What do you guys use to line your enclosures?

[scott_s]

I know this has been discussed before, but I am in the middle of my Schumakubin build and I need suggestions for lining material for a vented box. People have mentioned carpet padding, fiberglass, and even concrete backer board with roofing felt. Right now I'm leaning towards carpet padding but I'm open to suggestions. I'm sure one of the Blackhole-type products would be great, but I'm trying to keep this on a budget (somewhat). I have three 2.6 cu. ft. boxes to line, so I'm looking for best bang for the buck. Ease of application is also a big plus. Opinions? Thanks.
Scott S.

[shawn_a]

I'm a big fan of stuff that'll kill ya so I generally use fiberglass to line my enclosures. Get the small job rolls of unbacked 'glass at most any hardware store or big box home store. I've bought the Frost King stuff and the Owens Corning stuff for about the same price (five or six bucks) and same size (a couple inches thick, 16" wide and 48" long) at Lowe's for a couple of years now.

Gotta go find a gas leak now. Too bad the light in the attic burnt out so I gotta use a candle I guess. After that I have plans to smoke some cigars while laying down some contact cement. ;)

shawn

[AJ]

> Gotta go find a gas leak now. Too bad the
> light in the attic burnt out so I gotta use
> a candle I guess. After that I have plans to
> smoke some cigars while laying down some
> contact cement. ;)

> shawn

Hey Shawn, do you still have your eyebrows?

[mikebw]

Real men don't need eyebrows.

> Hey Shawn, do you still have your eyebrows?

[bill]

Or you can search for the cat under the bed using your cigarette lighter to see with. Some bozo did that around here a couple of weeks ago; he burned down his house. The family made it out; the cat didn't, unfortunately.

Best regards,
Bill

> I'm a big fan of stuff that'll kill ya so I
> generally use fiberglass to line my
> enclosures. Get the small job rolls of
> unbacked 'glass at most any hardware store
> or big box home store. I've bought the Frost
> King stuff and the Owens Corning stuff for
> about the same price (five or six bucks) and
> same size (a couple inches thick, 16"
> wide and 48" long) at Lowe's for a
> couple of years now.

> Gotta go find a gas leak now. Too bad the
> light in the attic burnt out so I gotta use
> a candle I guess. After that I have plans to
> smoke some cigars while laying down some
> contact cement. ;)

> shawn

[shawn_a]

> Or you can search for the cat under the bed
> using your cigarette lighter to see with.
> Some bozo did that around here a couple of
> weeks ago; he burned down his house. The
> family made it out; the cat didn't,
> unfortunately.

> Best regards,
> Bill

Yep, house fires usually start in the most careless of ways. A family in a neighboring town burnt the place down to the slab a couple of weeks ago. Turns out they had their oven set to self clean mode and forgot about it. Next thing ya know, whoosh. Call the insurance company honey.

shawn

[dancarroll]

Vented? 3/4" mdf? Decently braced? You don't need any of that other stuff. Egg crate foam. PE's is very nice and what I would use if using good drivers. For budget projects, I used a WalMart egg crate foam mattress pad.

[Wolf]

http://i18.photobucket.com/albums/b117/wolf_teeth_speaker/Marianas/subM021.jpg


It's sport-flooring for about $11- 23" x 23" 3/8" thick. It's heavy, and fairly dense. You can either use a good adhesive(I used the E6000 from Walmart), or just screw it to the inside. =-) I did that in the "Marianas" subwoofer project. It was used in combination with poly-fil batts or stuffing, or eggcrate foam. It's been a good combination. You don't have to cover the whole panel with it, just pieces where resonances could be possible. I mass-loaded 5 pieces (about 1.5" square) in the "Sir Audinum" project, because the Oak was less dense than the mdf is typically, and then I placed egg stuff behind the midbasses, and poly-fil stuffing for the remainder. These are only 11" x 5.5" x 5.5", so the 'flooring' additive was minimal. It works well! And it's fairly cheap!
Later,
Wolf

"Sir Audinums":
<A HREF="http://i18.photobucket.com/albums/b117/wolf_teeth_speaker/100_2512.jpg">http://i18.photobucket.com/albums/b117/wolf_teeth_speaker/100_2512.jpg</A>
"Marianas" with batts:
<A HREF="http://i18.photobucket.com/albums/b117/wolf_teeth_speaker/Marianas/subM022.jpg">http://i18.photobucket.com/albums/b117/wolf_teeth_speaker/Marianas/subM022.jpg</A>

[gc1]

This happens to be one of the things that interested me the most in my building "start-up" stage. Did alot of experimenting, and like this idea I'm planning for my next pair. I'm going to apply and let dry; a coat of solvent-free vinyl tile adhesive... then mix this same adhesive with cellulose/recycled paper blow-in insulation, and apply to dry/tacky surface/s (one wall at a time). When dry, then add the usual polyester stuffing to remaining interior space.

GC

> I know this has been discussed before, but I
> am in the middle of my Schumakubin build and
> I need suggestions for lining material for a
> vented box. People have mentioned carpet
> padding, fiberglass, and even concrete
> backer board with roofing felt. Right now
> I'm leaning towards carpet padding but I'm
> open to suggestions. I'm sure one of the
> Blackhole-type products would be great, but
> I'm trying to keep this on a budget
> (somewhat). I have three 2.6 cu. ft. boxes
> to line, so I'm looking for best bang for
> the buck. Ease of application is also a big
> plus. Opinions? Thanks.
> Scott S.

[jim85iroc]

I use the premium 1/2" carpet padding from Home Depot. I built a pair of small 2 ways a couple years ago, and tested a few different materials, including that carpet padding and some various foams that I got from Jo-Ann Fabric. The differences between the foams were completely inaudable. Some of these foams, while not in the shape of an egg crate, were the same density. The carpet padding made a clearly audible difference. Midrange was drier, more clear.

Recently I built a pair of Zaph's Silver Flute Vifa 2-ways and the difference with and without the padding was remarkable. Without it, vocals were unpleasant and resonant, but with 2 layers of the carpet padding, they were liquid smooth with tremendous detail. I have yet to try a premium product like whispermat, but for budget oriented designs, I'm a firm believer in 2 layers of carpet padding.

> I know this has been discussed before, but I
> am in the middle of my Schumakubin build and
> I need suggestions for lining material for a
> vented box. People have mentioned carpet
> padding, fiberglass, and even concrete
> backer board with roofing felt. Right now
> I'm leaning towards carpet padding but I'm
> open to suggestions. I'm sure one of the
> Blackhole-type products would be great, but
> I'm trying to keep this on a budget
> (somewhat). I have three 2.6 cu. ft. boxes
> to line, so I'm looking for best bang for
> the buck. Ease of application is also a big
> plus. Opinions? Thanks.
> Scott S.

[scott_s]

I appreciate everyone's input. I had almost forgotten about the egg crate foam like Dan mentioned. But it seems to me that since the carpet pad is so much more dense than the egg crate foam that it might deaden the cabinet better. I think that sport flooring that Wolf uses would be similar to the carpet padding also. I used fiberglass exclusively in my early days and was never completely satisfied with the results, but my boxes weren't nearly as well-braced as they are now either. That probably had more affect on the sound than the fiberglass did. Thanks.
Scott S.

[curt_c]

To dampen the enclosure wall resonances, you want to use something fairly dense, such as the carpet padding, layers of roofing felt, etc. The energy striking the material is partially absorbed by moving the mass of the material and turning to heat. The key here is most all of this material will be of non-porous construction, and will reduce the enclosure volume.

To dampen the internal waves you want to use a porous, or open cell type of product, such as acoustic foam, fiberglass, etc. This does little to dampen the walls, but attempts to diminish the acoustic energy of the waves inside the enclosure, and keep it from interfering with the driver cone movement.

Building a well braced enclosure, which moves the resonant frequency above the pass band of the driver is always a good solution. It cannot resonate if its resonant frequencies are not excited. Constrained layer construction, where there are at least two layers separated by a viscoelastic layer is another possibility. This could be as simple as two layers of MDF glued together with a product such as found here:

<A HREF="http://www.quietsolution.com/html/quietglue.html">http://www.quietsolution.com/html/quietglue.html</A>

BTW, I haven’t used this product, but it looks promising. $60/gallon, though…

These type of enclosures should require little, if any, additional damping,

Products like Sonic Barrier attempt to address both issues in one appliance. How well, I can’t say, as I’ve never used them. I have used Deflex panels, and they seem to clean things up a bit…
.
C

[scott_s]

Curt,
I agree with your theory completely - there is a difference between dampening enclosure resonances and dampening internal waves. But you include carpet padding in the "enclosure resonance" category and not the "internal wave" category. This is where I'm not sure I completely agree. Carpet padding is porous, isn't it? It will cerntainly absorb liquid (my daughter has confirmed this many times :)

You have surely forgotten more about speaker building than I will ever know, so I'm not trying to argue with you. I just want to understand. So what do you use for "internal wave" damping in your enclosures?

I looked into the constrained layer construction but in the end I felt it was overkill (read: more work than I was willing to do) for this project. I think it is a great idea for ultra high-end projects though.

Thanks for your input.
Scott S.

[dancarroll]

> To dampen the enclosure wall resonances, you
> want to use something fairly dense, such as
> the carpet padding, layers of roofing felt,
> etc. The energy striking the material is
> partially absorbed by moving the mass of the
> material and turning to heat. The key here
> is most all of this material will be of
> non-porous construction, and will reduce the
> enclosure volume.

> To dampen the internal waves you want to use
> a porous, or open cell type of product, such
> as acoustic foam, fiberglass, etc. This does
> little to dampen the walls, but attempts to
> diminish the acoustic energy of the waves
> inside the enclosure, and keep it from
> interfering with the driver cone movement.

> Building a well braced enclosure, which
> moves the resonant frequency above the pass
> band of the driver is always a good
> solution. It cannot resonate if its resonant
> frequencies are not excited.

Yup, I think that is what I said above, though as always not nearly as well or completely as the founder and Pope of the Church of Curtology!

Dan

[waynew]

Scott,

Carpet Padding isn't really porous in the speaker building sense. If you can breathe easily through it, it can be considered porous. Mind you, there are several types of carpet padding, and some are somewhat porous.
To give you an idea of how I line my cabinets please see my list:
1. Knock test - any ringing in the drivers band
2. Lining the walls with tile if knock test fails
- I rarely have to do this as I tend to brace the snot out of my cabinets and the knock test passes with flying colors
3. Place driver in and listen to check for standing waves.
3a. If standing waves are present, place some Fiberglass/Accousta Stuff/Daycron (your choice) in a loose ball behind the driver, and place some in strategic places in the cabinet (read - spots that will hold the stuffing in place)
3b. Place some egg-crate foam on the walls behind the driver, and on the top and bottom of the enclosure
4. Repeat Knock Test and Driver tests
4a. Add more, or subtract stuffing depending on results of knock test and driver tests
5. Listen to favorite music with look of sublime satisfaction for a job well done.

[curt_c]

> Yup, I think that is what I said above,

Sure, it is.
You didn't think I could come up with this stuff by myself do you?

[dancarroll]

> Sure, it is.
> You didn't think I could come up with this
> stuff by myself do you?

Oh, please! I study at the feet of and bow to the Master!

Dan

[dancarroll]

> 5. Listen to favorite music with look of
> sublime satisfaction for a job well done WHILE DRINKING FINE SCOTCH AND PRAISING YOUR MEMBERSHIP IN THE CHURCH OF CURTOLOGY.

[johnastockman]

[bogie]

If you have a level table, and a little time, dump a bottle of cheap Elmer's in the speak, and let it level itself out...

[curt_c]

> If you have a level table, and a little
> time, dump a bottle of cheap Elmer's in the
> speak, and let it level itself out...

...and season with a generous helping of lead shot before it sets up. ;^)

C

[waynew]

Dan,

Ohhh Boy, I can't believe I forgot that. I hope this doesn't mean that my membership is revoked. I will perform a hundred Hail Curt's and break open a new bottle of Johnny Walker for the required 2 fingers of contrition. Hopefully, that will restore me to good standing!

[dancarroll]

[Pete Schumacher ®]

> ...and season with a generous helping of
> lead shot before it sets up. ;^)

> C

Now that's a pretty neat idea indeed.

[Pete Schumacher ®]

> If you have a level table, and a little
> time, dump a bottle of cheap Elmer's in the
> speak, and let it level itself out...

Not a bad idea Bogie, but Elmers is mostly water.

[curt_c]

> Now that's a pretty neat idea indeed.

But it kills the RoHS compliance...

[bogie]

...with my Savage .22-250, I took a router and a straight bit and hogged out a LOT of the foreend... Then a big drill bit was used on the buttstock. Mix of epoxy and #8 shot, and the rifle, with scope, weighs in at about 18-19 pounds...

[bogie]

Right, but I'll bet the residue will seal the bejeezus outta things...

> Not a bad idea Bogie, but Elmers is mostly
> water.

[porper]

The result will be even more impressive.

[Wolf]

I think that sport flooring
> that Wolf uses would be similar to the
> carpet padding also.

I disagree! It's heavy, and very dense. It looks like ground-up car-tires, that have been formed into sheets. Carpet padding is nothing compared to this stuff, IMO, as it doesn't mass-load as much weight to the panels.
Later,
Wolf

[Wolf]

> Not a bad idea Bogie, but Elmers is mostly
> water.

So use Elmer's Ultimate glue, or Gorilla glue. It'll expand around the shot.
Later,
Wolf