Audio Engineering Society

Chicago Section

Meeting Review, May 30th 2002

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5/30/02 Meeting Highlights
by Bob Zurek

Evolution of High Resolution Digital Audio in an Era of Multichannel Surround

On May 30th Gene Radzik of Dolby Laboratories gave a presentation entitled “Evolution of High Resolution Digital Audio in an Era of Multichannel Surround.” Mr. Radzik began his presentation by giving a brief overview of the 125 year history of recording and the evolution of multichannel audio. He highlighted dates such as the invention of stereo audio in 1931, and the attempts at four channel audio between 1954 and 1976. Mr. Radzik noted that we are currently changing from a two-channel world to a multichannel world. He talked about the advent of the DVD format in 1993 and 1994, and traced the origin of DVD Audio to the 1996 international steering committee recommendation for a new audio format. He discussed the DVD audio disk specifications and compatibility, and compared the DVD audio format to the Compact Disk. Mr. Radzik explained that the DVD Audio disk’s 4.7 GB of storage space is able to hold up to 89 minutes of six channel 96kHz 24 bit audio, 125 minutes of 2 channel 192kHz 24 bit audio, or 230 minutes of two channel 96kHz program material. In order to achieve these storage capacities, the DVD audio disk uses Meridian Lossless Packing. MLP provides approximately a 2:1 compression ratio of the program material. In addition to this compression, MLP allows additional metadata to be included on the disk including down mixing information all the way to mono. The presentation then turned to the Dolby Digital system which among other things allows the normalization of dialog as well as consumer controlled dynamic range control. Mr. Radzik’s presentation was followed by a question and answer session and a demonstration of a typical setup for a home digital multichannel system.