cotton absorbers

[tommyboy]

I am just wondering if there's anyone out there besides me that uses Bonded Logic's recycled blue jean cotton for sound absorption. I used this in the construction of my studio walls but after seeing the absorption coefficient on bobgolds.com, I had to try it later on the walls. I don't have measurements but it has quieted my room down. Just to be safe I typically hang up a batt outside before installing and beat it with a tennis racket until most of the powdered treatment is gone. It's a pure guess on my part but I think it would be safer (air quality-wise) than rock wool or fiberglass... and if the numbers below are accurate then it's phenomenal. I plan to use more in the future for corner traps. I'm just surprised that I don't hear more about it being used.

 

[Sonnie Parker]

I wonder how those number compare to the same thickness of Rockwool.

 

[NBPK402]

I used Blue jean insulation (got it at Lowes) in my old HT for my soffits...seemed ok.

 

[NBPK402]

I wonder how those number compare to the same thickness of Rockwool.

It is not compressed like Roxul is, but is more dense appearing than fiberglass insulation (if it is the same Blue Jean Insulation I got from Lowes)...IMO.

 

[tommyboy]

I wonder how those number compare to the same thickness of Rockwool.

looks like Rockwool is right up there!

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

 

[NBPK402]

View attachment 47426
looks like Rockwool is right up there!

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

I was running REW for tuning my speakers...with the panels on each side of my speaker and one on the floor (all 2" R60, and then tried it again with 2 layers of R60 but this time made them in the shape of a 4' 4' wall in front of the speaker...man did it change the reading! I had deep nulls and peaks where there was none before. I then went and used the 2 layer Roxul on each side of my speaker and noticed the only dip...was a couple of db lower from around 500hz and up. It def works!

 

[hemiutut]

I was running REW for tuning my speakers...with the panels on each side of my speaker and one on the floor (all 2" R60, and then tried it again with 2 layers of R60 but this time made them in the shape of a 4' 4' wall in front of the speaker...man did it change the reading! I had deep nulls and peaks where there was none before. I then went and used the 2 layer Roxul on each side of my speaker and noticed the only dip...was a couple of db lower from around 500hz and up. It def works!

Hello
Does this room have measurements made with Room Eq Wizard for example?
Just curious to see the acoustics of it.

Written with translator.

Greetings

 

[NBPK402]

I posted them up in the REW thread as I could not understand the huge differences.

 

[Cary B. Cornett]

I am just wondering if there's anyone out there besides me that uses Bonded Logic's recycled blue jean cotton for sound absorption. I used this in the construction of my studio walls but after seeing the absorption coefficient on bobgolds.com, I had to try it later on the walls. I don't have measurements but it has quieted my room down. Just to be safe I typically hang up a batt outside before installing and beat it with a tennis racket until most of the powdered treatment is gone. It's a pure guess on my part but I think it would be safer (air quality-wise) than rock wool or fiberglass... and if the numbers below are accurate then it's phenomenal. I plan to use more in the future for corner traps. I'm just surprised that I don't hear more about it being used.

View attachment 47423

Your best and most cost effective choice for broadband absorption (bass trapping is different) is standard fiberglass roll unfaced wall insulation, the deeper the better. Not less than 6 inches thickness, and thicker is better. My preference is that attic blanket stuff. What you do is wrap a wood frame around the edges of the stuff. You cover the faces of the fiberglass with quarter inch poly quilt batting (do NOT use cotton), and burlap makes a good front covering. On the back you could use something less pretty like window screening. These frames can then be mounted to walls and ceiling. Note that these will not fix low frequency response, just kill reflections for the mids and highs. If you build these as I have described, you don't need to worry about loose fibers getting out or any outgassing. I have a set of similar frames I made 20 years ago and still use them. By comparison, the fabric you describe is too dense, as are any fiberglass or rockwool products that form rigid panels. Likewise avoid acoustical foams unless they are at least 6 inches thick, and be aware that the foam costs more than equivalent coverage fiberglass.

 

[tesseract]

I've seen floor-to-ceiling corner traps made of recycled blue jeans cotton. The guy is a stickler for measurements, so I imagine he found the material worthy.

 

[DanDan]

Recycled cotton fibre has excellent absorption in relatively thin or shallow traps. I have read, and believe, that it has a higher Gas Flow Resistivity than other fibres. So beyond say 6" deep trapping, the wavefront will have a hard time getting in. LF waves will in fact get reflected. My friend and great Acoustician Boggy, sadly RIP, designed fully Pro Control Rooms etc. using light Earthwool or other fibres. 2' deep all boundaries. Perfect response to EBU specs. BBC worked with about 1' depth using combinations of modules. Some with membrane facing, in reality, hardboard!