My success stories with acoustics treatment

[Ravindra Desai]

Hello all,

I am listing a few of my success stories with pictures.
I hope that you all will benefit from it

Glasswool panels covered with porous jute cloth was used in all cases. MDF board panels were used to hold the glass wool.
I will always be using this no matter what. What changes from case to case is the application (speech, stereo listening, movie watching) and the ratio of absorbing area to reflecting area.

Attached are pictures of some work/ cases that I did:

1. Heera Shri Residency Club House, Kolhapur, Maharashtra: There was so much echo that the builder was not in a mood to set the ribbon cutting dates. The opening ceremony was to be carried out in the club house of this posh gated community. He wanted good looks too.
I did the panel work calculations and worked with the builders architect for aesthetics. Used white Ahuja speakers to hide them in the colour scheme and powered it with my ampli processor (40Wrms with LMT). Problem was solved to the satisfaction level of the builder. ref photos 1-4

2. Keshav Smriti Hall, Chikkodi, Karnataka: After spending 4 crores to build the hall and another few lacs for the ceiling (which did not help the acoustics), the hal simply was unable to attract any clients for functions.
I worked on whatever limited space that was available, used heavy treatment with big NRC, and using a simple design solved the acoustics. So much so that the board prresident called me after they successfully conducted a classical music program where Shridhar Phadke was the guest singer.
Used Ahuja 4 x 15" full range speakers near the stage and angled them so that they covered the area correctly. Two on each side of the hall. Powered them with my ampli-processor 40Wrms for lower speakers and 80Wrms for the higher speakers. ref. photos 5-7

3. Niks Bass, Ichalkaranji, Maharashtra: The owner has a small time audio shop. His rented space was booming and he was in a jam as the rent was already catching up on him. I used the open wall spaces. Kept the design simple of the purpose of cost. Booming was gone and he was happy that he could now conduct demos nicely. I did not supply any sound system in this case. ref photos 8-9

I hope that you like this.

Regards,

Ravindra.

 

[panditji]

Nicely done sir... Can you help with aesthetically done bass traps to be put in 2 corner in a regular living room?

 

[prateekatasniya]

I have experienced irritation in eyes due to glass wool in a 1 year old home theater.

 

[sdurani]

Nice work! Making room treatments attractive is no easy task. Only suggestion I would make is to move some of the speakers forward to the front edge of whatever they're sitting on. This will keep them from reflecting off the surface and muddying the sound.

 

[Ravindra Desai]

I have experienced irritation in eyes due to glass wool in a 1 year old home theater.

No complaints from any of my clients.

Nice work! Making room treatments attractive is no easy task. Only suggestion I would make is to move some of the speakers forward to the front edge of whatever they're sitting on. This will keep them from reflecting off the surface and muddying the sound.

Suggestion noted. Thanks!

 

[z@m]

I have experienced irritation in eyes due to glass wool in a 1 year old home theater.

This is a known issue (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2739167/).

I have used dacron (pillow stuffing) in the past with satisfactory results.

 

[Dr.Lakshay]

I have experienced irritation in eyes due to glass wool in a 1 year old home theater.

Glasswool does have a health hazard not just the eyes but also for the respiratory system. It wouldn't be recommended to use in the home Atleast. Commercial areas may get away with it because no one is gonna live there. But you live in a home, and long exposure causes the hazards.

 

[prem]

Agreed. I would definitely stay away from use of glass wool at home

 

[Ravindra Desai]

Thank you for your concern.

Glass wool is proven to be non-carcinogenic.
US Government does not ban use of glass wool.
There is no ban on use of glass wool like there is on asbestos and lead.

https://www.ncbi.nlm.nih.gov/pubmed/10536105

However, it is up to the individual to make his choice, just like cigarette.

Regards,

Ravindra.

 

[rajesh srinivas]

This is a known issue (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2739167/).

I have used dacron (pillow stuffing) in the past with satisfactory results.

This is a known issue (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2739167/).

Its called Recron Poly fibre From Reliance Industries Ltd .

 

[prateekatasniya]

Thank you for your concern.

Glass wool is proven to be non-carcinogenic.
US Government does not ban use of glass wool.
There is no ban on use of glass wool like there is on asbestos and lead.

https://www.ncbi.nlm.nih.gov/pubmed/10536105

However, it is up to the individual to make his choice, just like cigarette.

Regards,

Ravindra.

Hi..

I'm Dr. Prateek Atasniya.

Yeah. Just like cigarette, Glasswool is harmful, irritant.

 

[tuff]

can foam be used as a replacement?

 

[Ravindra Desai]

can foam be used as a replacement?

Hello,

Sound absorbing materials are generally associated with a parameter called NRC, short for noise reduction coefficient and a graph of frequency vs NRC. NRC for materials used for acoustics treatment purpose ranges from 0.5 to 1. It helps the acoustics engineer calculate the material thickness needed, absorbing area needed to solve the issue for a given site.
Foam is a very generic term. Unless the NRC and NRC vs Frequency details of a particular type of foam is not known, it will be difficult to take a call.

Regards,

Ravindra.

 

[Dr.Lakshay]

Hello,

Sound absorbing materials are generally associated with a parameter called NRC, short for noise reduction coefficient and a graph of frequency vs NRC. NRC for materials used for acoustics treatment purpose ranges from 0.5 to 1. It helps the acoustics engineer calculate the material thickness needed, absorbing area needed to solve the issue for a given site.
Foam is a very generic term. Unless the NRC and NRC vs Frequency details of a particular type of foam is not known, it will be difficult to take a call.

Regards,

Ravindra.

What about wood wool acoustic panels?

 

[Ravindra Desai]

What about wood wool acoustic panels?

I am aware of Anutone that makes wood wool panels and also supply a datasheet with their products. It was used in Sangam Theater (closed now) in Kolhapur, when it was last renovated. I had installed my sound system there.
The results were very good.

The material cost + labour to install the tiles with correct geometry for wood wool tiles turns out to be very expensive.
The cheaper tiles are obviously the ones with low NRC and no colour.

Regards,

Ravindra.

 

[drkrack]

What about wood wool acoustic panels?

I used woodwool for my Hometheater Room after lot of researching, (My better half is allergic to many things) more than a year Now, No issues whatsoever, there is a risk of termites though! It works out lot Costlier than others.
Avoid Rockwool mostly, Glasswool bit subjective decision.

 

[zimbly]

Synth PF from Anutone is an excellent substitute for Glasswool. I was initially apprehensive on trying out Synth PF. But have used it extensively in my HT room. Only place I used Glasswool was below the riser and wall adjascent to the L&R speakers(To minimize boundary loading as my speakers are close to the wall). It is definitely more expensive. 2.5times the cost of glasswool. But it has none of the irritants associated with glasswool. The initial 6 months, I did encounter eye irritation, but was not sure if it was glasswool related or the glue used for carpeting the flooring.

 

[Ravindra Desai]

Hello all,

The week before last, I completed another site that had severe acoustics related issues and speech intelligibility was bad.

Site: Gujrat Bhavan, Hubli, Karnataka

Problem statement: The multipurpose hall was renovated 2 years back and the board had spent around 10lacs on beautification using POP, chandeliers and decorative stones. A lot of glass windows were used for ventilation. The hall looked beautiful but you just could not hear anything said from the stage.
Since the multipurpose hall was mostly used as a marriage hall, acoustics related issues did not get priority.
When the committee decidecd to host a Guruji to recite Bhagwat Gita and as he was very particular about sound and acoustics, I was found!

Challenges: Time frame of 25days and limited budget. Ceiling and stage could not be treated because it was a large part of the beautification and time and budget constraint

Solution: I analyzed the type of reflections and identified the places where I could treat the hall using my sound absorbing panels. I took a close look at the windows and found that they were of the sliding type and simple arithmetic told me that at any given time there was 50% of the window that always remained shut. I needed 35% non-reflecting area and suggested that they use 3-part, thick, natural fabric curtains that would cover the glass portion when the windows were opened.
Also, I was counting on the non-continuous POP ceiling design to help the acoustics and it did!

Result: I completed the assignment 2 days before the function. 4 days later than my calculated schedule. I thought I would get adjustable pipe scaffolding, but instead got fixed, old style bamboo one. The landing heights were inconvenient to work. I also had to work with local labor at their pace and timings. But in the end it went well.

The function went without a hitch and without a single complaint about sound intelligibility. I was as happy as those guys on solving this tough assignment.
I have to admit, even after so many installations, there is always a lump in my stomach till all the panels get installed in its place and add to the aesthetic value.

Attached are some photos for your ready reference. These were taken while I was on site and before the scaffolding came off. Also the curtains were not in place yet.

I hope that you like my work!!

Regards,

Ravindra.

P.S. I am posting this after talking to the hall trustees about the success of the program.

 

[Ravindra Desai]

Hello all,

Last month an opportunity knocked my doors. This time it was a Gym in Kolhapur. The Gym is part of a gated community. The area is about 800sq. ft.
The biggest challenge was that it had glass panels all around , low ceiling and heavy echo that caused headaches within a few minutes.

The builder understood the importance of acoustics treatment. before fitting any sound system.
The challenge was fixing the panels on the wall as there was lot of glass.
I went there in the evening and sat looking at the structure and came up with an idea of using pivots.
The client, being a builder, had good contacts with accessories stores and agreed to get me the fitments that I needed.

The sound system uses my, now famous, 3" full range speakers (4 nos) and a 12" subwoofer. The configuration is 2.1 Stereo and the amplifier is 3 x 20Wrms/ CH.

The result is in the attached photos.
The room acoustics is improved to an extent that you can conduct any type of meeting or gathering.

There is plenty of volume, good bass beats (the sub is unlocatable to the extent that people think it is the 3" speakers that is producing everything!!) and everybody from the builder to gym instructor to the visitors and occupants are very happy.

This is the first type of installation I have done where the acoustics panels swing open or close like vertical venation shutters and my first Gym installation.

Points to note:
1. Swinging acoustics panels
2. Almost invisible satellite speakers
3. Hidden subwoofer with the ampli-processor placed on top of it
4. Overall aesthetics

I hope that you like it.
Thanks!!

Regards,

Ravindra.

 

[tuff]

Those swinging panels are a great idea....congratulations.