> With its concentric broadband antenna rings, it harvests the energy of electromagnetic noise from Wi-Fi, and similar signals and this way also reduces the level of e-smog pollution in your environment.
facepalm. This is nonsense.
I always thought the only way of doing this would be to have detached microphones positioned between the speaker and the target noise so the system has enough time to compute the inverse of the incoming waves and send them out with enough space to cancel in the correct phase.
Really, fellas? I don't mind a discussion on how it could possibly be done, but where's your rudimental critical thinking? Even reddit had a better discussion [1].
[1] http://www.reddit.com/r/gadgets/comments/1pdfb0/volume_knob_...
Of course, there's one question the article didn't address: what proportion of sound is actually transmitted through window panes? One would expect that a whole lot of low-frequency sounds (traffic) would come through the walls too.
To see why this is useful, imagine a song you wanted to listen to that was recorded with a low-pitch hum in the background because the microphone running next to a power cable and picked up the 60 Hz signal. Removing this unwanted tone by looking at the value of the song in time is really hard because the 60 Hz signal is mixed up with the rest of the song. However, when transformed into the frequency domain, the 60 Hz hum is very easy to spot and remove. When you transform the signal back into the time-domain (so you can listen to it), the 60 Hz will still be gone.
This process can be done automatically with computers using a technique called the Fast Fourier Transform. This is the basis of many techniques in the field of Digital Signal Processing (DSP) which is the theory behind most of the communication breakthroughs of the last 40 years. I should note that many naive approaches to this problem (like the approach in my example) don't work particularly well, so as in any problem domain, there are important but subtle performance trade-offs to consider.
Years ago I wanted to splice a noise canceling headphone into one of these devices and make the windows noise canceling. Would that even be feasible?
I just don't believe this concept could work the way the video demonstrates it. Nice interface though... but that's kind of the easy part.
