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How to sound proof HTS room ?

Wharfedale EVO4.1 Bookshelf Speakers

vint

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I was in office attending a meeting, when I suddenly realized I'm sitting in a sound proof room (eureka moment .... yay!). The telecon/discussion was going on at a high volume, yet nobody outside was able to hear anything nor were we able to hear any noise from outside. I did some observations and noted that the room had some basic woodwork and a heavy glass door. Is this enough to make a room sound proof ?

For ex: If I replace the wooden door of my HTS room with a heavy glass door will that ensure sound doesn't get out of the room and no external disturbances come in ? Or do we need to take care of something else ?

I might be moving to a new home in the coming months. So thinking of moving my HTS to a dedicated room. And if I can make it sound proof (like above mentioned), then there's nothing like it. It wouldn't cost so much and no more yelling from family members , neighbors to tone down the volume.

Please advise.
 

spirovious

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You can use certain absorbing boards made of like cardboard/partical boards.
Valvate like material can be used on door with damping in it.(sponge filled?)

Also thick carpet on groud.
 

vint

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ok, thanks for the suggestions. Spirovious, thick carpet sounds good. Can you elaborate on the cardboard/partical boards ? Are you saying I should be covering the walls with that ?
 

marsilians

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I think there is some confusion in the thread. you are confusing sound proofing with sound absorption. These are quite different.

Soundproof prevents sound from travelling through - the best materials for this are 'a layer of air', fiberglass sandwich, physical distance and heavy material like cement walls.

sound absorbtion uses various materials within a listening environment like heavy carpets, curtains, glasswool or foam to prevent or absorb sound waves and reflections. Unfortunatley these materials cannot combat low frequencies such as coming out of the sub out.

With this, what is it you are looking for in the above?
 

smedhavi

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marsilians is right.

For sound proofing I have double glass windows, with 1.5 inches of air in between, and a layer of foam on the inner side. This is covered by thick cotton curtains. These windows are opened only once in a while to freshen up the air when the HT room is not in use.
I have thick cement walls, while one of my friends, who does not have the tree cushion between his house and the next the way I have, has double concrete walls with air cushion in between.

Thanks,
Sharad
 

spirovious

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ok, thanks for the suggestions. Spirovious, thick carpet sounds good. Can you elaborate on the cardboard/partical boards ? Are you saying I should be covering the walls with that ?

Yes,you can hang on wall,door to prevent leakage.
I read article in av max abt this.Even some frames with absorbing materials to get good look of room.
 

spirovious

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I think there is some confusion in the thread. you are confusing sound proofing with sound absorption. These are quite different.

Soundproof prevents sound from travelling through - the best materials for this are 'a layer of air', fiberglass sandwich, physical distance and heavy material like cement walls.

sound absorbtion uses various materials within a listening environment like heavy carpets, curtains, glasswool or foam to prevent or absorb sound waves and reflections. Unfortunatley these materials cannot combat low frequencies such as coming out of the sub out.

With this, what is it you are looking for in the above?

correct,but I suggested it as it will further help.
As thick carpet,boards can absorb sound,reflecting waves can be cut off.
So leakage can be minimised.
 

venkatcr

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I might be moving to a new home in the coming months. So thinking of moving my HTS to a dedicated room. And if I can make it sound proof (like above mentioned), then there's nothing like it. It wouldn't cost so much and no more yelling from family members , neighbors to tone down the volume.

Vint, if you are serious about this, there are companies that make special material to be mounted on the wall. For doors, they have a special fabric that can reduce the transmission of sound either way. This fabric has to be stuck all over the door.

One inexpensive method I have seen being done is to stick glass wool on the door, and then mount a rexine on top much life a sofa stuffing.

For material please look at the following sites:

Rockwool - GAJRA GLASSFIBRE PVT. LTD.
Twiga Fiberglass Ltd - Home
Thermal Insulation Board,Heat Insulation Board,Thermal Insulation Board Manufacturer,Heat Insulation Board Exporter
Anutone - makes you feel good

These material will cost you somewhere from 150 to about 500 Rupees a square feet. This includes material, fabric, and mounting costs. Anutone makes some superb material, but they are very very expensive. Fibretex makes good material at reasonable rates, but would need extra work for mounting.

Cheers
 

santhosh

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Thanks for this info venkatcr.

I am constructing a Home Theatre Room and would like to acoustically treat my room. I intend to address both 'sound proofing' and 'sound absorption'. Any idea where these materials or similar can be sourced in Bangalore. Anutone is beyond my budget at around Rs.250 per sq.ft installed. I am looking for something less expensive even if it involves DIY effort and hiring a carpenter.

I am particularly interested in this material:
Roof Insulation Board,False Ceiling Panels,Roof Insulation Board Manufacturer,False Ceiling Panels Supplier

When I called fibretexindia, the executive advised me that they did not have any dealers in India. He also mentioned that this would cost around Rs.60 per sq ft for 20mm thickness and around Rs.65 per sq ft for 25mm thickness(further discounts at time of order based on quantity).

Before, I order the material and ship it from up north, I would like to see this save on shipping if these are available in Bangalore. Recently, I even it used for no particular 'acoustic' purpose in a restaurant in Bangalore. I am sure these materials must be used in Industrial applications and must be available locally. It might just be that the local names are different.

Also feel free to suggest other 'Value for Money' techniques to achieve the same results.
 

venkatcr

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Santosh:

TWIGA makes similar material and ships them across the country. They have an office in Bangalore.

One way to do this inexpensively is to make a small wooden frame (2 to 3 inches thick) and mount rigid fibreglass on the front. The empty area at the back can be filled with loose fibreglass that is available locally. Cover the whole thing with a nice cloth and you have a good sound trap in place.

TWIGA sells the material as follows:

Twiga 32kg/cub. m 25mm thickness (this comes as a roll)
Twiga 48kg/cub. M 50mm thickness (in a box, rigid)
Probably even the 32kg density glasswool you can get it in a box if it is 50mm thickness so specifically ask for it in a box.

The boards comes in a box with boards of roughly 3 feet by 4 feet. The whole box is some 1200 Rs.

Cheers
 

hubballi

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Santosh:

TWIGA makes similar material and ships them across the country. They have an office in Bangalore.

One way to do this inexpensively is to make a small wooden frame (2 to 3 inches thick) and mount rigid fibreglass on the front. The empty area at the back can be filled with loose fibreglass that is available locally. Cover the whole thing with a nice cloth and you have a good sound trap in place.

TWIGA sells the material as follows:

Twiga 32kg/cub. m 25mm thickness (this comes as a roll)
Twiga 48kg/cub. M 50mm thickness (in a box, rigid)
Probably even the 32kg density glasswool you can get it in a box if it is 50mm thickness so specifically ask for it in a box.

The boards comes in a box with boards of roughly 3 feet by 4 feet. The whole box is some 1200 Rs.

Cheers



Hello Venkat Sir and Santosh,

I dont want to hijack this thread or divert attention....So please pardon me.

I am having reverbaration problem is one side of the sitting area (just next to the wall) where I have my HT set up. For people sitting there the Sub sound is very boomy. Should I be using same material as sound absorbers or there is something specific available?

I tried moving the sub around but current location is the best I could manage.


Please advice.

Thanks in advance

Regards,
Arun
 

santhosh

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Santosh:
TWIGA makes similar material and ships them across the country. They have an office in Bangalore.

Thanks Venkat, I gave them a call today. I will visit their office in Bangalore this weekend to checkout their products.

Hello Venkat Sir and Santosh,

I dont want to hijack this thread or divert attention....So please pardon me.

I am having reverbaration problem is one side of the sitting area .....................current location is the best I could manage.
My knowledge in this area is only half-baked and is based on what I have read online. I think sound absorption should address your issue. Will wait for the experts to give you a solution for this problem.
 

venkatcr

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I am having reverbaration problem is one side of the sitting area (just next to the wall) where I have my HT set up. For people sitting there the Sub sound is very boomy. Should I be using same material as sound absorbers or there is something specific available?

I tried moving the sub around but current location is the best I could manage.

Arun:

This is essentially the wall acting as a big reflector and reflecting the sound from your speakers. If you have a parallel wall nearby, then most probably the sound is bouncing off both walls and creating what is called a standing wave.

If you sub is near a 90 degree corner, then you may need a simple bass trap to be set up in the corner.

Cheers
 
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hubballi

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Arun:

This is essentially the wall acting s a big reflector and reflecting the sound from your speakers. If you have a parallel wall nearby, then most probably the sound is bouncing off both walls and creating what is called a standing wave.

If you sub is near a 90 degree corner, then you may need a simple bass trap to be set up in the corner.

Cheers



Thank you Venkar Sir. Yes there is a wall parallel to it. Based on your feedback I started reading on the web and I found couple good links which might help other members too.

DIY BASS TRAPS - Index
Bass Traps
Build an awesome bass trap


I will read more and see what I need to do. I will surely update the progress and results.

Thanks.

Regards,
Arun
 

santhosh

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TWIGA makes similar material and ships them across the country. They have an office in Bangalore.
.......

Twiga 32kg/cub. m 25mm thickness (this comes as a roll)

I visited the Twiga dealer during the week and got a sample of their 32 kg/cubic metre 50 mm thickness. I will post a picture later today.

One way to do this inexpensively is to make a small wooden frame (2 to 3 inches thick) and mount rigid fibreglass on the front. The empty area at the back can be filled with loose fibreglass that is available locally. Cover the whole thing with a nice cloth and you have a good sound trap in place.

The Twiga dealer is also a stockist for several other acoustic materials. He did not have the woodwood board that I was after. So, instead of rigid fibreglass, can I use a peg board (perforated wood board) to cover the front of the wood frame and then cover them with a nice sound transparent cloth? I remember seeing this in some old theaters and also some recording studios. Please correct me if I am wrong. I am assuming you are using the rigid fibreglass only because it is stiff, so I will have shape to fit a cloth against.
 

venkatcr

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So, instead of rigid fibreglass, can I use a peg board (perforated wood board) to cover the front of the wood frame and then cover them with a nice sound transparent cloth? I remember seeing this in some old theaters and also some recording studios. Please correct me if I am wrong. I am assuming you are using the rigid fibreglass only because it is stiff, so I will have shape to fit a cloth against.

This depends on the sound absorption you are looking for.

The acoustical property of a material is measured by it's sound absorption coefficients as various frequencies. The absorption coefficient of a material is the fraction of the random sound power which is absorbed, or otherwise not reflected. Generally, the coefficient is measured at the preferred octave frequencies over the range of at least 125Hz - 4kHz. When a material has a coefficient of 1.0, it absorbs all sound between these frequencies.

Generally the sound absorption coefficient should be as follows as shown various frequencies.

125Hz - ~0.1
250Hz - ~0.2
500Hz - ~0.3
1000Hz - ~0.4
2000Hz - ~0.6
4000Hz - ~0.9

Wood board does not have good sound absorption coefficients. For frequency range from 250Hz to 500Hz it is 0.10, and 1000Hz to 2000Hz it is 0.30. Though it will provide some absorption, it is not ideal. Look for a material that has the sound absorption coefficients as near the figures I have shown above.

Cheers
 

santhosh

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Thanks Venkatcr for that information.

I came across this site recenntly which listed Absorption Coefficients of several products/materials. Thought I'll share it with everyone: http://www.bobgolds.com/AbsorptionCoefficients.htm

Is it a good idea to cover the fibreglass with a medium thickness polythene cover before mounting it into the frame? I read While reading online, I see that many use products which have been made similarly.

For Eg: Poly-Encapsulated - Insulation Products

I have read mixed reviews about using Fibreglass and also a somewhat non-conclusive reading that Fibreglass is hazardous to health. I am worried about Post No 11 in this thread on avsforums:
http://www.avsforum.com/avs-vb/showthread.php?t=1018700

Perhaps the reason why Dupont sticks a layer of "tissue paper like material" in front of their fibreglass. See picture of IndianEar's installation here
http://www.hifivision.com/av-enhanc...suggest-false-ceiling-option-3.html#post61311

I am unable to locate Dupont Fibreglass in Bangalore. Any leads please?

Also, I had visited Srisha's Home Theatre a while ago and found that Anutone uses a white colored sound-proofing material which they call Synth. What is the local name for this material? Is it Polyfill? Is it the same as used the material used in new-age Pillows?
 
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venkatcr

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Is it a good idea to cover the fibreglass with a medium thickness polythene cover before mounting it into the frame? I read While reading online, I see that many use products which have been made similarly.

I suppose there is no harm in doing that. But remember, any thing that is not acoustically transparent will affect the sound absorbing capabilities of the material.

I have read mixed reviews about using Fibreglass and also a somewhat non-conclusive reading that Fibreglass is hazardous to health.

Yes fibreglass is hazardous to health, but modern material are not as dangerous as made out in the AVS Forum. If you use rigid fibreglass in the front and fibrewool rolls in the back without splintering, there is hardly any chance of flying objects. Even at the back, the fibrewool rolls can be covered with thin cotton sheets before being inserted into the frame.

You can always use rockwool. Another option available in India is flexible boards made from a rubber compound, but this is expensive.

I am unable to locate Dupont Fibreglass in Bangalore. Any leads please?

Also, I had visited Srisha's Home Theatre a while ago and found that Anutone uses a white colored sound-proofing material which they call Synth. What is the local name for this material? Is it Polyfill? Is it the same as used the material used in new-age Pillows?

Contact the following and find out their dealers and contact in Bangalore:

Dupont Indian (P) Ltd.
10th floor - Meadows
Sahar Plaza Complex
Andheri Kurla Road,
Andheri (East)
Mumbai - 400 059

Phone: +91-22-67515000
Fax: +91-22-28393960

Anutone make their own boards by layering, gluing, compressing natural fibres to make the boards. These are covered with various options as per your choice. You can use fabrics of various kinds or use synthetic material offered by the. You will get more details at Anutone - makes you feel good.

Cheers
 

opert

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Hello all.. First time posting on the forum.

Santhosh, Please list/PM the info on Twiga dealer(s) and do you have any ballpark pricing info? Any luck with locating the Dupont dealers in Bangalore?

I am looking for the mineral/glass wool boards and/or sheets to complete my HT and would appreciate any help.

Thanks!
 
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santhosh

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Hello all.. First time posting on the forum.

Santhosh, Please list/PM the info on Twiga dealer(s) and do you have any ballpark pricing info? Any luck with locating the Dupont dealers in Bangalore?

I am looking for the mineral/glass wool boards and/or sheets to complete my HT and would appreciate any help.

Thanks!

Welcome to Hifivision Opert:)

Twiga dealer in Bangalore is:
Himal Supply (India) Private Limited
#41, 4th Cross,
Bender Nagar,
Bangalore 560 070.
Tel: (91 80) 2666 5441
Fax: (91 80) 2666 5441
email: twigabangalore@vsnl.net

They also deal in other Thermal and Acoustic Insulation products like Rockwool, Bitunil etc.

As a ballpark, I was quoted of around Rs.150/sq metre for the Twiga 50 mm thickness - 32 kg/cubic metre fibreglasswool board. Discount available on quantity. This product is sold in rolls while the much denser 50mm thickness - 48kg/cubic metre board comes in a box. I forgot the price for the 48 kg density one though:confused:
 
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