When you walk into a movie theater, you usually see 12 to 16 speakers hanging on the walls. In addition, there are typically four systems behind the screen and hidden from view. What’s up with that? How do we get today’s 5.1 channels distributed to them and what’s changing?

The movies pioneered multichannel sound. Fantasia in 1940 had five loudspeaker channels^[i], and that was the first introduction of surround sound to the public.  But even in 1940, the engineers found that if they played the two surround channels out of just two loudspeakers, those sitting nearby would get creamed with level, while those sitting closer to the front hardly heard them in a mix. So the idea of an array of loudspeakers to play the surrounds has old roots. In fact, the two theaters equipped for Fantasound used many loudspeakers to reproduce the two surround channels.

So the idea that the number of loudspeakers you see represents the number of channels is wrong; many may be driven by one input signal. The most common configuration today is 5.1, where there are three main channels, left, center, and right, behind the screen, along with one or more subwoofers. So that’s 3.1 of the channels counted. The other two channels drive the left and right halves of the array of loudspeakers in the room, with the back wall speakers split between left and right.

Several years ago, pressure to get sound literally to come from behind you led sound designer (and multiple Oscar^®[ii] winner) Gary Rydstrom to ask for a separate rear channel^[iii]. The problem for cinema is that if you sit in the middle of the house and sound pans from the fronts to the surrounds, it only seems to come from your sides, because those are closer to you than those on the back wall. So it’s not really surround. By having a separate back surround, the effect can be overcome. Commercial implementations of this are Dolby Surround EX and dts Surround ES in theaters. These might be called “quasi 6.1” systems, because there is not perfect separation of back from sides, but usually good enough for the effect to work.^{[iv] [v] (more…)}

Paul Ottoson’s surprise double Oscar for sound editing and mixing on Sunday night for The Hurt Locker was dramatic. Rarely has anyone won two Oscars on the same show – the last time I remember it was to Walter Murch for picture and sound editing of The English Patient in 1996. Ottoson’s sound Oscar was shared with the production sound mixer Ray Beckett, who pulled the location duty in Jordan.

The Ottoson-Beckett pair also won the Cinema Audio Society’s award for best mixing of a feature film a week earlier. On that occasion Ottoson was very choked up compared to his Oscar performance, as the CAS is composed only of a few hundred people, all with significant mixing credits. As primarily a sound designer and editor in his previous over 100 film credits, he made the leap to mixing, and succeeded beyond his dreams with the recognition of his new peers in mixing.

The overall sound crew on this $11M budget picture was small: 15 people!  That’s tiny even by today’s shrunken crew sizes, down from years ago due to digital editing and automation. Assisting Ottoson as sound effects editor was Jamie Hardt, a 2000 graduate of USC Cinema where I teach. I remember him well, as he worked in the sound dept. as a technician as well as being a student. It is the biggest reward of teaching: seeing grads make it in the tough field of H’wood.