Audio News for February 24, 2007

New Technology For Surround Sound Using Existing Stereo Channels – THX Ltd. and Neural Audio Corporation announced at the recent CES 2007 in Las Vegas that they are working together to develop the latest generation of Neural Surround products for consumer electronics, broadcasters, video gamers and various new distribution channels.  The technology is a real breakthru that moves well beyond previous efforts such as Pro Logic IIx and Circle Surround, in its ability to originate true 5.1 or 7.1-channel sound, encoding it using a process that is transparent to stereo-only listeners, pipe it thru existing stereo channels – even on the Internet – and decoding it with Neural-enabled home tuners and receivers to full blown surround sound. The encoded signals can be broadcast or stored on standard CDs.

An HD Radio station in Colorado is already broadcasting programming using Neural Surround, and XM Satellite Radio has for some time been offering two channels of HD Surround to listeners across North America using the process. Aside from existing surround sound recordings in different formats, broadcasters can use the THX-Neural Surround solution to encode 5.1 content during a live mix or post session and then transmit it in a two-channel format to all audiences. A THX spokesman observed “Unlike traditional matrix-encoded technologies, the THX-Neural solution enables sound designers and mixers to better pinpoint sound effects, ambient sound and other audio elements in the surround field, providing for more immersive entertainment experiences…” As expected, the technology is especially attractive to video game producers since it creates more interactive 360-degree soundtracks that pull gamers closer to the action. Decoders will first appear in AV receivers from Sony, Pioneer, Onkyo and Yamaha.

Consumer Testing of AM Broadcast Transmission Bandwidth – Discussion of AM radio would seem beside the point for this publication, but an interesting (though depressing) recent survey by the National Radio Systems Committee (NRSC) uncovered some odd facts about audio performance of typical AM radios. An AM Study Task Group of the organization conducted a subjective consumer evaluation survey of audio from three prototypical receivers plus a variety of consumer analog AM sets, including aftermarket car radios, shelf mini-systems, boom boxes and portables. The results showed that for speech – which constitutes the majority of AM content today – listeners preferred lower bandwidths (5 and 7 kHz) to higher whenever there was interference and noise from adjacent channels or poor reception. It was found that the preferences changed depending on the type of content – noise was found more annoying with speech than with music, sports or commercials. Consumers tolerated a more constrained bandwidth when the signal had reduced noise. Many AM broadcasters have already reduced the bandwidth of their signals from the 10 kHz specified by the NRSC down to 5 to 6 kHz.  And nearly all AM radios today are greatly reduced in bandwidth and sensitivity compared to the high quality mono audio that was once the standard for both broadcasters and radios in the 1940s.