I must confess I didn't even look at the product it was simply intended as an example of a nomogram from the manufacturer in the video. My reservations were prompted by Sorbothane which is expensive and heavily marketed at non-engineers for uses for which is not an optimum choice. For example, under speakers for isolation as mentioned by someone earlier. I suspect the lack of technical data is deliberate (the manufacturers will obviously possess this information) since if it was present potential customers might be put off by, for example, seeing peak losses way outside the frequency range they want.
I just went back to post #74 for the original source of the Decidamp suggestion. From the manufacturers site, Decidamp DC30 and DC06 are currently listed as CLD products.
Vibration Damping and Isolators, Pyrotek Solutions
Both are 2-component products and are recommended for metal or hard surfaces. From the data sheet pdf's, suggested thickness is 2mm for DC30 and 1mm for DC06. On the manufacturers product descriptions, it is by no means guaranteed, that these are suitable for the application discussed in this thread. The 2-component nature would make for a tedious preparation and use. OTOH they might work fine. We just can't know without testing.
Anyone spot a purchase resource for the decidamp stuff? I don't see a "BUY" link on the pyrotek website, and I don't see it in the usual spots on-line.
Decidamp is not specifically an Audio product. It's primary uses are automotive and architectural (from what I can gather). It seems you'd be more likely to spot it in hardware or construction supplies...
I still haven't located a Canadian outlet for it.
Looking at the video Douglas posted specifically where the square pieces are hung up and struck, I feel that the result wasn't as good as I got using polyurethane adhesive, the video didn't impress me. Granted, it's hard to be sure with a subjective comparison to something I did years ago.
A water based "goo" shouldn't necessarily make it unsuitable for timber. -After all common "white glue" (PVA-type) is the most common one used for wood, MDF and particle board.
You can check out Pyrotec's other stuff on Soundproofing Technical Data Sheets - Pyrotek
Towards the bottom one can find their "Subdue"-range. = Various plywood composites with a constrained layer in the middle. If one checks out the material descriptions and the loss factor diagrams, it shows that an increased ratio of constrainer layers versus constrained layer gives an improved loss factor. There also diagrams for lossfactor shown for different frequencies
When they write: "The inner core is thin, dense and made from a specially developed polymer with superior damping properties to improve transmission loss and reduce structure borne noise.", my guess is that the constrained layer is either butyl- or neoprene based as these 2 show good damping properties compared to other types of rubber, while at the same time don't cost fortunes like viton would.
If one has problems with resonance and "booming" from a light weight wooden floor and wants to isolate speaker cabinet vibrations, the info sheet they have on Getzners Sylomer material contains very good theoretical info. (To be on the safe side; always aim for a resonance in the isolation pad which is at least 1 octave lower than what the speaker can play. https://www.pyroteknc.com/dmsdocument/82/Pyrotek-Getzner-Sylomer-TDS-114IP.pdf )
You can check out Pyrotec's other stuff on Soundproofing Technical Data Sheets - Pyrotek
Towards the bottom one can find their "Subdue"-range. = Various plywood composites with a constrained layer in the middle. If one checks out the material descriptions and the loss factor diagrams, it shows that an increased ratio of constrainer layers versus constrained layer gives an improved loss factor. There also diagrams for lossfactor shown for different frequencies
When they write: "The inner core is thin, dense and made from a specially developed polymer with superior damping properties to improve transmission loss and reduce structure borne noise.", my guess is that the constrained layer is either butyl- or neoprene based as these 2 show good damping properties compared to other types of rubber, while at the same time don't cost fortunes like viton would.
If one has problems with resonance and "booming" from a light weight wooden floor and wants to isolate speaker cabinet vibrations, the info sheet they have on Getzners Sylomer material contains very good theoretical info. (To be on the safe side; always aim for a resonance in the isolation pad which is at least 1 octave lower than what the speaker can play. https://www.pyroteknc.com/dmsdocument/82/Pyrotek-Getzner-Sylomer-TDS-114IP.pdf )
Good point. I was distracted by most of the suggested applications are to impervious surfaces. The links at last provide some objective analysis to consider. Plenty to digest. Thanks Adhoc1.
Their Subdue@M product looks just like what we have been discussing. In fact, they state in the Technical Data Sheet, Applications,
" Used in the audio industry to construct high quality speaker enclosures"
The two constraining layers are marine ply. Be prepared for sticker shock on pricing.
I'm having the same problem. I keep going back to my first big build and I'm thinking my memory might be just a wee bit romanticised.
I will say that watching that video really hit a big chord with me as the way he describes the CLD process is almost exactly the way I remember coming to it ... Except I used GE Silicone sealer.
In fact, I showed that video to an old friend of mine and his comment was: "Oh look, he's reinvented your speakers."
It's kinda hard to be objective with that going on...
Hmmm ... guilty as charged.
I've been using sobothane disks under speakers for a couple of years now. But what I don't think people fully understand is that it's not for me and my friends/clients... it's for their neighbours. While it makes little enough to be no difference inside the listening room, the benefit is that it prevents mechanical coupling of vibrations into the structure of the building, limiting transmission of "one note bass" that is so common in apartments and condos.
I've never been silly enough to claim it has any other beneficial effect.
😕 I said "Objective" not "Objectionable"... although some will likely claim I'm both. 😀
Lol. What I meant was.. objective means without bias, but it also means with proof, ie measurements.
I'm going to give this one last bump, to ask one more question...
Is there any real interest in this box construction technique, that would drive a semi-formal research project?
I won't be starting on my build for a while yet, still a lot of decisions to be made and, well, a budget to accommodate but if someone wants to set up a repository for our aggregated knowledge on CLD in speakers, I'll be more than happy to contribute my notes, once I start building...
Thank you all for your replies and contributions so far.
Is there any real interest in this box construction technique, that would drive a semi-formal research project?
I won't be starting on my build for a while yet, still a lot of decisions to be made and, well, a budget to accommodate but if someone wants to set up a repository for our aggregated knowledge on CLD in speakers, I'll be more than happy to contribute my notes, once I start building...
Thank you all for your replies and contributions so far.
I have a 3-axis accelerometer that is still in its box unused. I am tempted to set it up and acquire some data similarly to the test in the video you posted. I would make up 30x30cm (12"x12") constrained layer panels, with overall ~25mm (1"). In the first instance, plywood vs mdf and glazing silicone vs solid. Maybe I can source a test piece of Subdue@M from Pyrotek for comparison. I am busy with other projects, so it won't happen soon, if at all.
I am planning a test setup for speaker building materials.
Basically it's a capable fullrange speaker in a sealed concrete box with a rear volume of maybe 20 liters, and a front volume of half or a third of that. The front volume then gets covered with the test specimen - one foot square seems a meaningful size here.
I am planning to make the cover a mitered half-box, so it is pretty close to a real construction.
I'll then run sweeps and measure the sound emanating from the exchangeable panel. Since the massive concrete box (maybe an inch thick) will be far more impermeable, I hope to get useful results.
Basically it's a capable fullrange speaker in a sealed concrete box with a rear volume of maybe 20 liters, and a front volume of half or a third of that. The front volume then gets covered with the test specimen - one foot square seems a meaningful size here.
I am planning to make the cover a mitered half-box, so it is pretty close to a real construction.
I'll then run sweeps and measure the sound emanating from the exchangeable panel. Since the massive concrete box (maybe an inch thick) will be far more impermeable, I hope to get useful results.
