I think noise cancelling can only work at a single point in space. On the other hand, one could cancel noise at the source by broadcasting the exact opposite wave that one wishes to cancel. Not perfect, since the speaker can't be at the exact same point as the source, but close. So, in theory, engine noise could be greatly reduced.
Still, the best way to reduce engine noise is to get rid of the engine :) And not add a new source of noise :( Peri -----Original Message----- From: ev-boun...@lists.evdl.org [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart Sent: 04 July, 2013 1:01 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] silent EVs >> PS: I looked up the reference; it was Arthur C. Clarke that invented it >> in his story "Silence, Please", and not Heinlein. John Lussmyer wrote: > And you DO realize that it doesn't work, don't you? It sort-of works. But it's a lot more complicated than it seems. :-) There are real products that really do work, based on this principle. Noise cancelling headphones come to mind. It works the best on low frequency sounds, where the wavelength is long compared to the distance between the two noise sources. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
