Issue link: https://digital.copcomm.com/i/3788
Surround sound is a very broad term that covers many different audio configurations. The number of channels and the placement of the speakers vary with each format. 5.1 is the most common, but other types include many more channels and can even repro- duce the experience of height.The future will very likely bring new formats and applications of the surround experience, such as the highly versatile format of 10.2. 1 0 . 2 & TO M L I N S O N H O L M A N In 1987, Tomlinson Holman, chief scientist at Audyssey Labora- tories (www.audyssey.com) and professor at USC in Los Angeles, coined the term 5.1. Holman is a true audio pioneer whose for- ward thinking includes developing THX, and more recently, the 10.2 surround sound format. Holman's vision of 10.2 goes beyond the limitations of 5.1. "The original documents say that 5.1 is a sys- tem for the minimum amount of channels needed to accompany a picture," he says. "It was known to have limitations because it had to be put on a film digitally, so there was a cap on things with 5.1. "All through the period from 1987 to 1997, I was working on what the next logical step was from 5.1," he continues. "We know that everyone can hear the difference between mono and stereo. The same is true between stereo and 5.1 in the home theater market. So for me, the next obvious step was from five to ten. There are three basic reasons: physical acoustics, psychoacoustics and desires of filmmakers, composers and producers." 10.2 uses five front speakers positioned left wide, left, center, right and right wide.There are three rear surround speakers posi- tioned center, left surround and right surround. Interestingly, there is a choice of either left and right surround diffuse, or left and right surround direct, depending on the program's content. There are two height speakers positioned in the front left and right above the listener. Lastly, there are two LFE channels positioned left and right. 10.2 has a total of 14 electrical channels, but uses 12 speak- ers for playback. "Now, 10.2 is a bit of a fudge, because we have found that if you could sit perfectly in the center, you still could tell where the speakers are placed if you turned your head around," explains Holman. "So, I added two more channels so that we have two types of rear surrounds to choose from. The producers and content creators can choose between localized [direct] surround channels for specific events, or general [diffuse] surround channels for things like ambiences or reverberations." He says there are two reasons to have two low frequency channels at 120Hz. "The first reason is with the combined 10 channels, the power level requirement for a single LFE would quadruple its size! So, it's a lot easier to have two subwoofers since they hardly cost anything regarding the bandwidth size.The second reason is that it allows you to make a left or right difference in the low frequencies.True, some people may disagree that you can de- tect left or right with the low frequencies, but it is there for those who want it. Ultimately, 10.2 is 14 electrical channels but I call it 10.2 speaker locations." One of the most exciting aspects of the 10.2 format is the ability to reproduce height. "Height relates to psychoacoustics," says Holman. "As you raise stereo speakers in front of you, the imaging holds up ver y well. Because 10.2 can reproduce height, the sequence I would most like to see done in 10.2 would be the attack on Pearl Harbor." Though 10.2 is not commonplace yet, it is starting to take hold. Holman understands the difficulties of introducing a new audio format. "We do envision this format everywhere, but it's a bit of a chicken and the egg problem. We know that it is not going to sell until there is more software for it.There is progress being made; it is embedded in Apple's QuickTime and called TMH 10.2. And, there is space allotted for 12 channels in the digital cinema format. So, right now we have about 25 items of program material. We keep adding more content so that we can become embedded in people's consciousness." 10.2 ver y well may be the future of surround sound. One of the most logical steps toward the wide spread use of 10.2 might be IMAX, especially due to the stereo height channels. Holman would welcome the standardized use of 10.2 for IMAX, but he envisions 10.2 being used for any type of media and having a much wider audience. "It would be a set of computer files that have 12 channels which could be set with metadata," he explains. "The metadata would tell the audio how to be reproduced and play in a 10.2 large room, or in a 10.2 small room, or a regular 5.1 room. It could even include how to play it in 4 channels in the car, or the best possible mix for an iPod, and so for th. It would be all one big data file with all these side streams saying what to do with the audio based on what your situation is. It would be tai- lored to fit every possible media. Different mixes could be made and the mix data would be recorded and sent to DSP in the home. This was the vision 28 years ago when they got star ted. Now today, it's not crazy at all. "That's where I see surround sound going," continues Hol- man. "It will be really hard to convince the music in- dustr y and others to follow through, but, the metadata is the answer. 10.2 can be done in a scalable fashion to be down-mixed to fit your choice of number of speak- ers. It is this concept of scale- ability that makes 10.2 suitable for everyone." 7 . 1 S D D S & G R E G P. RU S S E L L Sony's 7.1 surround sound format is called Sony Dynamic Digital Sound, or SDDS for shor t. At Sony Pictures Post Production, (www. sonypicturespost.com) supervising sound mixer Greg P. Russell has recently mixed films such as Transformers: Revenge of the Fallen, Angels & Demons and nd d Regardless of the format, the goal is for the audio to envelop the listener. By Ron DiCesare Sony's Greg P. Russell mixed Cloudy With a Chance of Meatballs and Transformers: Revenge of the Fallen (opposite page). CREDIT: TRANSFORMERS: REVENGE OF THE FALLEN