# sound deadening inside sub box?



## QualitySound (Oct 27, 2015)

Has anyone compared sound deadening inside a sub box to no sound deadening inside a sub box, all else being equal? 

I was advised to use Black Hole Five or Black Hole Tile. Has anyone used those or other materials?


----------



## SkizeR (Apr 19, 2011)

have not tried or bothered but willing to bet its 100% useless for subwoofers


----------



## dgage (Oct 1, 2013)

What would be the point? The sound waves aren't getting through the box material although I guess that is an assumption based on most boxes being made of 3/4" plywood or MDF and of appropriate size for the driver. I've never heard of deadening materials on the walls being tested but can't imagine how it would make even a measurable difference. Now there have been many tests on adding dampening material to a subwoofer enclosure but even then the results are minor and very easily handled via DSP. Once you put the subwoofer enclosure in a car, the environment will affect the subs frequency response so much greater than whether you use dampening material or other tricks within the box.


----------



## QualitySound (Oct 27, 2015)

Thanks guys. It makes sense what you say. I was sort of just making sure.

And anyway, if sound deadening inside the sub box was worthwhile, it would probably be discussed in this forum, which does not seem to happen.


----------



## SkizeR (Apr 19, 2011)

gotta remember, traditional cld sound deadener is to treat resonance. if your sub box is resonating to the point where its audible, you have issues that deadener will not fix


----------



## diy.phil (May 23, 2011)

The Black Hole Five or Black Hole Tile might be the incorrect item to use(?). Usually it should be the Black Hole Stuff at: Blackhole / High Efficiency Dampening Products. I've seen this in some of the SiS or other installs here and actually want to try it. Or the Focal version(?)

Other times people use the fiberglass stuff (fluffy cotton-like or wool-like thing). Either material can be found inside many commercial and home speaker boxes. Just open the middle- and high-end speakers and we can see they line the entire inside walls or certain strategic places. 

The fluffy fiberglass stuff (yellow-gold color) used to be sold at Radio Shack for old school speaker builders. Or the same item is now the Home Depot Owens Corning R6.7 Unfaced Roll but this one is the Pink Panther pink only. Some of the online store sell the polyfill but I didn't like it when I tried it twice. The yellow or pink fiberglass ones actually work better but it's an itchy material when handling unlike the polyfil. The Black Hole Stuff should work too.


----------



## QualitySound (Oct 27, 2015)

diy.phil said:


> The Black Hole Five or Black Hole Tile might be the incorrect item to use(?). Usually it should be the Black Hole Stuff at: Blackhole / High Efficiency Dampening Products. I've seen this in some of the SiS or other installs here and actually want to try it. Or the Focal version(?)
> 
> Other times people use the fiberglass stuff (fluffy cotton-like or wool-like thing). Either material can be found inside many commercial and home speaker boxes. Just open the middle- and high-end speakers and we can see they line the entire inside walls or certain strategic places.
> 
> The fluffy fiberglass stuff (yellow-gold color) used to be sold at Radio Shack for old school speaker builders. Or the same item is now the Home Depot Owens Corning R6.7 Unfaced Roll but this one is the Pink Panther pink only. Some of the online store sell the polyfill but I didn't like it when I tried it twice. The yellow or pink fiberglass ones actually work better but it's an itchy material when handling unlike the polyfil. The Black Hole Stuff should work too.


Yeah, that's the site I was at too, and Black Hole is made by Orca, owner of Focal, Mosconi, Gladden, Raven, Illusion, it seems. 

The site says Black Hole Five is made specifically for lining sub boxes for SQ, unlike Black Hole Stuff or fiberglass or polyfill which I think is to make a small box function like a bigger box.

And Five is very expensive. I called a Focal dealer who said it's $35.00 for just one piece, 12" x 18". Wow. That would be a lot even if it's not snake oil.


----------



## Matthew Borgardt (Aug 13, 2016)

QualitySound said:


> Has anyone compared sound deadening inside a sub box to no sound deadening inside a sub box, all else being equal?
> 
> I was advised to use Black Hole Five or Black Hole Tile. Has anyone used those or other materials?


Using black hole 5 or any other deadening materials in a sub enclosure are unnecessary and a waste of money.
Bracing an enclosure is the key for best performance, one of the things that I do is pretension utilizing bracing... as you can see in this image the brace itself is about a 16th of an inch short by doing this,







I will pull in the wall of the enclosure causing it to have a resonant frequency out of the past band... and that is all you need.

Sent from my SAMSUNG-SM-N900A using Tapatalk


----------



## dgage (Oct 1, 2013)

And here is a panel resonance calculator. You'd really have to have a large enclosure though to have panel resonances close to the audible sub range. If you are trying to increase he panel resonances, the main thing I tell people is to put the bracing off center so you aren't making a pair of panels with the same resonance.

mh-audio.nl

David


----------



## Matthew Borgardt (Aug 13, 2016)

dgage said:


> And here is a panel resonance calculator. You'd really have to have a large enclosure though to have panel resonances close to the audible sub range. If you are trying to increase he panel resonances, the main thing I tell people is to put the bracing off center so you aren't making a pair of panels with the same resonance.
> 
> mh-audio.nl
> 
> David


Here one I like...

http://www.subwoofer-builder.com/freesoft.htm

Matt Borgardt


----------



## QualitySound (Oct 27, 2015)

Matthew Borgardt said:


> Using black hole 5 or any other deadening materials in a sub enclosure are unnecessary and a waste of money.
> Bracing an enclosure is the key for best performance, one of the things that I do is pretension utilizing bracing... as you can see in this image the brace itself is about a 16th of an inch short by doing this,
> 
> 
> ...


When you say, "Pull in the wall of the enclosure," do you mean you screw the wall to the brace to eliminate the 16th inch gap between the brace and wall? Or something else?


----------



## Rudeboy (Oct 16, 2005)

The constrained layer vibration dampers or liquid applied vibration dampers we use for sheet metal, composites and plastics are almost completely ineffective on thick substrates like MDF. If your box is properly constructed you shouldn't have to worry about panel resonance.

A relatively thin absorber, like those used by the mentioned products will have no real benefit either. Polyfill or fiberglass stuffing the enclosure is meant to increase the effective volume of the enclosure. 

I've read through the Focal sound deadening products site and the marketing to fact ratio is disturbingly high. I've never seen them in person, I expect the quality to be good, but the claims made aren't worthy of a respected brand.


----------



## Matthew Borgardt (Aug 13, 2016)

Sorry, I thought that was obvious... also remember wood glue is necessary between the joint locations. This will ensure no other unwarranted resonance will happen.

Matt Borgardt


----------



## QualitySound (Oct 27, 2015)

Matthew Borgardt said:


> Sorry, I thought that was obvious... also remember wood glue is necessary between the joint locations. This will ensure no other unwarranted resonance will happen.
> 
> Matt Borgardt


Thanks, and it is obvious, I guess, so it's me not you. I have a lot to learn so I can work my way up to the obvious. Looking forward to getting there!


----------



## Matthew Borgardt (Aug 13, 2016)

QualitySound said:


> Thanks, and it is obvious, I guess, so it's me not you. I have a lot to learn so I can work my way up to the obvious. Looking forward to getting there!


 

Matt Borgardt
Oncore/Cadence/Logic


----------

