Feb
18
5.1 Surround Sound and Beyond
Filed Under Surround Sound
We all know about surround sound, right? yeah I knew we did but did you know that surround sound comes in many different flavors? Aside from the different formats (we’ll get into those later) there are actually five (at least) different surround sound configurations on the market today. First off we have 2.0 or stereo, while obviously not a proprietary Dolby Digital configuration it is important to be able to recognize this format as many older movies shown on cable and satellite use 2.0 audio. Why is this important you ask? many modern receivers allow you to apply Dolby PLIIx processing to stereo sources which will give you a surround effect with just two channels.
From there we move into the venerable Dolby Digital 5.1 which encompasses a huge portion of our overall surround sound world, from DVD’s to movies on cable and satellite 5.1 is the bread and butter channel configuration for home surround sound playback. Simply put if you’ve heard surround sound at home there’s a good chance it was a 5.1 configuration. A “5.1″ speaker system consists of a discrete channel for left front, right front, center, left rear, right rear and subwoofer.
Moving right along we get into the 6.1 channel configurations, 6.1 really took root in the latter half of the decade with the configuration finding its way into receivers at all price points, as a matter of fact its probably harder to find a 5.1 receiver now than it is to find a 6.1 capable receiver. 6.1 adds a back surround or “center surround” in some circles to the equation; this provides a smoother transition of sound between the individual speakers.
Never one to rest on their laurels (or risk stagnation among the buying public) the consumer electronic manufacturers came up with 7.1 surround which you guessed it adds a second back surround channel and uses processing to simulate true separation between the two channels. You’ll notice I said consumer electronics manufacturers and not studios, that’s because up until very recently (with the advent of Dolby TrueHD and Dolby Digital Plus) discs weren’t encoded with discrete rear surrounds. Note: for clarifications sake most of what I’m describing above involves legacy Dolby Digital and DTS associated with DVD and cable/satellite programming and not the new audio formats used with Blu-ray and HD DVD.
From there we get into the esoteric realm of everything beyond 7.1, which includes 8.1 and 11.2 as found in the Yamaha RX-Z11 and even up into the 13 channel configurations as demonstrated by Dolby at trade shows. In a nutshell these formats are flights of the manufacturers fancy and bear no real weight in the “normal” world of surround sound. Sure if you have a gigantic, cavernous abyss of a home theater the extra fill from a few more speakers may help with the transition from front to rear but this is a relatively unique application. That said I wouldn’t rule out real advancements on this front, but it would take more discrete channels than are currently available to see any real benefit.
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