A Linear Acoustic OCTiMAX 5.1 Digital Television Audio Processor is being used on-air at KGTV-HD Channel 10, the San Diego-based ABC affiliate, to provide multichannel audio from two-channel material. "Our audience reacted negatively to changes between two-channel and 5.1 material as we changed signal sources," says Ron Eden, Chief Engineer. "OCTiMAX is very easy to use. The 5.1-channel output sounds extremely realistic."
"HDTV viewers expect 5.1-channel sound all of the time," Eden considers. "When a station mixes stereo audio with 5.1-channel surround sound it's a major let down for the audience. We pass all of our two-channel material through the OCTiMAX 5.1 Processor. Right out of the box the system has worked flawlessly. It took less that five minutes to set up; we have had to make only minor adjustments since we put the unit into service."
"We are the only commercial station in our market that transmits HD in 5.1 all the time," says Eden. "That capability gives us a significant advantage over the competition."
The OCTiMAX 5.1 Digital Television Audio Processor combines multichannel, multiband dynamic processing with audio metadata functionality and local audio insertion capability. An integral UpMax 5.1 Channel Surround-Field Synthesizer produces 5.1-channel audio from a standard two-channel mix, with full control of center width and surround depth.
"The Linear Acoustic OCTiMAX 5.1 produces a clean, consistent and appropriately dynamic audio signal that is perfect for Dolby Digital AC-3, MPEG, or Windows Media encoding and transmission," considers Linear Acoustic president and founder, Tim Carroll. "Our Auto Voiceover(tm) feature allows straightforward insertion of voiceover audio, while UpMax enables local and network audio to be transformed into excellent quality 5.1 audio. The resulting signal is fully mono, stereo and matrix surround compatible."
OCTiMAX 5.1 also generates an Lt-Rt-compatible stereo downmix of the main program that can be used to feed legacy two-channel systems. The processing structures support eight mono programs, a 5.1 + 2 channel program and any format in between. "The proprietary processing structure combines a two-band AGC with five bands of compression, look-ahead and peak limiting for each channel of audio," Carroll adds. Advanced multiband source noise reduction is available to improve the sound of legacy films and older television programs.
Linear Acoustic also offers a companion unit, UpMAX 2251 5.1 Channel Surround-Field Synthesizer, which produces 5.1-channel audio from a standard two-channel mix, with full control of center width and surround depth; in essence it is equivalent to the OCTiMAX 5.1 Digital Television Audio Processor, but without the dynamic range processing. As such, it is more applicable to production environments where the 5.1-channel output will be incorporated with other program sources prior to final broadcast processing.
