Sunday, December 20, 1998 10:59:52 PM
From: GSBN@...,Txinfinet Incoming
Subject: Digest for 12/20/98
-> Re: Sound "Tests" SB Walls Longish
by "Rene Dalmeijer" <rened@...>


Date: 20 Dec 1998 15:52:22 -0600
From: "Rene Dalmeijer" <rened@...>
Subject: Re: Sound "Tests" SB Walls Longish

Thanks Noise wolf,

These are the very first actual figures for SB structures. I expect that SB
walls can perform quite a lot better then you measurements indicate. The
problem is a building is nor only walls its also doors airco etc. As you
state yourself you can have serious sound leaks from some very small vents
or cracks.

I think if you pay careful attention to doors and other junctions you could
improve performance tremedously maybe another 10-15 dB. To measure correctly
you should also use a calibrated sound source. A rock band generates a lot
more low frequency sound than general noise. Sound sources also come in A
and C weighted variaties. The A weighting conforms to 'normal' human hearing
responce. We are less receptive to high and low frequency and have a
pre-occupation for about 1000Hz corresponding to human voice. If measuring
it is a good idea to measure octave bands sperately too. This gives a better
impression of what you are measuring and what building and measuring
mistakes have made.

Rene Dalmeijer
- -----Original Message-----
From: Huff and Puff Constructions <huffnpuff@...>
To: (email address removed)<strawbale@...>
Cc: (email address removed)<GSBN@...>
Date: Saturday, December 19, 1998 9:38 PM
Subject: Re: Sound "Tests" SB Walls Longish

>G'Day One and All
>My you are all busy writing these days must be something to do with the
>long dark nights. Obviously we are in mid summer and have to work for a
>living. I have not been able to keep up with my normal email let alone
>this list, some wonderful posts I only wish that I could put my two bobs
>worth in.
>We have just completed testing the sound qualities of "The Practice
>Pad". The Practice Pad consists of three sound recording studios in
>Surry Hills, an inner Sydney Office and Residential area, that we built
>two years ago for Bruce Thomas. The Studio is located on the third
>floor of a 6 storey office block. There are five straw bale walls 450
>mm thick (18") which were sheeted in Gyprock 10mm on a 4x2 timber stud
>wall. Each room has a double cavity door 450 mm deep no windows and a
>wall mounted air conditioner.
>The University of Technology Sydney kindly lent me the equipment to
>measure the sound levels. We need these results for the College of
>Sustainable Building (Straw Panel Factory) that we will build in 99 in
>Ganmain in the middle of the village. The walls of the College will be
>900mm (3') thick, the machinery in the factory (college) will consist of
>a very large band saw run by an electric motor solar powered.
>The tests on The Practice Pad was carried out by myself with a couple of
>witnesses, no cheating was allowed. The instrument was a Radio Shack
>Sound Level Monitor made in China under a Canadian licence, does that
>make it Canadian? I used two weightings in the tests in the studio and
>these were:
>Weighting A curve frequency of 500-10,000 Hz range
> " C " " " 200-18,000 " " I think need to
>confirm the C However the C frequency is for musical instruments and the
>A for humans I think.
>Anyway the results are as follows: (It's 6,30 am Sunday morning and I
>have to go roofing before it gets too hot and I am not awake yet. The
>three studios were in full operation and three very loud bands were
>using the studios at the time of the recordings:
>Inside Studio 2 Background Noise Level A 55 db
> (No Bands Playing) Air Con 61 db
> C 54 db
> Air Con 61 db
>Outside Studio 2 Background Noise Level A 58-62 db
> (No Bands Playing) C 63-68 db
>Inside Studio 2, One Very Loud Band Playing A 105-107 db
> C 114-117 db
>Outside Studio 2, Three Very Loud Bands Playing A 62 db
> (Meter 12" from walls) C 71 db
>Outside Studio 2 Three Very Loud Bands Playing A 60-62 db
> (Meter 10' from walls) C 67-68 db
>Outside Studio 3 All Bands Playing A 65-66 db
> (Meter under the air con) C 75-78 db
>There was sound travel coming from the air con from Studio 3 from all
>the other studios. (This a problem Bruce has to rectify.)
>Outside the window Street Noise Levels A 68-71 db
> C 68-70 db
>Therefore it can be said that the straw bale walls are very effective in
>reducing sound as if you all did not know that anyway. I just have not
>been able to get any figures anywhere so here they are for what they are
>worth. It was a very scientific testing conducted with meter in hand
>and an ale in the other. (Only joking).
>I also tested some other well known noise producers whilst I was in
>Sydney. I used the A frequency.
>Inside a house that I was staying in at Sydeneham Background 51 db
> Jumbo Overhead 82 db
> Jumbo Outside 104 db
>It was intersteing to see how some Sydneysiders have to live!
>On the M5 Freeway 104-109 db
>On Parrammatta Road 83-102 db
>Thanks for listening and I will write more later when I get off the
>roof. We have started the Galston project and we set our profiles
>between Christmas and New Year.
>If anyone has some comments on these test results please let me know and
>to all of you who have written to me in the last month I am sorry that I
>have not replied but I will catch up over Christmas and New Year.
>Salaams Straw Wolf


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