High-Tech Window Cling is Like a Volume Knob for Real Life • Hacker News Board

Post by msandford » Tue, Oct 29, 2013, 10:13 PM UTC

dustcoin wrote: post #22

msandford wrote: post #20

Earlier quoted context omitted.

I've done quite a bit of signal processing in my day. Audio, image/computer vision, radio comms, etc. This product strikes me as not terribly honest for a few reasons: Geometry The mic/speaker assembly are in the middle of the window but the window has substantial size relative to the dimensions of the room and the distance the listener is from the device. What this means is that you have a multipath problem; the ori…

The mic/speaker assembly are in the middle of the window but the window has substantial size relative to the dimensions of the room and the distance the listener is from the device. For what it's worth, the pictures in the article show a series of rings around the device that significantly increase its surface area, a component that is not present on the device in the video.

Yeah I'm not optimistic about those. They're clearly too small to be electromagnetic drivers (think magnets and coils) so best-case they're active piezo devices that are epoxied on (need to have a good bond) turning the whole window into a radiative speaker. Sadly those are limited to high frequency sound only (several kHz and up) so they wouldn't do much good for anything other than perhaps the bottle noise.

http://en.wikipedia.org/wiki/Loudspeaker#Piezoelectric_speak...