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Re: [Phys-L] decibels



Some decades ago I visited the Ontario Science Centre in Toronto and enjoyed walking through an anechoic tunnel.
The lack of sound seemed to exert a PRESSURE on the ears! Very Strange experience.


On May 1, 2019, at 12:49 PM, Scott Orshan via Phys-l <phys-l@mail.phys-l.org> wrote:

Many years ago, I had the opportunity to visit the Bell Labs' anechoic chamber a few times. We used to go back there when we were in the building for lectures.
All six surfaces of the rectangular room were covered with absorptive wedges, so the "floor" is a taut metal wire grid. You are standing suspended above the floor, on this bouncy grid.
https://www.pbs.org/wgbh/nova/article/retroscience-in-the-sound-of-silence/
https://www.musictech.net/wp-content/uploads/2018/03/Beatie-Wolfe-in-the-anechoic-chamber-at-Bell-Labs-min-696x464.png


Message: 1
Date: Tue, 30 Apr 2019 11:23:56 -0500
From: brian whatcott <betwys1@sbcglobal.net>
To: phys-l@mail.phys-l.org
Subject: Re: [Phys-L] decibels
Message-ID: <a0a89d62-bd34-c36f-501c-d44e0a428f94@sbcglobal.net>
Content-Type: text/plain; charset=utf-8; format=flowed

On 4/29/2019 6:20 PM, Anthony Lapinski wrote:
A student sent me this short article about the world's quietest room:

www.smithsonianmag.com/smart-news/earths-quietest-place-will-drive-you-crazy-in-45-minutes-180948160/

Anyone ever been in a room like this?

And what do negative decibels mean? The "threshhold of hearing" (10^-12 W/m2)
corresponds to 0 dB. So a sound quieter than this (say, - 20 dB) has an
even lower intensity (10^-14 W/m2)? Is there a lower limit?

How does this work with volume control knobs on stereo systems?


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