A brief history of home sound
Before I can get into what these speakers set out to achieve, I need to give a background on just what surround sound means for the home user. Please excuse my labe drawing ;)
From the first days of home sound, there was monaural – a single audio band. You placed however many speakers anywhere you wanted, but that was it:
This was replaced by stereo, little by little, starting in the 60s on stereo vinyl all the way to NICAM on TVs. This meant a different channel for left and right, allowing panning and positioning of people. For once, it made a difference where your speakers lay:
Dolby Labs decided to be all clever and invented Dolby Surround. This extracted a third channel called “surround” from the stereo signal. Noise that became muffled when played by both stereo channels was assumed to be for surround use, and was sent there. It’s that simple (well nearly). This surround signal could be played with one speaker, or two speakers playing an identical signal: or whatever; as long as it came from behind you. Commonly, this was used for a subwoofer:
The Dolby lads were chuffed with Surround, so quickly set upon the next version, Dolby Pro Logic. This was Surround, with a second generated channel: a “center” at the front (usually on top of the TV) for voices. Pro Logic titles, being very clever indeed, were backward compatible with old Surround decoders:
Then, not ones to rest on their laurels, Dolby managed to drag another channel out of thin air, and call in Pro Logic II. Like Pro Logic, it features back-compatibility, so Pro Logic II titles will play fine on Pro Logic or Surround setups, albeit in a weakened form:
Somewhere in all of this, Dolby struck upon an idea: why invent channels out of nowhere? The cinema had used 4 or more unique channels since the 80s, and perhaps it would make sense to allow this at home. Their Dolby Digital standard was adopted for use on the forthcoming DVD Video discs: highly compressed digital data passed to a decoder, then split into five satellite channels and a subwoofer channel. No guessing, just high-quality. DTStech’s Digital Theatre Sound (or DTS for short) works on a similar principle, but without the compression:
How does this affect you, the casual console gamer? Read on...
