They've Got You Surrounded
Sydney Morning Herald
Monday April 17, 2000
The nation's hi-fi retailers report that, thanks to DVD, most consumers have quite happily converted from stereo's two channels to DVD's 5.1 channels. They also report that most are happy to invest in the six loudspeakers required to faithfully reproduce 5.1-channel surround sound from DVD (front left and right speakers, a centre channel speaker, two rear channels and a subwoofer for the low frequencies). But can you really get surround sound with five-and-a-bit loudspeakers?
Dolby Laboratories, which invented Dolby Digital 5.1, doesn't think so. It has recently added an extra rear channel, called an "EX" channel, to its 5.1-channel system. Luckily, you don't need any extra software to activate the EX rear centre-channel - any DVD movie will do - but you do need an EX decoder.
Yamaha thinks that nine channels are necessary for true surround sound. Its latest RX-V1 home-theatre receiver contains not only a Dolby EX decoder, but a further two "front effects" channels. These are placed above the TV screen, to give the sound an impression of stretching from floor to ceiling as well as from the left to the right wall.
If your eyes are glazing over at the thought of all these speakers dotted around your lounge room, you should know that both Yamaha and Dolby are erring on the side of caution. Jan Blauert, in his book Spatial Hearing, estimated that more than 20 channels were necessary in order to faithfully reproduce 3D sound.
Michael Gerzon, the British mathematician known as the "father of surround sound", says that for a true 3D representation at least a million channels are required. Tomlinson Holman, who developed THX for movie house Lucas Film, thinks a 10.1 channel system is just about right, because it produces an excellent sensation of height, eliminates the front/back confusion that sometimes happens with 5.1-channel audio and is still attainable in an ordinary lounge-room with existing technology.
The number of channels is one thing; the quality of those channels is another. Yamaha's RX-V1 uses discrete output transistors for each of its channels, whereas many other manufacturers use integrated circuits. As a result, the RX-V1 returns better sound, lower distortion and higher output power, with 110 watts per channel for the main and surround channels and 35 watts per channel for the front effects channels.
Instead of cooling the transistors with noisy fans, Yamaha mounts them on large aluminium heat sinks; never again will the suspense be spoiled by the sound of a cooling fan switching on.
Yamaha is one of the few companies to manufacture its own Digital Signal Processing (DSP) ICs to simulate the acoustics of real venues - 18 are included inside the RX-V1. If you'd rather create your own sound effects, the RX-V1 gives access to the underlying raw processes - including reverberation times, delays and levels - via an easy-to-use (and easy-to-reset) on-screen control menu.
Overall, Yamaha has loaded the RX-V1 with so much onboard power and performance that it'll probably take other manufacturers at least a year to catch up.
Greg Borrowman is the editor of Australian HI-FI Magazine.
Info file
Yamaha RX-V1 Audio/Video Receiver
Price: $6,249
Yamaha Australia Pty Ltd
Level 1, 99 Queensbridge Street, Southbank, Victoria 3006
1800 682 705
www.yamaha.com
© 2000 Sydney Morning Herald