Leibson's Law: It takes 10 years for any disruptive technology to become pervasive in the design community. This blog is about the disruptive technologies that either have or will win over electronic engineers, some that won't, and why. Written by Steve Leibson, Tensilica's Technology Evangelist. See my history site at www.hp9825.com. You can email me by taking the first letter of my first name, appending that to my last name, then the magic email symbol, followed by the name of the company I work for, and then a dot followed by com.
Jan 9 2008 3:14PM | Permalink | Email this | Comments (2) |
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My last visit before leaving the CES 2008 show was with a British company named airSOUND. (You’ve gotta love these silly corporate-centric capitalizations.) Founder Ted Fletcher has invented a way for two co-located speakers in one enclosure to produce a stereo-effect sound field. The secret is the way the speakers are fed and the way they’re positioned in the box. A forward-firing speaker emits left-plus-right sound. A second speaker, trapped in a sealed port in the box, emits left-minus-right sound from a port in the left side of the box.

Thus the composite signal emitted to the listener’s left is simply “left” (L+R+L-R) = 2L (effectively L). The acoustic signal emitted out of the right-hand enclosure port is 180 degrees out of phase with the left-port signal (as generated by the back of the (L-R) speaker), so it is –(L-R) or R-L. Thus the composite signal heard on the right side of the enclosure is (L+R) + (R-L) = 2R. Ingenious.
It sounds good as well. The need for only one enclosure to produce a stereo sound field simplifies many product designs, so if you need something like that, look into airSOUND.
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