Tomlinson began his lecturing by talking about the revolution of sound in 1928 and how it changed the history of film and the lives of many. The way films were shot changed because the cameras had to be isolated due to their noisy nature and so everything that was filmed was static and almost theatrical. So with the advent of sound something else was lost in the process.
He began to do an illustration of the way sound can be perceived at it beginnings. The drawing is that of a small box and at its base is bounded by the frequency range, which is the range from base to treble. Treble was about all the details and during that time it was incredibly hard to get that sound off of film and back on to it again. The bandwidth or range of sound during that time was very limited and so the experience of sound was barely there.
The vertical part of the box represented the amplitude range, and that means the loudest sounds one can hear to the smallest sounds. This was also a very limited and dynamic range. During that time what sound engineers would do is play something very loud and then play something very soft and that way they contrast each other.
There were two dimensions to sounds back then and a third, the spatial aspect, was nonexistent. With the progress of history and war and so on sound started to get more developed and one of the people that set these advances in motion was Disney and his cooperation with the musical conductor Stokowsky. They began with the experimentation into stereo sound by 1934. That initiated the need for multi channel sound and “Fantasia”, 1939, was the first to do so. The channel at that time consisted of three only, left, right and center. So as it is known it was Disney himself who invented the idea of surround sound. The making of that system and its implementation at the time was very costly, limited, and sadly unsuccessful.
War world II happens and after that the popularization of television began and as a result less people began going to theaters and the industry crashed. The movie industry began to fight back and because of that many advances occur cinematically and also audio wise. By the eighties with the digital era sound advances happen also. In 1987 a committee of the Society of Motion Picture and Sound Engineers were asking how many channels needed to be on a motion picture print. Tomlinson’s response was 5.1, Left, right and center across the front, left surround and right surround and a single low frequency channel. The low frequency is needed because our ears cannot localize low frequencies well. By the time we get to this system the other two dimensions have been expanded and the frequency and amplitude range are in line with the audience and cannot be amplified any more than they already are.
5.1 was named by Holman in 1987 and came out on film in 1992 and became popular since then. What comes after this is the addition of more channels and from that comes the 10.2 sound system which is twice as good as 5.1. How far the number of channels can go is known and largely speculated but the most logical answer at the moment is 10.2.
The purpose of 10.2 is to allow much greater flexibility for sound designers and create a far more immersive environment for the audience. With these channels, it is possible to recreate the acoustics of nearly any location with astonishing realism. Holman found that the second most important sound wave to hit the audience - after the one from the source - is the one that comes from a point on the ceiling, halfway between them. This is because most rooms have hard and reflective ceilings, but the walls are semi-absorptive due to objects in the room; while the floor, usually covered with carpet, absorbs most of the reflected sound. So this first, overhead reflection reaches the ear at a slightly different time, allowing the brain to both localize the primary sound and compute the size of the room. By placing two speakers 45° above and to the left and right the audience, this key sound wave can be recreated. The other speakers can fill in the other major reverberations from the sides and off the back of the room, recreating a full acoustic signature. The strength of traditional 5.1 surround is that its left and right surround speakers are diffuse; they spread the sound around the entire area. This helps to prevent the " Exit Sign Effect" - audience members looking away from the screen at the source of a localized sound, not realizing it is part of the movie. However, this diffusion carries a cost in flexibility. Therefore 10.2 augments the LS (left surround) and RS (right surround) channels by two point surround channels that can more finely manipulate sound - allowing the mixer to shift sounds in a distinct 360° circle around the movie watcher.
The .2 of the 10.2 refers to the addition of a second subwoofer. The system is bass managed such that all the speakers on the left side use the left sub and all the speakers on the right use the right sub. The Center and Back Surround speaker are split between the two subs. The two subs also serve as two discrete LFE (Low Frequency Effects) channels. Although low frequencies are not localizable, it was found that splitting the bass on either side of the audience increases the sense of envelopment.
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