Talk:Anechoic chamber

confused acoustic vs rf
Dear Concerned,

I like this article a lot, but I am also getting quite confused halfway through it, as it seems to jump back and forth between acoustic and RF chambers. It woudl help, I think, if they could be basically just split into two different sections completely. They could refer to the other, where there are similarities, but overall, the two different ppl reading this are gonna be people interested in sound recording, and people interested in RF testing... and so the different sections should focus on addressing those two aduiences separately imho.


 * I've rewritten things a little bit to hopefully clarify Richard☺Decal (talk) 03:48, 31 March 2017 (UTC)

etc
As an aviation enthusiast I've heard of anechoic chambers being used for radar signature measurement, where the echos absorbed are radar echos, not sound echos. Anechoic chambers for EM radiation should be mentioned in addition to ones meant for audio purposes.

I'll try to do a significant revision and addition to incorporate this. mnemonic 10:49, 2004 Jun 21 (UTC)

Should the words "dampening" and "dampened" be used? Doesn't that mean the panels are making something wet? ;)

Perhaps "damping" and "damped" should be used.

More here:

http://en.wikipedia.org/wiki/Dampening

Acoustic and RF (electromagnetic) anechoic chambers
I have added several paragraphs about RF anechoic chambers as opposed to acoustic ones and I have not as yet deleted anything. I think it improves the article but it could do with a tidy up, or perhaps it might be worth splitting it into the two different types. If nobody else does I'll get back to it in a few weeks.

I think some clarification is needed about the acoustic and RF wavelengths. It is true that a typical audio frequency of 500Hz acoustic wavelength (0.7 m) is very different from 500 Hz electromagnetic (600 km) but I don't think many RF tests are done as low as 500 Hz. But 0.7 m RF wavelength I make about 454 MHz. Many tests are done around these UHF frequencies. ChrisAngove 17:43, 10 November 2006 (UTC)

Suggested Improvements
Picture of the interior of an RF anechoic chamber if possible showing something being tested. References to the particular international standards (a) that chambers are built to and (b) that are typically tested for in the chambers. A picture or two showing the shell construction ie. the screened room for the RF and the 'metre thick cement' or similar for the acoustic one. ChrisAngove 17:39, 18 November 2006 (UTC)

Acoustic Testing of Satellite Components
Does anybody know anything about the very high level acoustic noise testing that used to be done on components to go into space? I believe it may have been to similate launch conditions. Do they still do it or has it been superceeded? The levels would need a heavy duty chamber i think. ChrisAngove 17:39, 18 November 2006 (UTC)

Acoustic Anechoic chamber?
Why is all the information about acoustic anechoic chambers here in the discussion page rather than in the actual article? —The preceding unsigned comment was added by 67.64.252.71 (talk) 20:41, 13 May 2007 (UTC).

Advertisement?
Reference 1 to the TDK RF solutions page seems to lead to a commercial website providing absorption solutions, without really benefiting the article.46.144.116.121 (talk) 09:47, 6 August 2014 (UTC)

semi or hemi anechoic
Hi,

I think it would be of interest of many people to add a chapter about semi and hemi anechoic chambers with regard to the different measurement possibilities. —Preceding unsigned comment added by 82.210.249.81 (talk) 09:56, 6 December 2007 (UTC)

Quick reply to this - Semi-anechoic is used to describe RF chambers. I think hemi describes acoustic, but I have no experience with those. I have never heard hemi used in relation to RF chambers - EMC enginer —Preceding unsigned comment added by 66.41.160.226 (talk) 01:25, 14 February 2008 (UTC)

partly wrong
the whole RAM-section contained factual errors, and had no citations or sources: (ferrite plates vs. pyramid shaped is just completely wrong since i know that the ferrite plates are less effective at HIGHER frequencies) source: I found a ferrite plate damping curve, but there might be other/better sources.

There might be more factual errors, since large parts of this article remain unverified.

—Preceding unsigned comment added by 194.116.159.61 (talk) 13:13, 21 January 2008 (UTC)

Caves?
Mention if caves are good s, at least electronically. Jidanni (talk) 02:26, 22 February 2009 (UTC)

Acoustic anechoic chambers
Is this right: "In general, the interior of an anechoic chamber is very quiet, with typical noise levels in the 10-20 dBA range." The University of Salford has a semi-anechoic chamber with only 3.8dba background noise, so this seems hard to believe. Also, the University of Salford claims an anechoic chamber with a -12.4dBA background noise level, so perhaps this Guinness record needs updating. I don't really know anything about this topic, but a quick google search yielded these. Anybody know more about this? NeverWorker (Drop me a line) 03:27, 29 July 2009 (UTC)


 * The "in general" phrase is correct. Few chambers go lower than 10dBA. The dBA measurement is relatively insensitive to low frequencies, so a low dBA number might be hiding a degree of low frequency rumble. 0dBA is 20 micropascals, or the lowest level a human can hear. Going lower than zero dBA is a very rare achievement. Binksternet (talk) 04:01, 29 July 2009 (UTC)


 * A thing I think is missing from the article, is the effect is has on humans. Not only is it quiet; it is so quiet that you can hear the blood run in your veins. The first time I experienced this was in an anechoic sound studio in NRK Marienlyst in Norway. It made me feel quite disconcerted, and some of the women freaked out and got claustrophobia. Also, sounds from others were dampened quite a bit since no sound was allowed to echo, so you felt like you had to yell to be heard even if somebody was right next to you. 80.203.35.234 (talk) 02:21, 7 April 2013 (UTC)

Does this have the frequency culprit reversed???
The sentence: "Such risks are from RF or non-ionizing radiation and not from the higher energy ionizing radiation." DOES THAT have the culprit reversed? 68.121.32.86 (talk) 23:03, 29 June 2013 (UTC)
 * It is correct. Risks from high levels of non-ionizing RF include heating (burning or cooking) and electric shocks. It can also affect objects carried such as watches, spectacle frames and heart pacemakers. &mdash; Cheers, Steelpillow (Talk) 12:23, 25 October 2015 (UTC)

Effect on people remaining within room
No mention of how it produces an unsettling effect and the longest anyone's stayed in one is 45 minutes? Really? — Preceding unsigned comment added by 162.157.42.210 (talk) 05:20, 26 May 2014 (UTC)
 * Me thinks what the article so far has to say about that is quote off: "Anecdotally, some humans may not like such quietness and can become disoriented." It is not anecdotally that it is unsettling. Though I found no medical or otherwise scientific article or research about that per se, it is mentioned in this article: http://www.odditycentral.com/news/worlds-quietest-place-lets-you-hear-your-internal-organs.html : "as it turns out people can’t stand to be in the world’s quietest place for too long. The longest a person has lasted in there is 45 minutes. [...] The room gets so silent that you can actually hear your internal organs at work. And after a while, the hallucinations begin. [...] The founder and president of Orfield Labs, Steven Orfield says that people are challenged to sit in the chamber with all the lights out. There was this one reporter who managed to stay in there for 45 minutes. Mr. Orfield himself can do it for 30 minutes, in spite of his mechanical heart valve that becomes very loud inside the room. «When it’s quiet, ears will adapt,» he says. «The quieter the room, the more things you hear. You’ll hear your heart beating; sometimes you can hear your lungs, hear your stomach gurgling loudly. In the anechoic chamber, you become the sound.» The experience is so disorienting that it could drive a person mad. In fact, it is imperative that people sit down. Standing up and walking around is simply impossible. Because we orient ourselves through the sounds we hear when we walk, there are no cues to go by inside the chamber. «You take away the perceptual cues that allow you to balance and maneuver. If you’re in there for half an hour, you have to be in a chair,» Mr. Orfield says." (emphasis by me) And this is about the -9dB room, not the -21dB room.
 * So, not being able to stand for a mere 30 minutes, even suggesting people sit down as quick as possible (" it is imperative that people sit down. Standing up and walking around is simply impossible. Because we orient ourselves through the sounds we hear when we walk") sounds so much more factual than just what the article so far says, as quoted above. ("Anecdotally, some humans may not like such quietness and can become disoriented"). So, while I only found this article on that, and even less info in http://www.mprnews.org/story/2012/04/03/daily-circuit-quiet-room it still, to me, is enough factual data to remove the above quote and insert more about the factual disorienting experience, especially in the dark, also when combined with the everyday action of standing and walking around. Dietmar Lettau (talk) 17:45, 23 August 2016 (UTC)

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