|Multi-Way Conventional loudspeakers with crossovers|
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|1st December 2020, 02:30 AM||#271|
Join Date: Nov 2019
I assume it is something like this, https://www.amazon.com/ROSEROSA-Prof.../dp/B07Z32Z8WB
Though what is more typically used in speakers is the same stuff as cars, https://www.amazon.com/Noico-deadeni...dp/B00URUIKAK/
That is the 80mil version, there are thinner butyl layers like 50mil out there as well. I have yet to build a speaker box with the butyl, but cars and right behind my headboard of my bed outside is the water heater box. Really thin galvanized metal that just made an incredible racket in the wind and rain. Use that to fix it up right. Sound is reduced and what is left is lower pitch.
|10th December 2020, 12:12 PM||#274|
Join Date: Oct 2018
I've been going off this for designing a new system: https://qualia.webs.com/newdampingfactors.htm
Which, when the info is put in order (and taking out anything over 300hz) looks like this:
material frequency damping factor
tungsten loaded putty 80 0.725
'Permali' 18mm 220 0.688
'Permali' 6mm 250 0.671
'Newplast' 160 0.635
bentonite filled resin 48 0.618
'Panzerholz' 150 0.599
lead filled resin 100 0.592
bentonite powder filled resin 100 0.518
glass 'Butacite' laminate 150 0.391
'Pyrotek' 6mm 100 0.376
recycled rubber crumb 109 0.348
glass 'Sentryglas' laminate 247 0.317
Page Lacquer' acrylic over mdf 100 0.315
Plasticine' 77 0.304
Tungsten loaded putty is available at fishing supply places but too expensive for a bulk coverage. Good for small area decoupling though! Similarly, Permali and Panzerholz is very expensive - not to mention tough to source. So I don't think they are worth considering given the parameters of this testing.
However, bentonite filled resin looks very interesting (and goes looooww), resin (isophthalic, in this case) is relatively cheap and the bentonite for the non-powder version is standard cat litter. Also cheap, and available everywhere. If it's possible to pour a reasonable thickness in the gap of the enclosures, or even make a quick box out of it, that'd be fascinating to see the results. I've ordered some resin anyway, so I'll be trying it out soon...
If I can find a cheap source of tungsten powder, I'm tempted to try a resin with that in as well.
Anyone else have experience with these materials?
|16th December 2020, 11:50 PM||#276|
Join Date: Jul 2007
That is: a cheap complex material can be better than a simple expensive one.
Also note that a complex shape (a box, with holes and bracing) probably has massively different damping compared to a flat test panel. e.g. a bell and a gun will ring very differently, even if they are made of the same metal.
Unless you are after exoticism for its own sake, or in a bling competition with a millionaire, I can't see any situation where the expense would be worth the marginal volume reduction.
...but I'd rather be disappointed by $10 of materials than by $500 of materials
I've also done some building with a ply / bamboo laminate, because
1) bamboo has really good damping properties
2) it looks really good
3) it is good to work with (really hard surface, machines very cleanly).
4) the stuff I like comes as 2400 * 1200 * 5mm sheet. It is a single layer that is designed to be laminated to a base layer
5) that 5mm thickness is very forgiving of sloppy workmanship
6) it isn't crazy expensive like Panzerholz (I got 4 sheets for $500 Australian)
I like the aesthetics so much, I've done non-audio projects the same way (e.g. stripped old furniture and re-skinned with bamboo).
The only downsides are
- its hardness (and silicon content) makes it more work to cut, and it probably dulls tools more quickly
- it doesn't respond to tools exactly how wood does (e.g. you can't plane it with hand tools)
- the splinters are different to most woods (they can be really fine and really strong, so they go in deep and break off).
This edit signature thingy is seriously hard to find
|16th December 2020, 11:58 PM||#277|
Join Date: Aug 2006
hificompass doesn't say much about how he tapped the port and dampened the energy, maybe he will chime in.
Please help my waveguide and box construction research by donating to my gofundme via my website:Soma Sonus
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