New movie will be the first to use eight discrete channels when it opens in cinemas; new system will give better home cinema, too

Toy Story 3 is due to open in cinemas in the States at the end of next week, and in the UK on July 23 – but while much of the hype has been about the fact it will be shown in 3D, things are also happening on the sound front.

It will be the first film to be shown in Dolby Surround 7.1, which uses eight discrete soundtrack channels to create a more enveloping sound and better localisation, as well as expanding the 'sweet spot' in which the best surround experience is available.

240 cinemas have already upgraded to 7.1 capability, according to Dolby, which is offering a free upgrade to those already using digital systems and Dolby's Surround and EX systems.

The company says Dolby Surround 7.1 is easy to implement with existing equipment, but gives filmmakers more control over the exact placement of sounds. Studios are already mixing in 7.1, with Disney saying that it will use it on forthcoming releases such as Step Up 3.

But until all cinemas are able to handle the eight-channel system, studios will have to make two mixes of every film released: one for the 7.1-ready locations, the other for those still using 5.1.

Until now, cinema systems have been limited to six channels simply because the sound was carried in the space between the images on the sprocket holes on film, with additional channels having to be matrixed into the existing space.

However, with more cinemas switching over to digital, it's possible to use the seven speaker locations arranged in four quadrants around the auditorium, allowing better steering in the rear channels.

This development will also find its way into the home, with movies on Blu-ray carrying eight fully-discrete channels, rather than surround effects being enhanced by the internal decoding and processing in home cinema amplification.

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