Urgent Help Required

Hey All....

I m planning to put a glass wall on the back of the sitting area ie. in front of the TV screen / projector screen.... will there be any audio loss.. and wht shall be the minimum thickness of glass so that it doesnt break when i m playing audio louder

Hey Pranab

Hws ya...???

How did your wiring go...???

And hws the progress goin on...

sorry couldnt plan the visit to your place...
Anyways... for your information.. i have added... 3 more brands in my basket...
and now.. i am even importing a few products...
soon will plan to your place...

Sorry regarding the glass.. thing...
i think...
Vinay, Soundsgreat & others should be more helpful...

Hi,

having (large) glass surfaces in a listening room is never a favourable thing, having it behind the listening position is even worse... try and hear.

Regarding the glass thickness; no idea. I think it depends a bit on the size of the glass wall, its construction whether in one peace or with supports in between the surface, the room's dimension, what acoustic pressure your speakers / woofers, corresponding to the loudness, might create and what modes (bass) you have in that area.

However, standard thickness used for larger cabinets i.e. should make it (3-4 mm?) If in doubt take window-glass.

Well, will be intresting what other people would suggest here.

Brgds
nuRoXX

Pranab, though glass has good acoustical properties and can act as a good sound barrier.

But before we go into the details, I want to understand what is that you want to achieve with the glass wall. I am particularly intrigued by your statement 'in front of the TV screen / projector screen'. Does this mean between the screen and the viewer? If so what is the purpose?

Cheers

Hey...

well the glass will be behind the viewer seat ie. the back wall.... and im planning to have a glass wall instead of an concrete wall... as the glass wall is better for sound absorbtion and also if i install the glass wall... the looks of the home theater will also become... from my living room.....

The acoustical properties of an objects are measured to see how much sound they absorb and how much sound they reflect. Each object is assigned an absorption coefficient which is a number. A rating of 0 (zero) means all of the sound is reflected. A rating of 1 (one) is total absorption.

Glass is a brittle, transparent, and solid material, It's sound absorption coefficient is as follows:

0.35 at 125 Hz
0.25 at 250 Hz
0.18 at 500 Hz
0.12 at 1 KHz
0.07 at 2 KHz
0.04 at 4 KHz

Glass absorbs more at low frequencies and reflects more at higher frequencies. Glass physically moves at low frequencies, generating heat, and thus creates a loss of the acoustical energy. Glass can, in this process, also transfer some of the energy to the other side. As you may be aware sustained high frequencies can also shatter a thin glass.

Now look at a concrete wall. Here are it's coefficients,

.36 at 125 Hz
.44 at 250 Hz
.31 at 500 Hz
.29 at 1 KHz
.39 at 2 KHz
.25 at 4 KHz

As you can see, a wall absorbs sound at most frequencies. In other words,, it acoustical property is fairly consistent across the frequency range. This is an unpainted wall. The minute you paint a wall, it becomes reflective. It coefficients range from 0.05 to 0.10 across the frequencies. If you are building a wall, it is better to leave it unpainted if you want the sound to be absorbed.

Neither a wall, nor glass is very efficient with managing sound. If you want very good room acoustics, you must use special material prepared for this. This can be mounted either on a brick wall or on wooden panelling.

If you really like to use glass for the wall, use glass sheets that have been made of multiple panes stuck together. This will be less expensive than a thick single pane glass sheet. Multiple pane glass sheets have better acoustical properties.

Cheers

I am going to piggy back on this thread to post a glass related quesion - I hope that's all right.

My listening room is 13 by 20 feet, I have my projector screen and front speakers on the front wall. One of the sidewall faces a busy road. I have a glass window close to the screen end of the room and a glass sliding door which opens into the balcony at at the other end on this side wall.

I am going to seal off the window with glass wool and ply wood. I can't do the same for the sliding door.

The Sliding Door is about 6' by 7', which I plan to replace with a better sound proof solution.

I have looked at Acoustic Glass from Asahi, but the minimum size they sell is twice my requirement and costs around 26,000 for the glass.

Alternatively, I can use double glazing IGP glass which is much cheaper but the air gap is only 10 mm.

A cost effective solution could be to use Secondary Glazing, two fixed frames with 12 mm and 8 mm glass in each frame with a 7 inch air gap and have two glass doors one opening into the room, and the other opening out.

I don't want to spend too much money, and want a solution which gives me 38 to 40 db STC

any expert advice would help a lot

Instead of sealing off the window, look at hanging heavy drapes. They are good option. In India, a completely sealed room is not common. We need air, and we need to clean, and we have objections from all our family members. My wife, for example, has keep a large door in my HT room open ALL the time. Sigh!!!

This is not an expert solution but just a possible alternative. One option is to replace the sliding glass with sliding wood panels. On top of the wood panels, you can stick thin glass wool sheets and cover that with a nice fabric. You can nail veneer to the sides to hold the fabric and also look nice.

Another option is to use soundproof fabric, that can just be pasted on top of the panel. The corners can be nailed with a veneer to both hold the fabric and to look good.

Materials are available from UP Twiga Fibreglass Limited (Twiga Fiberglass Ltd - Home) or from Anutone (Anutone - Enhancing Living Experiences). Anutone also has soundproofing curtains.

You have to be a little patient when dealing with these companies. They usually deal with large clients and will not pay much attention to small fries like us. Anutone stuff is very beautiful, and provides high sound absorption coefficient.

I am sure if you look around in the local market you might find some dealers/distributors who sell glass wool sheets.

Cheers

I have two windows in the room, so sealing one should not be a problem.

I got in touch with Twiga for Fibre glass and got a very quick response! Thanks for the lead.

You are welcome. Please keep us updated on your room acoustic progress.

Cheers