Talk:Active noise control

message: It is used as a citation without any real citation.  — Preceding unsigned comment added by 78.162.232.188 (talk) 14:29, 25 January 2020 (UTC)
thread_title:  Reference 2 needs a citation itself 

message: I would like to know about the companies who can supply active noise cancellation ear defenders and also DSP based active noise controller (with adaptive algorithm or LMS- & FXLMS algorithm.
Thanks for your valuable reply.
:Google would be the obvious place to start.
:By the way, you can "sign" your talk postings by including four tildes (~~~~) after your post. When you press "Save page", these will be converted into your username or IP address in a handy, Wikilinked format. A timestamp for your post will also be included.
:Atlant 14:03, 17 February 2006 (UTC)
thread_title:  Active Noise Controller 

message: I've removed this recently-added text from the article. To me, the description farther up in this talk page is more accurate. This newer description doesn't include the simple nearly-instantaneous, band-limited feedback mechanism that is commonly used in ANC headphones.
:Several different types of noise cancellation are possible. First is feedback, where a periodic signal is processed to produce a periodic signal of the opposite phase at a certain location of space, usually near an error microphone. This requires the noise signal to be periodic. Secondly is the feedfoward system, in which noise is recorded along a path between the noise and cancellation actuator(s). In a causal system, noise is recorded close to the source such that sound of an opposite phase can intercept it along a path. This system does not require the signal to be periodic.
:Atlant 21:35, 20 March 2006 (UTC)
replies: text:  Unfortunately this description is much better than the one in the article. It has the virtue of being more complete. The article concentrates overmuch on FFT based, periodic, type cancellation. Real world cancellation of impact type noise has been demonstrated, and the sstem I used was based on time history filtering, not FFTs. Greglocock 10:18, 22 February 2007 (UTC)
thread_title:  A removed description 

message: I'm curious as to whether it is (at least theoreticaly) possible to cancel the light rays of the visible spectrum through polarity reversal and/or 180° phase shift.
Could it be possible to generate a frequency that effectively cancels the phases of the ROYGBIV light rays?  
And if so, then... 1.) would this create a state of total darkness?, or rather some other visible sensation?  And... 2.) could such a high frequency possibly be generated with extant radio and multimedia hardware?
[It's a big question, but also one that has been nagging at me for quite some time :P ]
Pine 16:20, 18 July 2007 (UTC)
replies: text: with the current technology it would be possible to accuratly control the phase of a very short laser puls (femtoseconds long) at a chosen frequency using high-resolution spectral phase shapers. Using two of these setups in a controlled environement would cause cancelation of the lightpuls. But to cancel a short controlled puls is something entirely different than to cancel a diffuse lightsource with a wide spectrum. Creating the right frequencies could be done using liquid cristals (LCD screens), but since the area in which a random lightsource would be coherent with the generated cancelation source is only several nanometers at max, the cancelation area would also be several nanometers, shorter than the wavelenght of light (800nm) and therefor does only alter the light, not cancel it. (i'm no optical scientist; imperfection at complete certainty)  Frodo Muijzer (talk) 10:37, 23 October 2008 (UTC)
thread_title:  Phase Cancellation of Visible Light Rays [?] 

message: I can't see any support for the idea that sound waves have "polarity" at all—rather (mainly)) electrical signals do (as do light waves). It appears that one (but not the only) way to generate a phase-reversed wave is to invert the polarity of a signal simultaneously. Are there any references to the polarity of sound waves in the first place? Bongomatic 05:36, 3 December 2009 (UTC)
thread_title:  Polarity v. phase again 

message: I plan on adding more theory on the physics behind Active Noise Control. Additionally I think providing more information from reliable white paper research will enhance the article.
Bartscrc-NJITWILL (talk) 01:45, 10 November 2011 (UTC)
thread_title:  Theory and References 

message: Dumb post - Has this been used/tried for trumpets. Even the best trumpet practice mutes don't sound that good/real ( at least to me ) and the back pressure is distressing ( at least to me ). If a device could be attached... to a trumpet bell could it kill the sound in the room while I blasted away and got a more real but reduced sound in a headphone. 
24.128.186.53 (talk) 00:19, 12 February 2015 (UTC)
replies: text: I'd say it is possible to reduce the average sound level, but I doubt you'd easily quieten the initial attack phase. Not a dumb question at all actually. Greglocock (talk) 02:22, 12 February 2015 (UTC)

text: Initial attack phase? Someone ought to tell Chris Goldscheider. But I guess it's a bit late now. Martinevans123 (talk) 15:59, 30 April 2018 (UTC)
thread_title: Trumpets

message: I have seen no evidence at all that this uses ANC, which would be tricky in any case. The only technical description suggests they are using masking, ie drowning out the boos with applause. Greglocock (talk) 03:21, 12 July 2015 (UTC)
thread_title:  Eurovision anti-booing technology 

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*Added archive https://web.archive.org/web/20120426050529/http://www.medialab.ch/archiv/pdf_studien_diplomarbeiten/da05/da2005-104_ActiveNoiseControl.pdf to http://www.medialab.ch/archiv/pdf_studien_diplomarbeiten/da05/da2005-104_ActiveNoiseControl.pdf
*Added archive https://web.archive.org/web/20070509115208/http://www.acoustics.org:80/press/147th/active-noise.htm to http://www.acoustics.org/press/147th/active-noise.htm
*Added archive https://web.archive.org/web/20120219205955/http://www.bose.co.uk/GB/en/learning-centre/featured-stories/escape-the-noise/ to http://www.bose.co.uk/GB/en/learning-centre/featured-stories/escape-the-noise/
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thread_title:  External links modified 

message: I realise without refs this cannot go into the main article, but the first time I saw an accelerometer based feedforward ANC to cancel road noise was in the late 80s at Lotus. It was fitted to a large Audi and a Porsche. I don't know if either company took it to production. Hence Hyundai's claim of a 'first' is rather inaccurate. Greglocock (talk) 07:29, 20 February 2020 (UTC)
thread_title:  Hyundai RANC 

message: Need your thoughts on whether this should be a separate topic from Noise cancellation or Adaptive filtering. It appears to be someone's research material. Please help discuss at Draft:Adaptive noise cancelling#Notability for this. AngusW🐶🐶F (bark • sniff) 18:52, 21 January 2023 (UTC)
thread_title:  Adaptive noise cancellation