[cr-india] acoustics

Tue May 15 11:37:27 CEST 2007

Dear Jean:
We've been using the egg tray technique that Vickram mentions, glueing 
the trays directly onto walls and ceilings, with a middle thick rug or 
carpet on the floor. It gives excellent results, especially if you use 
fresh trays (straight from a poultry wholesaler): Spray them with bug 
spray and put them out in the sun for a day before using them. (Warning: 
You'll have to hold each tray in place for a while while the glue dries. 
Fevicol or similar white adhesives work fine, as do epoxy based glues 
like Araldite or Fevibond. The white adhesives work out more economical, 
especially if you have large surfaces to cover.)
We've also experimented a bit with the studios we've built with our 
Uttarakhand radio groups by stretching a thin layer of foam sheet over 
the egg trays once they're in place. Seems to damp the sound a bit more, 
but haven't tried this in a medium sized room yet. (Should work.) The 
foam sheet is available in most furniture shops in 1", 1.5" and 2" thick 
rolls. The width of the roll usually ranges from 2.5 feet to 4 feet.
Use the egg trays with the side into which the eggs go facing into the 
recording space. Apply glue to the projections on the other side - the 
more the better - and slap them onto the wall. If your wall is flaky or 
damp, Vickram's suggestion that you create a second wooden battening 
within the main wall is the perfect solution: We did just that for our 
field studios. (It's a lot easier pasting the trays with glue onto plywood!)
There are small handle type indentations on two of the opposing edges of 
most egg trays. Use those indentation to align the trays and orient them.
My two bits!
Ram

N.Ramakrishnan

Director of Projects
Ideosync Media Combine
177, Ashoka Enclave III
Sector 35, Faridabad - 121003
Haryana - India
Tel: +91-0129-4131883/6510156/2254395/2254396 (Prefix 95129- from Delhi)
Telfax: +91-0129-2254395 (Prefix 95129- from Delhi)
Mobile: +91-9810273883
Email: nram at ideosyncmedia.org

Vickram Crishna wrote:
> Thermcol sheets are reflective comparatively, but not
> thermocol peanuts stitched into quilts. 
>
> There is an inexpensive new foam material used by
> flowersellers to support cut plants, but it is very
> hygroscopic and also I have no idea where to get it.
> It is soft and easy to cut shapes with a hobby knife.
> I would try holding it to the wall with
> washers/screws. 
>
> To address Mahesh's water concerns, if the wall is
> such poor quality that it gets soaking wet, you are
> better off moving to an inside room if possible (this
> will also cut down on outside sounds). 
>
> If not possible, you can isolate your acoustic
> dampening from the rain dampening using cheap wooden
> battens nailed to the wall, and glueing/nailing the
> egg trays to the battens. 
>
> --- jean parker <radioforever at gmail.com> wrote:
>
>   
>> All:
>>
>> Understanding that thermocol is reflective, what is
>> a common foam material that is acoustically
>> absorbant, inexpensive and readily available? 
>> Please give the name and places where it can be
>> obtained.
>>
>> Thanks,
>>
>> Jean
>>
>>   ----- Original Message ----- 
>>   From: Mahesh Acharya 
>>   To: jean parker ; cr-india at sarai.net 
>>   Sent: Monday, May 14, 2007 10:27 AM
>>   Subject: Re: [cr-india] acoustics
>>
>>
>>   Hi Jean and all  in  this group.
>>
>>   Two points that you may want to consider when
>> using egg crate made of cardboard. To avoid damage
>> to the egg crate material due to water from wall
>> (walls tend to become damp in monsoon) make sure
>> that there is at least half cm gap between material
>> and wall. I would advise that you treat the material
>> with pesticide. The material is made of cellulose
>> and termites/insects would damage the it. 
>>
>>   Adding to Vikram's concern about thermocol being
>> highly flammable, thermocol would reflect the sound
>> and affect the recording. 
>>
>>   regards,
>>   mahesh
>>
>>
>>   On 5/13/07, jean parker <radioforever at gmail.com>
>> wrote:
>>     Hi All:
>>
>>     Sent this before but I don't think it got
>> through.
>>     Does anyone on the list have experience with
>> using egg crate materials and
>>     thermocol for studio rever reductionand sound
>> proofing?  I know it has been 
>>     mentioned on this list before.  If soI would
>> like to know if people have
>>     designs they could share and also resources for
>> getting materials.
>>
>>     Many thanks,
>>
>>     Jean
>>     
>
>
> Vickram
>
>
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