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3D dimension Audio adding A worth Another way of adding a new dimension – and therefore more realism - to audio is Ambisonics. First developed in the 1970s, Ambisonics introduces ‘height’ to sound, providing a layer that 5.1 surround sound cannot. BBC Research and Development describes it thus: “Ambisonics captures audio from three perpendicular figure of eight microphones all positioned at the same point in space. When combined with an omnidirectional microphone these four signals are know as B-format. This signal represents the three-dimensional soundfield.”  To play this back this you’d expect to need more speakers but that’s the beauty of Ambisonics. It actually uses four signals that are interpreted by the receiver to give us any number of loudspeaker signals. The major benefit of Ambisonics is that, unlike surround sound (or Transaural processing), speaker positioning is not essential. So, from a broadcast perspective, one common set of signals could be sent to all viewers who would then be able to decode it to suit their listening environment, regardless of how their surround sound system is set-up. Unfortunately, mass adoption of Ambisonics is some way off, not least because sound localization using four streams is not considered to be quite good enough yet and to improve it would currently require more channels, which kind of defeats the point. More work required. For a market-ready 3D audio perhaps we should look to Dolby Atmos. A cinema technology at present, this new format is being used on Pixar’s latest animated movie, Brave, which opens next month. It is said to envelope the listener, giving the illusion that there is an infinite number of channels all around and above them. According to the marketing blurb Dolby Atmos enables “adaptive rendering” to make sure that the playback experience is as close as possible to the creator’s original vision regardless of where the speakers are. And we’re not just talking about speakers on the ceiling and behind the screen. Dolby Atmos is said to be able to transmit as many as 128 channels and render anything from 5.1 surround to 64 discrete speaker feeds. Quite how this would adapt to the home is another matter. But from a cinema perspective it looks capable of producing a genuinely three-dimensional sound that is significantly more realistic than what we can currently re-produce with 5.1 or 7.1 surround sound. In my opinion, regardless of whether it’s Binaural, Ambisonics, Dolby Atmos or something else entirely that leads the way, if 3D audio can genuinely make recorded sound appear more realistic and therefore aid the narrative of a TV programme of film, it’s certainly a technology advance worth pursuing. Unlike some of the more overhyped 3D developments I could mention. Surround Sound Processors UpMix Surround Audio Stereo to 5.1 Decoder: Used on OB trucks to create 5.1 content from live stereo sources, archived material and adverts that UpMix Surround Audio Decoder need to be inserted. DTS Neural Surround™ transforms any stereo signal into a surround sound experience with individual audio elements placed perfectly within the surround environment. DownMix Surround Audio Encoder DownMix Surround Audio 5.1 to Stereo Encoder: The DTS Neural Surround™ DownMix encodes 5.1 surround sound to an LtRt stereo mix that accurately represents the 5.1 original and can be used for Mono2Stereo Quad Mono to Stereo transport and archival. Synthesizer Processor Mono2Stereo Quad Mono to Stereo Synthesizer Processor: Used extensively at sports events for making surround beds from mono mic sources, DaySequerra's Mono2Stereo uses a DTS proprietary algorithm which produces an artifact-free, wide soundstage with natural, spectrally balanced stereo, from mono content. 34 | TV-BAY MAGAZINE