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Discussion Starter · #1 ·
I just spent 15 minutes typing a post...only to have it vanish when I hit post. Damn...


so here is a short summary.


$800 of Guilford of Maine Carrera acoustically transparent fabric (at least they said so when they suggested this material...)


Just installed new triads platinums and golds...some are behind this.


8db loss on high end! The regular 701 GOM fabric is working fine, but the 1/2 of the italian villa theater that had speakers behind this Carrera fabric has no high end.


GOM insists that this is as acoustically tranparent as 701, but it isn't. They also don't publish sound specs on this fabric, as they do on the 701.


Acoustic first also confirmed that this is listed as acoustic fabric.


Oh well....hopefully this will save someone else some cash
 

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How did you find out it was an 8db loss?
 

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TonyC: if it's a no no, lots of people are in the wrong, myself included.


I guess that there is nothing in the world that is truly acoustically transparent--it's just a matter of how much attenuation you can live with. I think I remember a similar thread that noted that even FR701 is down 3 dB at 20kHz, but this was strongly debated. Maybe I have bad ears, but I can tell no difference with the fabric up or down in front of my speakers under normal movie conditions (that goes for the front left/right, side left/right and rear left/right, as the center is behind a microperf screen and that's another case altogether). I'm sure if I put a meter up, I'd see the difference.
 

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Discussion Starter · #5 ·
played a 15khz signal ...with fabric...and without. measure spl.


it is especially a big no-no to use non-acoustic transparent fabric!
 

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Discussion Starter · #6 ·
alex,


I couldn't measure or hear any difference with 701....it is the carrera line that is causing the problem.
 

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I did a simple test with the swatches we got...I spoke through one and asked my wife if she heard any difference... I ruled out the ones that blocked any voice.

The 701 seemed fine from this simple test.

Oh, you do hear some reflected sound on the "non-acoustic" ones too, plus the light doesn't penetrate them either.

Scott
 

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acaciolo,


So you are saying you measured the sound coming through the fabrics and saw no appreciable loss of high frequency with the 701 fabric, correct??


But you saw a huge loss with the non-701 fabric, right??


Thanks,


-- Cain
 

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Discussion Starter · #9 ·
Cain,


Correct. 701 = no loss


Carrera = huge loss.



Dennis Erskine is going to be coming out here in a few weeks, and we will be doing some test with his very slick RTA.


I'll post results.
 

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Quote:
Originally posted by acaciolo
$800 of Guilford of Maine Carrera acoustically transparent fabric (at least they said so when they suggested this material
Why so much? Are you covering the walls with it?
 

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I might have a suggestion.


I am covering all speakers with the 701. The more esthetic, patterned Guilford fabrics taht are not-quite-as-transparent will do the rest of the room.


The 701 fabric brochure is more detailed relative to the acoustical properties that the other Guilford 'transparent' fabrics.


Jeff
 

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Actually, I am mistaken.


The 701 and the Carrara are both listed in the acoustically transparent brochure.


However, though the fabrics are made of identical material, a listed difference is that the directionality of the fabric for the 701 is 'non-directional' and the Carrara is listed as 'directional'.


Perhaps the weave (directionality) plays havoc with the acoustic transparency or the quantification of it?


Viewing samples of both fabrics (in front of me right now), the weave of the CARRARA is much tighter than the more loosely woven 701.


Perhaps taht is also a factor. I can't see any directionality in the fabrics (as I don't know what it actually is).


P.S> My fabric bill is double yours. Crap!


Jeff
 

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Discussion Starter · #13 ·
I was using the fabric for curtains in the fake windows...to cover the surrounds....and to hide the front speakers in the stucco wall.


My plan has since changed, since I am now using the bigger triad platinums...so the speakers are going behind a microperfed "disney edition" grayhawk.


I only have to contend with the surrounds, and I am just going to switch to 701.
 

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If acoustic transparency is a really big concern you might want to look at a 70 denier Taffeta weave using either nylon or polyester.
 

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It is a Greyhawk screen with a higher gain (1.25 I believe). It is a 'beta', under evaluation, in testing, don't bug Don about it yet, stage.


(I shouldn't be speaking for Don, however.) :)
 
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