DIY Room Accoustics for Home-Theatre

[sdurani]

Low frequencies by their very nature can unsettle loose objects. Think glass shaking during action scenes.

But the fiberglass is absorbing the bass waves rather than being vibrated by it. Think water drops hitting glass vs hitting sponge.

 

[sash]

But the fiberglass is absorbing the bass waves rather than being vibrated by it. Think water drops hitting glass vs hitting sponge.

By absorption i have always thought that sound energy passes into something and weakens along the way. If the water/air hits the sponge and the sponge was strands of fibers, it would come loose....eventually.....no?

 

[shelley]

Glasswool and Rockwool can and will get powdery as confirmed by experts. The dust which will be coming out will be microscopic and not visible with naked eye. Even suppliers are not recommending using glass wool. Rock wool is slightly better than glass wool in handling and has good acoustical properties.

There are clinical studies about glass wool being carcinogenic in mice..This is the reason why I am concerned despite it being an excellent acoustic material.
Reference:
National Toxicology Program, Department of Health and Human Services, United States

Glass Wool Reasonably anticipated to be a human carcinogen (PDF File)
http://ntp.niehs.nih.gov/ntp/roc/twelfth/profiles/GlassWoolFibers.pdf

Is Fiberglass Safe to Use in Your Home? A Report..
http://articles.mercola.com/sites/articles/archive/2012/04/30/fiberglass-causes-cancer.aspx

Despite the best measures taken to protect it from coming out, there is a possibility of the covering (tissue) deteriorating with passage of time..
Is it worth taking the risk of using glass wool and the possibility of having a life threatening disease like Lung Cancer....?????


NRC values of some materials:
Plywood: 0.10 - 0.15
Wood: 05 - 0.15
Gypsum: 0.6 to 0.75
Polyurethane Foam: (1" thick): 0.30
Fiberglass, 3-1/2": 0.90 - 0.95
Fiberglass, 1" Semi-rigid: 0.50 - 0.75
25 mm thick wood wool : between 0.18 to 0.50 for lower frequencies and 0.72 to 0.80 for higher frequencies..
Polyfibre: 0.7

Wood Wool is not so good at absorbing lower frequencies but good for mid-range and higher frequencies...So for bass traps, polyfibre is an eco friendly material and economical too..

Anutone "Synth PF" 50 mm thick Polyfibre costs:
1000 GSM: Rs.55/- per Sq: ft
500 GSM Rs.30/- Sq: ft
http://www.anutone.com/synthpf.htm

There are other suppliers supplying Polyfibre at:
1000 GSM @ Rs. 35/- sq: ft
500 GSM @ Rs. 20/- Sq: ft

* GSM = Grams per Square Meter.

Polyfibre:
Polyfibre is primarily a 95% re-cycled material which offers a reduced carbon footprint to your project and is non-hazardous and non toxic.
Poly insulation is also approved for use by the asthma foundation. Poly batts do not harbour or sustain the growth of fungi, bacteria or vermin.
100% fire resistant..

Today I was unable to meet Saint Gobain (Gyptone) dealer to discuss pricing of Gyptone Big Boards. Will meet him tommorrow...

 

[sdurani]

By absorption i have always thought that sound energy passes into something and weakens along the way.

It's converted via friction to heat.

If the water/air hits the sponge and the sponge was strands of fibers, it would come loose....eventually.....no?

Sure, but that's why you used it with care, by wrapping your panels in foam and cloth. It's not a question of whether fiberglass pieces will crumble, it's whether those strands will vibrate through the foam AND cloth to get into the air in the room. It's not easy going through both barriers. And IF they get into the air, will breathing them be bad for your health or simply an irritant?

"Experiments with rats have demonstrated a clear relationship between cancer and fiberglass when the fibers are surgically implanted, but not when they are inhaled. Industry representatives concede that surgical implantation is indeed a cause of cancer, but suggest that the studies showing a relationship between inhaled fibers and factory workers are invalid."

"In 2001 The International Agency for Research on Cancer (IARC) working group revised their classification of fiberglass from being a possible carcinogen to not classifiable as a human carcinogen. Studies conducted since the original report show there is not enough evidence to link fiberglass to cancer risk."

Fiberglass Insulation: Fiberglass Insulation: Use With Care - HealthyHouseInstitute.com

 

[sdurani]

There are clinical studies about glass wool being carcinogenic in mice..This is the reason why I am concerned despite it being an excellent acoustic material.

Then your concern is unfounded since: a) the mice got cancer only when surgically implanted with fiberglass, not by inhaling fiberglass, and b) fiberglass is not on the list of known carcinogens.

 

[john_k_antony]

I heard from someone who works with fiberglass that the fine fiberglass can get into your blood streams though hand when you handle them without gloves. These fine fiber glass that gets into the blood stream may cause cardiac related issues. So it is STRICTLY advised to use proper precaution when working with glass wool. You need to use gloves and nose masks.

-John.

 

[shelley]

@sanjay

Did you read the PDF file (US Government Report) link I provided above...
http://ntp.niehs.nih.gov/ntp/roc/twelfth/profiles/GlassWoolFibers.pdf
------------------
"Glass wool fibers caused tumors in two rodent species, at several different tissue sites, and by several different routes of exposure. Individual types of glass wool fibers were studied in chronic carcinogenicity bioassays in rats and/or hamsters exposed by a number of routes, including inhalation, intratracheal instillation of fiber suspensions, surgical intrathoracic implantation, and direct exposure to the pleural or peritoneal cavity by injection. The studies employed various glass wool products and treated or sized fractions of the products. Inhalation exposure studies used respirable fibers as defined by World Health Organization criteria (see Properties) unless otherwise specified. "
---------------

The information that you have that "mice got cancer only when surgically implanted with fiberglass" is absolutely wrong. Please read the whole report..

 

[pupupuchi28]

Shelley, this thread is quite informative! Thank you.

 

[Santy]

The chances of developing cancer due to glasswool is less than getting it by drinking coffee.

Well I am not saying, International Cancer Research Centre of WHO says so.

Does glass wool represent a health risk? / Glass wool / Q&A / Home - Isover

 

[sdurani]

The information that you have that "mice got cancer only when surgically implanted with fiberglass" is absolutely wrong.

Yes it was. Thanx for the correction. The report I had read conflicted with the W.H.O. report.

Please read the whole report..

When you first linked to it I skipped the begining and went straight to the part labelled Cancer Studies in Humans, which confirmed why the International Agency on Cancer Research (IACR) has removed fiberglass from its possibly carcinogenic to humans list:

"The nested case-control study of lung cancer among male workers found no evidence of an association between working in plants manufacturing glass wool fibers and respiratory system cancer".

And that's for workers in a fiberglass factory. If that level of exposure cannot be correlated to cancer, then properly wrapped panels are not a concern.

 

[shelley]

Re: DIY Room Acoustics for Home-Theatre

"Perforated Hardboard" can be used to cover the wood wool boards inside frames. Usually used by studios. When I visited the dealer today a person was buying hardboard in bulk for a studio project.
Standard perforated hardboard is made of wood fibers, usually with the addition of resin, and tempered by coating with a thin layer of linseed oil and baking at a high temperature to polymerize the oil. This provides more water and impact resistance, hardness, rigidity and tensile strength.

Perforated Hard Board:
Dimension : 4' x 4' = 16 Sq: ft
Pricing: Rs.280/- per board
Works out to Rs.17.50/- sq:ft
We can paste Burlap or Wool fabric over it and it will look pretty nice. Perforated hardboard can also be painted.
We can procure it from wholesale shops selling plywood/MDF...

Visited Gyptone dealer:
Saint Gobain Gyptone Big Board:
Dimensions: 6' x 4' = 24 sq:ft/- board
Price for Gyptone Big Board: Rs.360/-
Cost will be Rs.15/- per sq: ft
But the cost with framing for gypsum boards etc will cost approximately Rs. 65/- per sq: ft

Perforated Hard Board seems to be the Most Economical Option so far and commonly used by studios..

 

[shelley]

Ian Colquhoun, president of Axiom and chief designer of Axiom speakers, his views on the subject of overdoing room acoustics:

"The biggest mistake I've seen people make is their getting compulsive or fanatical and building special damped and/or reflective rooms for their home theater. I have been in some of these rooms (costing up to $250,000, and built by so-called professionals) and they are horrible-sounding. My theory is that we live in known environments and we are used to hearing sounds in these environments. For example, consider the sound of an acoustic guitar or even a clinking of wine glasses. We know what these sound like in our living rooms and outside. All these sounds become references of what we think these events should sound like. If you re-created these sounds or events in a "special" room, they would sound different, and hence unnatural. So avoid the danger of listening-room obsessiveness and don't change your room very much. I would suggest starting with small tweaks to get the bass right and the treble natural and clean-sounding, but don't go overboard or you can create an unnatural and hence bad-sounding room."

"And what of "bass traps," those expensive padded cylinders and screens that are sold to naive audiophiles and claimed to absorb problematic standing waves in the low bass? For the most part they don't work, because the wavelengths of low bass frequencies are so large that any "trap" would have to be of ungainly dimensions to become effective."
================================================================

I am finalizing my plans..Have chosen Wood Wool as my primary absorbing material, being eco-friendly and economical. Placed order and awaiting delivery.
Will provide more details soon including detailed price breakup...

 

[sdurani]

The chances of developing cancer due to glasswool is less than getting it by drinking coffee.

Less than coffee but same as tea. I don't know if I should start worrying about my afternoon chai.

 

[sdurani]

Ian Colquhoun, president of Axiom and chief designer of Axiom speakers, his views on the subject of overdoing room acoustics:

Floyd Toole's final paper before retiring approached the subject from the opposite direction, by discussing the benefits of naturally occuring room reflections:

http://www.aes.org/e-lib/download.cfm?ID=13686&name=harman

Section 9.2.1 is only half a page long but a must read for anyone interested in acoustics.

 

[manoj.p]

Just want to add my opinion on the fiberglass. This material is very itchy and cases skin and eye irritation. If you are not using long gloves while handling it, you will start itching badly in 5 minutes.

Now, imagine if the fiberglass powder is in the air due to speaker vibration. Even if you are not able to see it, your skin will start feeling it before it gets to your throat. So many people have used it in their setup and if they haven't complained about skin irritation, then most likely that fiberglass is not in the air. If it was, then it would be hard to sit for long time.

To OP: Not questioning your choice of wood wool here. I just want to clear some air about the fiberglass.

 

[narenkum]

I am finalizing my plans..Have chosen Wood Wool as my primary absorbing material, being eco-friendly and economical. Placed order and awaiting delivery.
Will provide more details soon including detailed price breakup...

Great Thread Shelley,

I have been watching this thread closely and I am very impressed with the way you have so for provided the details including the cost of the various options for choosing the absorbing material.

Will now wait for you to complete the work and your reviews on the new setup and will then try to replicate the same at my place. Hope there are no copyright issues:lol:

All the best for completing your setup and I am sure this will act as a reference for all of us in terms of Hygiene, Cost and aesthetics.

 

[shelley]

@narenkum
You need to pay royalty for the information provided

Following are the details regarding purchases of Wood Wool:

Manufacturer of Wood -Wool:

Vinardax Enterprises,
No: 17, Doddakallasandra, Kanakapura Road,
2nd left from Khoday Breweries,
Bangalore - 560 062
Ph: 080-26321289
Owner: Dushyant Patel
Mobile: 09448049966
http://www.vinardax.com/acoustical_materials/wood_wool_boards
e-mail: [email protected]
==========

Vinardax supplies most of the materials required for Home Theatre anywhere in India.

The following are the special rates at which he provides materials:

Wood Wool: 4 x 2 : @ Rs. 25/- per sq: ft + 14.5% CST which will come to:
Rs. 28.62/- per sq: ft
One Board is 8 sq: ft which costs Rs. 200/- per board + 14.5% tax = Rs.229/- per Wood Wool board (inclusive of tax)
Nobody supplies Wood Wool at these rates anywhere in India.

Compare this with Anutone Strand SS cost of Rs.75/- sq: ft . One Anutone Strand SS Board will cost Rs.Rs.600/- (inclusive of tax)
Cost saving per board, if purchased from Vinardax: is Rs. 371/- per board or Rs.46.40/- sq: ft
Multiply your sq: ft requirements with Rs.46.40/- and you will understand the cost savings...

For example, if you need 500 sq: ft for your project, you will save Rs.23,200/- if you buy wood wool from Vinardax rather than Strand SS from Anutone..You can spend the money elsewhere...

Comparison:
Anutone Strand SS Board (Wood Wool) costs: Rs.600/- per board
Vinardax Wood Wool Board Costs: Rs.229/- per board
The cost is nearly 62% more..Your gain = 62%

See how companies like Anutone bills you at exorbitant rates..

This the real advantage of DIY projects...

Vinardax supplies Polyfibre too as slabs:
Dimension: 600 mm x 1200 mm
1000 GSM @ Rs.35/- sq: ft
500 GSM @ Rs.20/- sq: ft
50 mm or 25 mm thickness

Foam Pyramid: 50 mm thick @ Rs.100/- sq: ft

Pre-laminated perforated MDF:

8 mm @ Rs.60/-sq:ft
12 mm @ Rs.75/-sq:ft
17 mm @ Rs.90/-sq:ft

Perforated Gypsum Board:
Micro or Macro Perforation:

Dimension: 6 x 4
Rs: 25/- sq: ft
Saint Gobain Gyptone costs Rs.40/- sq:ft for 2 x 2 boards

Call Mr. Patel of Vinardax and tell him that you are friend of Shelley from Trivandrum and he will give you at special rates specified above, which I have received for the materials after negotiations. Original retail rates are diffrerent @ Rs.40/- sq: ft for Wood Wool

The guy is a bit lazy and dull over phone. His staff is not that efficient and you need to push them a bit for speedy delivery. You can make fund transfer online and e-mail or call him and he will despatch the materials. I ordered yesterday and the materials were despatched yesterday itself.

 

[sap2nirvana]

Now this is really bad .............. wait a sec, i mean on my part.. being in Blore i couldnt find such place to get material for my build.
and since i read they have already shipped the materials, i believe you are going to use them for you build .. Keep us updated as usually you do with pics..

 

[shelley]

Re: DIY Room Acoustics for Home-Theatre

Good News..Wood Wool has reached Trivandrum. But courier (LR Copy) not yet received..DTDC couriers...Indian couriers are worse than snail mail of Indian Postal Service..:lol:

Checked with a Timber Godown for Wood (for creating frames). He has quoted Rs.13/- per feet and will cut it to size as required. Planning for 3" width to accomodate space between walls and to pack with wood wool (18 mm).
So only job required by the carpenter to create frames will be to stick it with Fevicol and fix joints with screws. Can also use wood stapler. I am going for fevicol and screws to avoid buying wood stapler...Cost Cutting..
A upholstery guy has promised to fix Hard Board and paste it with fabric tightly...Will post photos once I start work..

 

[sash]

About Mr Patel of Vinardax, i have had the exact same experience. On phone he appears to be uninterested and aloof, but is a great and honest chap when you meet him in person
Great information Shelley.