E.A.R. had such products ( isodamp) but it was almost impossible to source for diyers, at least in EU. It was used in one Sony flagship loudspeaker, and the patent is accessible but it's not easy build technique for sure...
Sometimes only a glue is nescessary to reach efficient sheer dissipation, what E. GEDDES ended up doing with Summa in a 'matrix CLD approach' ( CLD over bracing), as Kef is doing...
I haven't decided what panels I will try. I am open to suggestions.
I guess the first step is to validate the test method. Hopefully I'll get a start on it this weekend. If results seem to make sense, then I'll make experimental panels based on the initial results. I have a variety of carbon fiber, kevlar, and fiberglass materials to play with.
Regarding MDF, my personal philosophy is that it doesn't make sense to make big changes without having a clear reason/ benefit from doing so, and MDF is really the standard material for hifi speakers. I'm not making any statement about whether or not MDF is good for speakers, but most speakers, including the ones I've made, are made from the stuff. So MDF is an important reference to maintain throughout any testing of cabinet materials.
As an aside, it might be interesting to test different types of MDF, because there are actually quite a few different types, although the different types are difficult to get ahold of outside of a commercial setting...
For me, the purpose of this experiment is to decide if there is a benefit to making the cabinet out of something other than MDF. So it must be included.
I don't have any photos, sorry.
A couple of decades ago I made several 1 foot square constrained layer damped panels. Two .5" layers; two .75" layers; one layer of each; three .5" layers; and two .75" layers with a .5" layer in between. Also made a couple of panels which were multiple layers glued together with wood glue (no constrained damping layer; a single-layer .5" panel; and a single;layer .75" panel.
I suspended them and hit them with a mallet and listened to the sound. Whether that was sufficiently scientific or not, I cannot say. Here is my recollection:
All of the constrained layer panels sounded much, much more dead than any of the non-constrained-layer panels. The two-identical-layer CLD panels were the best, with the two .75" layers being slightly better than the two .5" layers.
And a little data!
The panels are all 11.5"x 11.5", and I used screws to attach the exciter to the center of each panel. And I suspended the panels on 2 wood blocks, with the exciter on the bottom. How I suspended the panel didn't seem to matter, so I went low effort!
And the measurement mic was approx 3 1/4" above the surface if the panels.
My initial evaluation is simply to take the average SPL from 100dB to 10k dB.
I got a surprise result, contradicting my preception. I added a layer of dynamat to a couple of the panels, and I was surprised by it's effectiveness. My subjective opinion was that it did absolutely nothing, but from my measurements it resulted in panel resonance of -6dB! (For the record, the dynamat was applied to a layer of masking tape, so I was able to peel it off and re-apply it to other panels. Not the best, but it allowed me to stick it to multiple panels.)
Does this suggest that dynamat is "actually" CLD? CLD is supposed to be a viscous layer between 2 rigid materials. Maybe the aluminum facing is actually rigid enough to sound waves to function as CLD? That is news to me!
I'll let you guys process the data and tell me how you interpret it. I split the measurements into 3 files due to the file size limit.
For me, it seems that my 7/16" thick CLD panel (3/16 ply, 1/16 urethane, 3/16 ply) was less resonant than the 3/4" solid panels. Subjectively with a knock test it sounded different, but I wasn't sure it was actually "better". Or atleast the average SPL from 100 to 10k was lower than the others!
I think I need to continue this by making fiberglass panels with urethane in the middle. And maybe throw in some carbon fiber?
The panels are all 11.5"x 11.5", and I used screws to attach the exciter to the center of each panel. And I suspended the panels on 2 wood blocks, with the exciter on the bottom. How I suspended the panel didn't seem to matter, so I went low effort!
And the measurement mic was approx 3 1/4" above the surface if the panels.
My initial evaluation is simply to take the average SPL from 100dB to 10k dB.
I got a surprise result, contradicting my preception. I added a layer of dynamat to a couple of the panels, and I was surprised by it's effectiveness. My subjective opinion was that it did absolutely nothing, but from my measurements it resulted in panel resonance of -6dB! (For the record, the dynamat was applied to a layer of masking tape, so I was able to peel it off and re-apply it to other panels. Not the best, but it allowed me to stick it to multiple panels.)
Does this suggest that dynamat is "actually" CLD? CLD is supposed to be a viscous layer between 2 rigid materials. Maybe the aluminum facing is actually rigid enough to sound waves to function as CLD? That is news to me!
I'll let you guys process the data and tell me how you interpret it. I split the measurements into 3 files due to the file size limit.
For me, it seems that my 7/16" thick CLD panel (3/16 ply, 1/16 urethane, 3/16 ply) was less resonant than the 3/4" solid panels. Subjectively with a knock test it sounded different, but I wasn't sure it was actually "better". Or atleast the average SPL from 100 to 10k was lower than the others!
I think I need to continue this by making fiberglass panels with urethane in the middle. And maybe throw in some carbon fiber?
Try PVC foam with glass/carbon skins, but only use unwoven fabric (stitched stuff)
Is it a real test if the ends aren't fixed and filleted? Even a batten in the seam works as fillet somewhat
Regarding MDF
Real wood veneer on both sides is a really good approach. Veneered and cut bevel to be brought together. MDF works with 'thickness for stiffness' just like HDPE
Skins
If you do have materials like glass and carbon fibre on hand, then I suppose you already know about things like uni and biax and stuff but if you don't then we can do a lil primer to get you pointed in the right direction
Are you able to also try 0.5mm aluminium skins if you use foam boards. These can be built up in layers and make an excellent structural skin too. Epoxy is plenty to stick them down
It still feels wrong to waste driver output by viscous type dampening when a rigid monocoque can direct most of that to a resonant stage. Feels like building in a loss or inefficiency
Sadly real wood is a bad idea: it's living material ( humidity make it expand contract) and the grain orientation ( fiber orientation) gives weakness point in comparison to processed wood materials like mdf or ply ( which aren't totally protected against this either... check Wesayso towers translam adventure for a real life example).
Mdf can works differently than 'thickness for stiffness' but it have serious disadvantage in comparison to plywood ( it's fragile and doesn't like direct impact. Reason why 99% P.A. and live oriented box are made from ply).
Aluminium skins are a very good idea imho. Issue is how to assemble the CLD in a final box (Tig Welding?). And cost.
I disagree about your last sentence as you seems to forget that in CLD we try to dampen a very rigid and supposedly lightweight system ( it's relative: a supertanker deck is not really lightweight at our scale, but at the one of the vessel... 😉 ).
As such the frequency at which reasonance happen should be very high in frequency given size of a 'typical' cabinet. We could assume/expect way higher than anything a direct radiating driver is able to produce frequency wise. So we would not loose anything regarding efficiency. And for higher freq then you can decouple the driver from the box as energy is relatively low and it would make the driver 'floating' above the stucture, almost zero transmission...
Another thing to think about is that one of the theorical ideal about a loudspeaker is it should 'float' into the air. To approach this in studio we structurally decouple the box from the room using different approach ( either through visco elastic pads, springs,...) but usually right under the lower audio bandwidth or at the edge of it( circa to 5hz for the most efficient ones, sometimes higher with visco elastic mterials up to 30's/40's ).
My experience is the reproduction doesn't suffer of this, quite the contrary: secondary emmissive area are tamed/quiet ( parts of walls, floor, ceiling) which give a higher level of detail as direct sound is less masked. Expect the same thing from a better box regarding the absence of resonnance.
Mdf can works differently than 'thickness for stiffness' but it have serious disadvantage in comparison to plywood ( it's fragile and doesn't like direct impact. Reason why 99% P.A. and live oriented box are made from ply).
Aluminium skins are a very good idea imho. Issue is how to assemble the CLD in a final box (Tig Welding?). And cost.
I disagree about your last sentence as you seems to forget that in CLD we try to dampen a very rigid and supposedly lightweight system ( it's relative: a supertanker deck is not really lightweight at our scale, but at the one of the vessel... 😉 ).
As such the frequency at which reasonance happen should be very high in frequency given size of a 'typical' cabinet. We could assume/expect way higher than anything a direct radiating driver is able to produce frequency wise. So we would not loose anything regarding efficiency. And for higher freq then you can decouple the driver from the box as energy is relatively low and it would make the driver 'floating' above the stucture, almost zero transmission...
Another thing to think about is that one of the theorical ideal about a loudspeaker is it should 'float' into the air. To approach this in studio we structurally decouple the box from the room using different approach ( either through visco elastic pads, springs,...) but usually right under the lower audio bandwidth or at the edge of it( circa to 5hz for the most efficient ones, sometimes higher with visco elastic mterials up to 30's/40's ).
My experience is the reproduction doesn't suffer of this, quite the contrary: secondary emmissive area are tamed/quiet ( parts of walls, floor, ceiling) which give a higher level of detail as direct sound is less masked. Expect the same thing from a better box regarding the absence of resonnance.
-6db is not bad at all but from what i've seen it's possible to achieve way more when 'optimised' ( seen -24db for sheet metal used as outer shell in a studio which were sympathetically resonant with street noises ( trucks) cirac 40/50hz).
It might have been a result of a cld created or just result of damping from multilayer approach, difficult to say and why i said previously multilayer and mismatching of impedance can be quite effective too ( wrt cld).
It's one receipe used by commercial brands for all in one CLD materials:
https://www.pyroteknc.com/products/decidamp/decidamp-cld-pro/
My recommendation for real wood veneer is for mostly cosmetic reasons, but I think you would be familiar with how well real wood veneer protects the edges of MDF cabs
To my way of thinking, MDF is just very thick paper. I don't mind the sound of an MDF cab at all and both of my fav speakers of all time are commercial units made with MDF covered in cheap vinyl
Must make the point that I enjoy effected bass and MDF and HDPE sound nicely warm to me
This where we mix and match. As an example, the detail that I showed in the CAD stage of the Club Sandwich thread. There I showed how to terminate aluminium skinned panels with a bamboo baffle and rear panel. As well as aluminium to aluminium edge seams for side to side panels. It would be the same process to include a second lamination stage, but I think Dynamat might be too much
How about this schedule for a cab with a decent domestic bass. The schedule for Club Sandwich was 0.5mm alloy, 0.5mm alloy, 9mm PVC, 0.5mm alloy, 0.5mm alloy
This is a tough, light and rigid panel. How much CLD treatment would this need? How does this tap? How does this tap with a filleted internal seam?
How about some finesse instead of Dynamat? Add a coat of gasket maker and another 0.5mm alloy skin on the internal side. This skin edges can follow the curve of the fillets and tape over each other with a smear of the gasket make on the edge too as glue
Yes i get it about cosmetic Randy ( veneer). But this is not what i'm into, i'm ok with poor esthetic as long as it is effective from an audio pov ( at least this is the excuse i have about my poor skills with woodworking and imposing 'prototype' looking thingy into family's living room! Lol ).
About how to terminate panels, it's not easy as it could potentially change the way a CLD behave... I've far more experience in acoustic structural build regarding this ( if you consider 'dual leaf' made of BA18/viscoelastic material/BA13 for each leaf to be a cld, which i do...) and i can tell by experience a single (relatively big and long) nail could ruin a whole dual shell built around this principle! I would expect same thing in here.
Tbh, i contemplated this whole cld built for a long time ( member BON documented an impressive built around this maybe 10 years ago - or more.. - and it was intimidating to me). When i discovered E.Geddes talk about CLD bracing strategy and the fact he disclosed a 'dirty secret' used by many brands* to achieve same results as a whole CLD approach, i lost interest in the challenge it represent.
But that's me, i encourage THE BRAVE to follow their path if possible!
*(Tannoy used this in their D(ifferent)M(aterial)T(echnology) range, Kef into R series and LS50, i'm almost surei've seen something in the spirit in Genelec's and their metal enclosure last time i opened one...).
About how to terminate panels, it's not easy as it could potentially change the way a CLD behave... I've far more experience in acoustic structural build regarding this ( if you consider 'dual leaf' made of BA18/viscoelastic material/BA13 for each leaf to be a cld, which i do...) and i can tell by experience a single (relatively big and long) nail could ruin a whole dual shell built around this principle! I would expect same thing in here.
Tbh, i contemplated this whole cld built for a long time ( member BON documented an impressive built around this maybe 10 years ago - or more.. - and it was intimidating to me). When i discovered E.Geddes talk about CLD bracing strategy and the fact he disclosed a 'dirty secret' used by many brands* to achieve same results as a whole CLD approach, i lost interest in the challenge it represent.
But that's me, i encourage THE BRAVE to follow their path if possible!
*(Tannoy used this in their D(ifferent)M(aterial)T(echnology) range, Kef into R series and LS50, i'm almost surei've seen something in the spirit in Genelec's and their metal enclosure last time i opened one...).