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Speaker Cabinet Insulation

#41
I see this is an old post and I might not get a reply by asking it - but I want to know a few things about placement of the sound-deadener material.

There are corners in every box (well, maybe not all) and I wonder what the tri-corners and 90º wall intersections do to the sound waves in a few different sound arenas.

Can we talk separately about the following?
1) The HIGH freqs
2) The MID freqs
3) The LOW freqs.​
Is it better to at least curve or run the insulation into those angles and corners or can they just be left exposed.

Is it more important to cover all the flat surfaces inside the box?

Thicker insulation on the rear wall or the area directly adipose to the speaker mounting area?

What about gaps from the factory in the material? Are these places that generate and/or create parasitic and possibly dissonant freqs?

Do these gaps themselves steal power (perceived or otherwise) from the audio output out the front of the cab?

Should the material be closely stapled or rather 'loosely' to the box interior?

Sorry for dredging up an old post, but I don't see answers to these questions - if they are even important.
 
#45
terror08 said:
The material of from those who build cab's is pink insulation. You know, also known as rock wool, house insulation. Stuff you get from build material stores...
Click to expand...

Surely millions of cabs out there are lined with pink or yellow fiberglass insulation, but since better materials are as easy to come by I'd steer away from the fiberglass.

IE) I just opened up an old ACME that was nicely lined on all interior surfaces with fiberglass. A fine fiberglass dust came out when removing one driver. The more you move the stuff, the more its fibers break free. I;ve installed plenty attic insulation in my day, but the itchy factor from the old cab was on par with a full attic install. Maybe all those cones moving and port air bumping causes them to break up more? I dont know, but its one mess thats just not necessary imo.

Just use the fiber-fill from an old cheep pillow, or some old matress topper, or the like. Walmart, craigslist, etc. If you are really cheep, you can get miles of the stuff in college dorms at the end of the year, or even use an old flannel shirt or fleece blanket tripled over and stapled.

incidentally, the Acme was the most carefully lined commercial cab I have looked in. every bare wall was lined with a couple inches. For example the Carvin lsx had one wall lined, ampeg had peices of 3 or 4 walls lined, or the Schroeder which had no cab lining.
 
#47
rcgtrix said:
If a cabinet is optimally sized for a driver's parameters, will stuffing...alter the performance of the speaker?
Click to expand...
No. Stuffing is only useful when the cab is too small for the driver, which results in a high Q and therefore boomy response. A properly sized cab need only be lined.
 
#49
You'll also want to reduce internal temperature. Foam products will accomplish suppression of the standing waves if they have acoustical absorption properties, but they will not have the thermal properties like the fiberglass. This is why foam is not recommended.
 
#50
Echodrive said:
You'll also want to reduce internal temperature. Foam products will accomplish suppression of the standing waves if they have acoustical absorption properties, but they will not have the thermal properties like the fiberglass. This is why foam is not recommended.
Click to expand...
This is not true.
 
#51
I just got a pair of vintage book shelf speakers, and thought they could use more insulation. Luckily I had something ready to use. A few weeks ago I picked up a piece of "Fairfield Nu-Foam". It's a square of polyester designed for cushions. It's 2 inches thick and can stand on its own if it's pressing against the sides of the box, so I don't think I need glue to keep it in place. The square was the perfect size to insulate the back of the two boxes.
 
#52
Whatever you're sourcing as foam, make sure it's "open cell" foam, meaning you can easily blow through it, like an air filter. Closed cell foam will shrink the box.

And +1 to fabric stores. Great places to get cool, out of the norm covering ideas.....so many in fact it can be darn hard to decide on one.
 
#53
Whatever you're sourcing as foam, make sure it's "open cell" foam, meaning you can easily blow through it, like an air filter. Closed cell foam will shrink the box.
Click to expand...

This makes sense. I picked up 2" thick poly open cell foam from Hobby Lobby for my last project - a 4.3 ft3 cab loaded with a pair of Eminence 3012LF woofers. It cuts like a loaf of bread with an electric carving knife and stays firmly in place with a shot of 3-M spray adhesive. 1" just didn't seem enough for that large high power cab and they didn't have 1.5" so I just went with 2". Not sure if it borders on overdamped but it sounds excellent so I'm going to leave well enough alone.
 
#55
Tighelander said:
I just got a pair of vintage book shelf speakers, and thought they could use more insulation. Luckily I had something ready to use. A few weeks ago I picked up a piece of "Fairfield Nu-Foam". It's a square of polyester designed for cushions. It's 2 inches thick and can stand on its own if it's pressing against the sides of the box, so I don't think I need glue to keep it in place. The square was the perfect size to insulate the back of the two boxes.
Click to expand...

+a million.. The local fabric shop carries "Nu-Foam" under the poly-fil brand. Comes in 1" and 2" thicknesses, and its the perfect stuff for lining cabs.. A bit pricey, but i believe its worth it for my fEARful builds..
 

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