[jlafrenz]

I am looking to build some bass traps for a room with 10ft tall ceilings. I have made several panels before including bass traps typically using Roxul60 2"x2'x4' panels and double stacking them. For the room I am working on, I am thinking about making a basic frame in the corner forming a triangle and using some sort of mesh to cover the front of it to hold in some loose material. This would allow me to build a taller panel and hopefully same some money by using a different material. My question is what material would be best suited for this? Would some sort of fiberglass found at the local hardware store be sufficient or would I need to look for other materials?

[jk@home]

Here you go:

http://forum.studiotips.com/viewtopic.php?t=535

I'm doing a hybrid of sorts, built custom 2' x 7' x 6" frames (due to roof cut-in on ceiling), place diagonally into the corners, and will have 24" x 17" x 17" triangles behind them. Using Owens Corning 703 insulation panels.

These folks sell the OC703, maybe there's a branch near you:

http://www.distributionintl.com/locations.html

[Big Red Machine]

I have almost three boxes of 703 at two inches thick of 18 x18 x 24 triangles for two corner traps if interested in precut pieces.

[jlafrenz]

Here you go:

http://forum.studiotips.com/viewtopic.php?t=535

I'm doing a hybrid of sorts, built custom 2' x 7' x 6" frames (due to roof cut-in on ceiling), place diagonally into the corners, and will have 24" x 17" x 17" triangles behind them. Using Owens Corning 703 insulation panels.

These folks sell the OC703, maybe there's a branch near you:

http://www.distributionintl.com/locations.html

This is similar to what I want to do, but my goal is to avoid using rigid fiber board for a couple of reasons. The first is the height of the ceiling. I don't know how well 3 sheets would stack. The second is the amount of them an work it would take to cut them into wedges to fill the corner. I figure that a loose material that could be stuffed into a frame would be easier, take less time and be cheaper.

[jk@home]

They mention a few other alternatives on that web page.  I've found using a large kitchen "chef's" knife works great cutting that type of stuff.

[jlafrenz]

They mention a few other alternatives on that web page.  I've found using a large kitchen "chef's" knife works great cutting that type of stuff.

I typically use a bread knife to cut rigid fiber board. Works really well.

[mikeeastman]

I used a product called Ultra Touch, it's made from recycled blue jeans, is nicer to work with than fiberglass and slightly better than fiberglass at sound absorption. Home depot carries it and it comes in batts and loose fill.

[jlafrenz]

I have been doing some research since first posting this and it seems that R-13 pink fiberglass works well for "superchunk" style bass traps. I have seen a few mention Roxul Safe and Sound as another option. Just curious how these compare for the "superchunk" bass traps?

[Big Red Machine]

I typically use a bread knife to cut rigid fiber board. Works really well.

For 703 I use a table saw.  Hard to cut straight with a carving knife.

[Big Red Machine]

I have been doing some research since first posting this and it seems that R-13 pink fiberglass works well for "superchunk" style bass traps. I have seen a few mention Roxul Safe and Sound as another option. Just curious how these compare for the "superchunk" bass traps?

Pink R13 would be a waste of time in my book.  You need the pound cake of insulation and that is 703 or 705 or Roxul equivalent to stop multiple frequencies.  I think Bob Gold or someone had a website that listed the absorption characteristics of materials and standard pink insulation is only good for very high frequencies unless you could compress multiple layers of it to replicate the density of 703.  Not a practical task. 

A box of 703 shipped these days is in the $75 area for 12 inches thick, 2 feet wide, by 4 feet long in thicknesses of 1, 2, 4, or 6 inches.  Two boxes cut into triangles will give you 2 corner traps for 8 foot ceilings.

[SteveRB]

I used a product called Ultra Touch, it's made from recycled blue jeans, is nicer to work with than fiberglass and slightly better than fiberglass at sound absorption. Home depot carries it and it comes in batts and loose fill.

This stuff is great -- And easy on the lungs.

[jlafrenz]

Pink R13 would be a waste of time in my book.  You need the pound cake of insulation and that is 703 or 705 or Roxul equivalent to stop multiple frequencies.  I think Bob Gold or someone had a website that listed the absorption characteristics of materials and standard pink insulation is only good for very high frequencies unless you could compress multiple layers of it to replicate the density of 703.  Not a practical task. 

A box of 703 shipped these days is in the $75 area for 12 inches thick, 2 feet wide, by 4 feet long in thicknesses of 1, 2, 4, or 6 inches.  Two boxes cut into triangles will give you 2 corner traps for 8 foot ceilings.

Interesting. I have been reading several threads that say R-13 is adequate and may even be better for bass traps. This is based off of the "superchunk" design, not rigid panels spanning the corners. I welcome further discussion about these 2 materials. 

[kwarny]

Interesting. I have been reading several threads that say R-13 is adequate and may even be better for bass traps. This is based off of the "superchunk" design, not rigid panels spanning the corners. I welcome further discussion about these 2 materials.

There is an inverse relationship with gas flow resistance (GRF) and thickness of a trap.  As the trap becomes thicker, a lower GFR material (pink fluffy) will absorb down lower.  Compressing the fluffy will decrease low end performance.

http://www.acousticmodelling.com/

GFR of 703 is around 16000
GFR of Pink Fluffy 5000

[jlafrenz]

There is an inverse relationship with gas flow resistance (GRF) and thickness of a trap.  As the trap becomes thicker, a lower GFR material (pink fluffy) will absorb down lower.  Compressing the fluffy will decrease low end performance.

http://www.acousticmodelling.com/

GFR of 703 is around 16000
GFR of Pink Fluffy 5000

Your comments are more in line with what I had been reading. What I couldn't find is if there is a specific depth that the bass trap needs to be. Most unfaced R-13 is 15" so my plan would be to cut a 15x15 square in half on the angle which would result in roughly a 21.2" wide bass trap in the front facing into the room. This would make the depth of the trap roughly 10.6". Would this be sufficient depth for R-13 to work effectively?

[Glenn Kuras]

Your comments are more in line with what I had been reading. What I couldn't find is if there is a specific depth that the bass trap needs to be. Most unfaced R-13 is 15" so my plan would be to cut a 15x15 square in half on the angle which would result in roughly a 21.2" wide bass trap in the front facing into the room. This would make the depth of the trap roughly 10.6". Would this be sufficient depth for R-13 to work effectively?

You are going to want them thicker and wider then that. I would look to make them 24" across the corner and 17" on the sides.

Glenn
GIK Acoustics.

[jlafrenz]

You are going to want them thicker and wider then that. I would look to make them 24" across the corner and 17" on the sides.

Glenn
GIK Acoustics.

Thanks for your response Glenn. At a 24" face, will R-13 be sufficient as a bass trap or would I be better of going with Roxul Safe and Sound?

[jk@home]

There is an inverse relationship with gas flow resistance (GRF) and thickness of a trap.  As the trap becomes thicker, a lower GFR material (pink fluffy) will absorb down lower.  Compressing the fluffy will decrease low end performance.

http://www.acousticmodelling.com/

GFR of 703 is around 16000
GFR of Pink Fluffy 5000

That's interesting. Presently I have some 25-1/2" x 81" x 6 " thick panels of OC703 placed diagonally in my corners and have thought of also throwing some 17x17x24 triangles behind them as additional trapping. If I used loose pink fluffy (or the equivalent) behind the panels, instead of more OC703, would I get better low frequency trapping performance? I'm using IB subs in the room.

[Glenn Kuras]

Thanks for your response Glenn. At a 24" face, will R-13 be sufficient as a bass trap or would I be better of going with Roxul Safe and Sound?

I personally have not test either of those but if the trap is filled corner, meaning it is large and thick R-13 will work well.

[Big Red Machine]

This is where my memory was working from:

http://www.bobgolds.com/AbsorptionCoefficients.htm

6 inches of std 703 is twice as effective at 125 hz that 6 inches of pink OC

What is it that makes a super chunk effective?  Not sure I understand.

My corner traps were as Glenn pointed out, 24 inches across the face which made them almost 12 inches deep at the triangle height.

[bpape]

It has to do with density of the material.