[konut]

I took the opportunity, when doing some repair to my home, to have Homasote installed on the front exterior, under the siding, as its relatively close to the road. I find myself with an extra 4X8 sheet of Homasote. I also have some OC 703. Here are my questions.

1. Is it worthwhile to use the Homasote with the construction of bass traps?
2. I know that corners are the best place to place the traps. Should I build them in a rectangle, or would a triangular shape be more effective?
3. Should the trap have only 1 side of Homasote, 2 sides, etc.?
4. What would be the optimal dimensions, being able to utilizes the entire sheet?
5. I will be able to standoff the traps from the wall. Is there an optimal distance?

My carpenter is an audiophile and is willing to built the frames to encase the Homasote and 703. I'll house the whole thing in an acoustically transparent fabric. My room listening room dimensions are 10 X 14 X 7'6". TIA for any advice.

[bpape]

Homasote is more meant for blocking sound from getting into a home and really doesn't have much acoustical value in terms of absorption. 

Corners are an efficient place for bass absorption but not the only place where they can be of benefit. 

From a 4x8 sheet, you'd get 4 2x4 pieces.  Probably the best thing would be to make 2 4" thick panels from it straddling the corner. 

When straddling a corner, you have the air gap built in already.  If you're going to use them flat on a wall, make the gap the same as the thickness of the absorbing material.

Bryan

[Ethan Winer]

Bryan must be thinking of a different material. Homasote is a very good absorber, and it's similar to the stuff office ceiling tiles are made from only better. It makes a fine outer wrapping for bass traps filled with 703 or fluffy insulation.

A rectangle is better because it has twice the volume of a triangle, but it sticks out more into the room. For a rectangle you'll use two pieces, for a triangle only one. The walls comprise the other two sides. Corner traps like this should be tight into the corner, with no gap. A front face of 24 inches is good, and 36 inches is even better.

--Ethan

[bpape]

It may be something different.  The Homasote I've seen usually is around 25-30 pcf and pretty rigid to be used in this type of application. More normally used for house sheathing, insulation, and sound abatement applications.  If what you have is something more like the composite ceiling tiles which are more like compressed recycled paper of a much lighter density, then yes, it could work OK.

Bryan

[Bob in St. Louis]

"Homasote" is the name of a company that has several products made under their own individual names. So you fellas all may be correct, just talking about different Homasote products:
http://www.homasote.com/products/

Hope that helps.
Bob

[konut]

Thank you, gentlemen. All good info. The product I have is NovaCork.
http://www.homasote.com/products/NovaCork.aspx
Specs.
http://www.homasote.com/3Part/NovaCork_3PartSpecifications.pdf

[Ethan Winer]

The product I have is NovaCork.

Ah, that's different. Regular Homasote is made from ground up paper pulp, so it's effective as an absorber and won't block bass from passing through.

--Ethan

[konut]

NovaCork is the regular Homasote with a thin veneer of cork. Will the cork block the low frequencies?

[Red Dragon Audio]

NovaCork Density:  24-28 lb./ft.³

That's just too dense to be used as an acoustic absorber.  Just use the 703 and fabric for your panels.   

[tasar]

Hi Konut....still using Bob's waveguides? Great speakers. I just wanted to add the Ecocell batt is not discussed much, comes in every imaginable thickness and rigid enough to have a minimal faceframe attached at rear to hang and provide gap. For true bass only, a face layer of Kraft flooring paper applied w contact spray works really well and super light..... The face or picture frame rear makes for an attach point for fabric and lightweight alternatives to wood, eg foam strips, balsa, etc, give just enough rigidity,,, think "kite" - like

[tasar]

Just to add to the above..... Thermafiber's SAFB is a superior knockoff of Roxul at half the price.... Sourced at Home Acres here in Midwest

[konut]

Hi tasar, and thanks for the suggestions. Still digging the TP Minis! House is still undergoing refurbishing. Bass traps on hold for now.