it's quite hard to know indeed. I only found this on the web :
http://www.ogi.edu/satacad/ase/mentor/s ... ve%20Noise
(or http://www.ogi.edu/satacad/ase/mentor/s ... cspds.html and look for "Active Noise Cancellation Project" . )
<font size=-1>[ This Message was edited by: spacef on 2002-05-31 14:43 ]</font>
Another PC noise trick
actually a search for
Active Noise Cancellation
with the following engine
http://www.google.fr/
and began to find useful stuff.
(we're pretty far from the topic though.
sorry for the noize
Active Noise Cancellation
with the following engine
http://www.google.fr/
and began to find useful stuff.
(we're pretty far from the topic though.
sorry for the noize

i couldn't let this link unoticed
http://www.measure.demon.co.uk/Acoustic ... e/anc.html
http://www.measure.demon.co.uk/Acoustic ... e/anc.html
http://www.nct-active.com/technology.htm
http://w2.nasatech.com/ITB/Fr/14_430.html
http://www.innovative-dsp.com/products/ancapp.htm
http://www.mrivideo.com/temp/upcoming/activenoise.html
http://www.baddogaviation.com/upgrade.htm
http://www.voicerecognition.com/product ... a/faq.html
http://www.non.com/news.answers/active- ... l-faq.html
http://www.signalsystemscorp.com/anc_organizations.html
http://www.avweb.com/sponsors/litspeed/anr101.html
http://doctord.dyndns.org:8000/Pubs/POTENT.html
http://www.compandent.com/

http://w2.nasatech.com/ITB/Fr/14_430.html
http://www.innovative-dsp.com/products/ancapp.htm
http://www.mrivideo.com/temp/upcoming/activenoise.html
http://www.baddogaviation.com/upgrade.htm
http://www.voicerecognition.com/product ... a/faq.html
http://www.non.com/news.answers/active- ... l-faq.html
http://www.signalsystemscorp.com/anc_organizations.html
http://www.avweb.com/sponsors/litspeed/anr101.html
http://doctord.dyndns.org:8000/Pubs/POTENT.html
http://www.compandent.com/

Actually as far back as the late 80's and early 90's I was reading articles in Car & Driver and other automobile magazines on the phase cancellation systems that were being developed at the time by Cadillac, BMW, Mercedez, Lexus etc. If I remember correctly they use the technology both for audible road noise/vibration cancellation through speakers located in the lower body panels in the car, and also on suspension parts to act against vibration from the road.