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Audio News for September 14, 2012

Princeton Professor Says Two-Speaker Surround Possible; Dolby Digital Plus Delivers Audio for UltraViolet

Published on September 14, 2012

Princeton Professor Says Two-Speaker Surround Possible – There have been many different technologies that claim to offer surround sound from only two speakers. Among them Harman’s VMAx, various SRS Labs software, Carver Sonic Holography, Lexicon’s crosstalk-canceling circuit, Polk’s former extra canceling drivers, and various proprietary gimmicks included by manufacturers in their TVs and other electronic gear. So it’s not new, but a Professor Choueiri at Princeton has a technology he calls DynaSonix which factors in the dimensions of the human head, shoulders, etc. (called HRTFs) to ensure a stereo listening experience that is free of the crosstalk of the left speaker sounds getting to the right ear and vice versa. The ears don’t have to sort thru sound waves that appear at both ears at different times, frequencies and levels.

Most of this work is based on binaural research. Binaural involves omnidirectional mics in the two ears of a dummy head and playback usually thru stereo headphones to keep the left and right channels totally separated at the ears. Binaural is able to provide total 360-degree spatial hearing which no speaker-based surround system can achieve. Having the two speakers closer together improves many of these approaches, and Choueiri says that DynaSonix, if properly employed, could effectively achieve surround sound performance from a simple two-channel soundbar. From my own listening comparisons I would say “good luck.” Even the most effective of the two-channel speaker technologies have the disadvantage of requiring a very narrow “sweet spot”—moving away from which destroys the effect. The only truly effective technology I have heard is the Smyth Research Realiser A8 processor, which requires headphones, and can accurately replicate a multi-channel listening experience (but does not have the proper test tone setup for binaural sources).

Dolby Digital Plus Delivers Audio for UltraViolet – Devices and services supporting hi-def entertainment are growing, and the Dolby Digital Plus codec will now be bringing high-quality audio to the UltraViolet platform, allowing consumers to create personal digital entertainment collections they can access at home or on the go across multiple devices. UltraViolet’s Digital Entertainment Content Ecosystem (DECE) uses Dolby Digital Plus-encoded CFF (Common File Format) files to make it easy for consumers to move or copy downloaded files directly across devices or applications without needing additional downloads or bandwidth. Several different providers are working to deliver high-quality audio for the UltraViolet initiative.

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