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Linear Acoustic President Tim Carroll To Address SBE

To discuss thorny subject of managing HDTV multichannel audio levels (December 15, 2005)

Linear Acoustic, a leader in the development of systems for cost-effective contribution, distribution and transmission of multiplexed audio material, has been invited to address the Society of Broadcast Engineers on ways to control and maintain consistent audio levels during multichannel HDTV transmission. Company president Tim Carroll, an acknowledged expert in surround sound technologies, will speak to the Sacramento SBE Chapter 43 on January 24, 2006, and San Francisco SBE Chapter 40 on January 25; both are noontime lunch meetings.

"Through the use of AC-3 audio data compression technology - better known as Dolby Digital - DTV has the capability of delivering pristine quality digital audio," Carroll states, "with a potential dynamic range exceeding 100 dB on each of its 5.1 channels, equaling or surpassing the performance of a high-quality movie theater. While such a specification looks good on paper, and is referred to as 'What Hollywood has always asked for,' it is unclear whether this dynamic range is appropriate for the typical television viewer."

"Importantly," Carroll emphasizes, "the AC-3 system makes a basic assumption that audio dynamic range and program loudness are separable and can be controlled independently. This is a dramatic departure from the actions of legacy broadcast dynamic range processors installed at so many broadcast stations and networks. While there are some controls built into the so-called metadata portion of AC-3 to help tailor the audio for appropriate presentation to each listener, these parameters must be set correctly on each program for the system to function effectively. Which means that current audio producers must not only take care to make good quality audio, but also take the time to author proper audio metadata. Assuming this takes place, are there any guarantees that the metadata will make it intact all the way to the point of transmission? What if it fails or is maliciously set incorrectly?"

Carroll considers that the question of controlling dynamic range boils down to a single question: Is it all working? "In an effort to answer this question," Carrols says, "my presentations to the SBE Chapter Meetings will explore some real-world scenarios and their measured results. I will present actual examples of successes and failures, and the root cause of each will be described along with technical details of several add-on solutions designed to help broadcasters and consumers. And I will also take a few minutes to explore surround for digital radio and discuss some of the technical challenges emerging in this new market."

Chair of SBE Chapter 40 San Francisco is Arthur Lebermann from KGO/KFSO/KMKY; Jack Davis from KTXL-40 chairs SBE Chapter 43 Sacramento.

Founded in 1964 The Society of Broadcast Engineers has more than 5,000 members in 100 local chapters. SBE provides a forum for the exchange of ideas and the sharing of information to help its members keep pace with the rapidly changing industry. Members come from commercial and non-commercial radio and TV stations and cable facilities; a growing segment of members are consultants and contractors. Field and sales engineers and engineers from recording studios, schools, production houses, CCTV, corporate audio-visual departments and other facilities are also members of SBE. Though chartered by the national organization, SBE chapters operate as independent sub-groups, electing their own officers and planning their own monthly programs.

Information on the Jan 24 Sacramento SBE Chapter 43 meeting can be found at Information on the Jan 25 San Francisco SBE Chapter 40 meeting can be found at:

Current Linear Acoustic products include:
* StreamStacker Multichannel Audio Distribution System, which comprises the Model LA-5421 StreamStacker Audio Bitstream Multiplexer and Model LA-5124 StreamStacker De-Multiplexer/AC-3 Splicer.
* Model LA-5124 with AutoNorm Automatic Dialog Normalization System.
* OCTiMAX 5.1 Digital Television Audio Processor.
* UpMAX 2251 5.1 Channel Surround-Field Synthesizer.
* AEROMAX-HDFM Multichannel Radio Processor.

About Linear Acoustic
Linear Acoustic has been involved in projects with Dolby Laboratories, Sirius Satellite Radio, Microsoft, all major terrestrial networks, multiple local stations, HBO, Viacom (Showtime, MTV, etc.), Disney, Miramax, Sony Studios, and others. It is also actively involved in the ATSC, the NRSC and other industry organizations, as well as being members of the AES, IEEE and a sustaining member of the Society of Motion Picture and Television Engineers.

Linear Acoustic, Inc., 354 North Prince Street, Lancaster, PA 17603, USA |


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Related Keywords:Linear Acoustic, SBE, multichannel audio, Society of Broadcast Engineers, surround sound,


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