Does using Blackhole 5 (or similar) affect enclosure? volume (4 Viewers)

[Patrick Sun]

Some people use that Blackhole 5 stuff to dampen their speaker enclosures. I was wondering if it had any effect on the effective enclosure volume, or do you treat it like there was no Blackhole 5 installed at all?

 

[jeff lam]

On Dennis Murphy's MB1 site he said to line the walls of the enclosure but do not stuff the middle of the enclosure because it will change the tuning frequency. I guess he's saying that stuffing an enclosure will indeed effect the volume but lining the walls won't. I'm no expert though so don't take my word for it.

 

[Brian Bunge]

Pat,
I believe the Black Hole 5 is mostly an open cell foam type material so I don't think it should have much affect on the volume of your enclosure. I've had a few sheets but haven't used it in any speakers I've built for myself yet. I'll use it in my A/V-1+'s after I finish veneering them. And might even use it in the Adire LCC center channel I won.
Also, my dad bought a bunch of sheets of the 4 layer damping material that Parts Express is selling. It's definitely not the same as the Black Hole 5, but is similar and much cheaper. We can sell you a sheet if you want to try it.
Brian

 

[Patrick Sun]

It was a random thought that popped into my head because of the implications if the stuff did make a difference in either adding to or subtracting from the overall enclosure volume (even when lined on the walls). I will pass on the offer on the 4-ply stuff (not really in an experimental mood currently), but thanks for the offer.

 

[Brian Bunge]

Pat,

Random thoughts, huh? Daydreaming in the middle of the week sounds more like it!

Brian

 

[Anthony_Gomez]

From what I read a while ago, the blackhole occupied 1/4" of effective displacement.

 

[JerryD]

I purchased a sheet of the "4-layer damping material" from PE with the intention of using it in a pair A/V-1+s that I am to be building soon. Does anyone have any info on how it compares to the real Black Hole 5 material, or have you used it in A/V-1+s?

 

[Rob Lloyd]

I'm about to build the Av1+'s (tonight if nothing comes up). Danny R said that if you use BH5 in them you don't need the diagonal braces. Has anyone tried it that way or done a comparison w/ or w/o the extra braces?
He said you don't need the stuffing then either? But some/most of you are using both.

Any suggestions on what to do?

Thanks,
Rob

 

[Brian Bunge]

Rob,

We are building cabinets for Danny and will be building the A/V-1+'s without the diagonal braces. I've got a pair at the shop just waiting for cherry veneer (but have other cabinets that are taking priority at the moment) and I didn't use the braces. I think as narrow as the cabinets are, they should be fine without the diagonal braces. As heavy as the BH5 is (8 lbs. per sheet), I'd think it would damp out any resonances pretty well.

Brian

P.S. Did Martice get you to paint his A/V-1+'s?

 

[Rob Lloyd]

Thanks. Those braces looked like a pain to do anyway! What about stuffing? Yes or no?

RE: Martice's AV1+s - Not yet. He wants a glossy piano black finish on them. I'm going to do mine 1st for practice and to make sure it passes his quality approval. Plus he's getting a ride to CT from someone w/ them so we don't have to deal w/ shipping them.

I mentioned black to my wife and she tought it was kind of boring, so I may do another color instead now. Or veneer them and paint my upcoming 281's and LCC piano black.

Do you completly cover the sides, back, top and bottom w/ BH5?

Thanks,
Rob

 

[Brian Bunge]

When I built Martice's, I covered the sides of the three chambers created by the shelf braces, the top and the back wall behind the top driver. His cabinets did have the diagonal braces so they took up some room. I didn't put any on the bottom since part of the crossover is mounted there. He did add stuffing behind the two woofers but left the area behind the tweeter open. He said it improved the sound quite a bit, IIRC.

Concerning cabinet finish, I'm veneering mine with cherry and then staining them with red mahogany dye. I've finished some Paradox 1's the same way and they look awesome! I've got pics I can email you if you'd like to see them.

I just won a LCC kit from HTT, so I'll be building that soon too! I'll try it out with the A/V-1+'s and see how well they blend. I'd really like to find someone local to me with the 281's so I could compare them to the A/V-1+'s. I know the 281's will beat them for bass response, but I'm looking for midrange clarity. If the LCC doesn't blend well with the A/V-1+'s I'll have to decide whether to keep it and switch to either 81's or 281's or just go with 3 A/V-1+'s.

Brian

 

[Hank Frankenberg]

Patrick, when Danny R brought the drivers for the Alpha LS cabinets I built for him, he brought a BUNCH of BH5 material and lined most of the internal walls with it. I asked him about its effects on volume. He said to ignore it and assume it does not detract from internal cabinet volume.
Personally, I've been using Parts Express' #268-020 asphalt-based dampening sheet material: http://www.partsexpress.com/pe/showd..._ID=7083&DID=7
They've got a new vinyl dampening sheet #268-035 they advertise as "twice the damping and half the wieght, so I ordered a roll of it and will try it soon: http://www.partsexpress.com/pe/showd...ID=15840&DID=7
I know this thin stuff is not in the same league as BH5, but the cost of BH5 makes its use rational only in very top-end applications.
Rob, good zinger, I'm also tired of Brian's gloating. I never win anything.

 

[Rob Lloyd]

I know you won the LCC, you're posting that everywhere. Stop gloating already!
I'll add it on those places and add a little stuffing behind each woofer. How much do you think? I know the 281s are pretty well packed.
The finishing problem is we're going to be moving and we don't know what we're going to end up with. Sure send me some pics. I've got a few different species of raw veneer I might play with on them.
I'm looking forward to being one of the 1st to compare the 281s and the AVs. Should be interesting.
Rob

 

[Brian Bunge]

Hank,
Half the weight but a higher price? What a ripoff!
Rob,
Sorry, can't help but gloat! I never win anything! Almost didn't even enter for that very reason!
I'm not sure how much polyfil to use. IIRC, Martice said he used a little over a 1 lb. bag of polyfil to do all three of his enclosures, but double check with him to be sure.
I'll send the pics.
Brian

 

[Kevin Deacon]

Has anyone thought of using roofing felt for damping. It's cheap and available at HD or Lowe's. I have lined my AV1's with 3 layers of 30# roofing felt, which comes to about 1/4"(5mm)thick. I will then use some 2" poly batting to line all sides except the baffle. I am still in the varnish phase with these so I won't know how they react until early next week.
I did get to listen to my set of Proac Response 2.5 clones this last weekend for about 2 hours before one of the woofers died. These cabinets are floor standers with minimal bracing. I lined these also with 3 layers of 30# roofing felt. While listening at high volumes the cabinets had very minimal vibration. I believe the original production Proacs ($4,500) are lined with the same material.
Just a suggestion

 

[Joe Meissner]

I used car undercoat spray in my subwoofer and couldnt believe how much it deadened the enclosure. it was cheap and easy. just a little messy though

 

[Greg Monfort]

>Has anyone thought of using roofing felt for damping.
====
Uh, yeah. I first read about it back in the '50s and have used/recommended it on many occasions over the decades. Good for damping between layers of plywood too. It has fallen out of favor with the advent of all the variants of foam though.
GM