Re: double-wall sound proof booth attenuation

[Daniel Shub <Daniel.Shub@xxxxxxxxxxxxxxxx>]

The National Biomedical Research Unit in Hearing had two double walled IAC booths installed last year. IAC made onsite measurements that showed at least 80 dB of attenuation. The documentation with the  measurements say "the isolation values above 500 Hz are affected by the noise level of the source, is it not great enough." I interpret that gibberish to mean that the maximum level they could generate outside the booth did not result in a measureable increase in the level inside the booth.



> -----Original Message-----
> From: AUDITORY - Research in Auditory Perception
> [mailto:AUDITORY@xxxxxxxxxxxxxxx] On Behalf Of LAVANDIER mathieu
> Sent: Friday, March 05, 2010 4:44 PM
> To: AUDITORY@xxxxxxxxxxxxxxx
> Subject: [AUDITORY] double-wall sound proof booth attenuation
> 
> Dear list,
> 
> 
> 
> Would anyone have measured the attenuation characteristics of a double-
> wall sound proof booth once the booth is installed on site, compared to
> the characteristics announced by the manufacturer?
> 
> 
> 
> I'm having a booth built, and after several installation attempts (by
> the manufacturer), I still don't get what was announced.  Basically,
> they announce an attenuation over 90 dB above 1 kHz (which is huge),
> I'm getting 70 dB (which is quite good, but still 20 dB less than what
> I'm paying for...), and the manufacturer says: "that's fine, that's what
> we normally get for measurement on site".
> 
> The reference measurement giving over 90 dB is supposed to be done in a
> reverberant room (so, same sound level all around the booth during the
> measurement). The room where my booth is installed might not be as
> reverberant; but I'm doing the measurement with the microphone between
> the sound source and the booth, so on the worse side of the booth. So I
> anticipate that, if my room was perfectly reverberant, I would get
> equal or smaller performances...
> 
> 
> 
> I would like to know if I'm getting what others are getting or if I
> should keep on complaining. Actually, very soon the manufacturer will
> not have any proposition for improvement (they told me already) so I
> have to decide if I keep the booth, or if they take it away and I'm
> looking for somebody else to build me a better one... (I haven't tell the
> manufacturer name, but it might be difficult to find a better known
> company in the field...)
> 
> 
> 
> Thanks in advance for your advice,
> 
> 
> 
> Mat
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> -----------------------------------------------------------------------
> ------------------------
> 
> Mathieu Lavandier
> Université de Lyon, Ecole Nationale des Travaux Publics de l'Etat
> (ENTPE)
> Département Génie Civil et Bâtiment (DGCB), Unité CNRS 1652
> 
> Rue M. Audin, 69518 Vaulx-en-Velin Cedex, FRANCE
> Tél : +33 (0)4 72 04 70 30
> Fax : +33 (0)4 72 04 70 41
> 
> 

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