Sound Advice: Surround on the Cheap - Part 1

Hal Robertson
September 2005

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As home theater equipment gets better and cheaper, more and more viewers expect their video soundtracks to jump from multiple speakers. The built-in TV speakers just won't cut it anymore. For the video producer, this presents a quandary: do you continue to create mono or stereo soundtracks at the risk of alienating viewers, or do you invest the extra time and money required to make the leap to surround sound? In the first of two articles, we'll look at planning your upcoming multi-channel audio/video project, surround recording techniques and how to do it in the most time and cost-effective way.

Like many video producers, my production partner and I have wanted to do a feature-length project for some time. Abandoning reason, we decided to write, direct, shoot and edit the entire thing ourselves. One problem: there was no money for the project, so we opted to do everything possible with equipment we already had on hand. After all, independent films shot on DV are far more common these days. Early in pre-production, I knew I wanted surround sound, but couldn't afford to buy any of the fancy toys the big boys use. The next few weeks included heavy research into surround recording equipment, techniques and options. As it turns out, there are several ways to create a multi-channel product with minimum investment. In fact, unless you just want to buy some gear, you can probably duplicate our results with equipment you already own.

Surround sound comes in several flavors. The most common type is 5.1 channel surround sound. The five main channels are: Left, Center, Right, Left Rear and Right Rear. The point-one designation refers to the subwoofer channel which typically contains the low frequency signals from all channels. If you've recently purchased or experienced a modern home theater, you're familiar with the setup. Pop in a current DVD release and you're in for an emersive audio experience.

In addition to the number of channels, there are a number of standards for encoding surround audio. First, and most common, is Dolby Digital; formerly called AC3. Dolby is a household name today with its brand stamped on everything from VHS tapes to digital television broadcasts. Dolby Digital is encoded, which means it digitally combines the entire 5.1 mix into one bitstream. Without this encoding, you would have to create and maintain as many as 6 discrete audio channels throughout your project. Dolby's older surround system -- Pro Logic -- was used on LaserDiscs and VHS tape before the advent of DVD. Another encoding system is DTS. Originally designed for theaters, DTS (Digital Theater Systems,) has made its way into home theater too, but is available on fewer titles. DTS encoding yields arguably better sound quality, but is rarely included in video editing or DVD authoring software, so we'll stay with Dolby Digital.

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