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Buyers
Guides > Speakers and surround
sound systems
Introduction
The revolution in digital
technology that has swept through the world
of domestic, consumer electronics in recent
years has resulted in a number of extremely
high-quality sources of video, and audio,
entertainment, in the form of DVD (“Digital
Video – or, sometimes, Versatile –
Disk”), and HD (“High Definition”)
television broadcasts, for example. Huge,
widescreen, television receivers, high in
resolution and contrast, and deep in colour,
cater for the visual elements of a true,
home theatre experience and the increasingly
sophisticated consumer of today demands
audio capabilities of the same high calibre
– the capabilities of digital surround
sound.
The aim of surround sound
is to provide an engaging, realistic listening
experience, by immersing the listener in,
or “surrounding” the listener
with, sound. This is achieved by recording
multiple, discrete, or individual, sound
channels, on, for example, a film soundtrack,
and reproducing each channel on its own
dedicated loudspeaker, situated to the front,
to the side, or to the rear of the listening
position. Sound, therefore, appears to emanate
from a full 360 degrees around the listener,
such that the distinct source of each sound
is not easily located – just as it
wouldn’t be, if you were really riding
pillion on Steve McQueen’s motorcycle
in “The Great Escape”, or co-piloting
Tom Cruise’s jet fighter in “Top
Gun”.
Surround Sound Formats
Dolby Digital is the industry
standard for both DVD and HDTV broadcasts,
and allows the recording of 5 main, independent
sound channels, to carry the dialogue, music
and other effects, for example, and a further
LFE (“Low Frequency Effect”)
channel to carry the low-frequency bass
effects – imagine the Tyrannosaurus
Rex in “Jurassic Park” and you’ll
get the idea. Dolby Digital is often referred
to as a “5.1” channel format.
A second, competing, 5.1 channel format
is available, in the form of DTS (“Digital
Theatre Systems”), which is in fairly
common use in commercial and consumer applications,
although, unlike Dolby Digital, it is not
a standard format for DVD and HDTV.
For the more adventurous,
extended formats do exist. Dolby Digital
EX, for example, allows an additional centre
channel – making it a “6.1”
channel format – that can be reproduced
through one, or two additional speakers,
and similar comments apply to the extended
DTS format, DTS-ES. Dolby Pro Logic IIx
takes things still further, effectively
converting 5.1 channel input into 6.1, or
even 7.1 channel output, and, for a truly
next-generation audio experience, there
are the latest, “lossless” codecs
(short for “compression / decompression
algorithms”) of Dolby TrueHD and its
competitor, DTS-HD Master Audio, designed
to take advantage of recent developments
in HD optical disk technology. Dolby TrueHD,
for example, has been adopted for use in
the HD DVD and Blu-ray disk formats, and
can, theoretically, at least, support up
to 14 discrete sound channels (although
both standards are currently limited to
8).
Surround Sound Speakers
Surround sound speakers come
in many shapes, sizes and configurations,
but perhaps the most popular is a 5.1 channel
configuration, comprising a front centre
speaker, front left and right speakers and
rear left and right speakers, plus a subwoofer
for low-frequency effects. Home theatre,
“in a box”, solutions, provided
by many manufacturers, are likely to conform
to this configuration, and, indeed, are
likely to be more than adequate for an average-sized
living room. 6.1, or 7.1 channel systems
require one, or two, additional, so-called
“satellite” loudspeakers, usually
positioned to the side of the listening
position. The Yamada H8550 Surround Sound
Speaker package, as an example, includes
5, 14-watt satellite speakers, and a 28-watt
subwoofer.
In terms of physical size,
surround sound speakers range from large,
floor-standing models, perhaps 3 feet, or
so, tall, through smaller, “bookshelf”
speakers, which can be mounted on shelves,
furniture, or a wall, to tiny satellite
speakers. The size that you can accommodate
will, obviously, depend largely on the physical
dimensions, and layout, of your listening
space, but do bear in mind that smaller
speakers will have limitations, in bass
and volume levels, compared to larger alternatives.
As a rule of thumb, it’s generally
a good idea to have front centre, front
left and front right speakers of roughly
the same size, and elevated to the same
height – unsurprisingly, roughly ear
height, when seated. Do remember, too, that
“unshielded” speakers are likely
to cause interference with picture quality
if placed close to a traditional CRT (“Cathode
Ray Tube”) television set –
thankfully, most speakers, nowadays, are
magnetically shielded, and interference
is not a problem with LCD or Plasma televisions.
Examples include Rimax Wireless Speakers,
only some 7.5 inches in height, delivering
3 watts per channel, with a range of over
150 feet.
One of the most important
aspects of a surround sound system is the
tonal balance, for example, of bass, or
treble, frequencies, between all of the
speakers. If there is a noticeable difference
in tone, as sound “moves” from
one loudspeaker to another, the source of
the sound will become immediately identifiable,
defeating the whole object of surround sound.
It is wise, therefore, if possible, to acquire
a complete set of surround sound speakers
from a single manufacturer, which will have
been matched for tone before they left the
factory. Voyager VYWSS splash proof stereo
wireless speakers, for example, can be individually
adjusted for channel, and volume.
Another aspect that cannot
really be overemphasised is the quality
of the cabling – assuming, of course,
that you don’t go for a wireless solution,
which is a possibility – that you
employ to connect your surround sound speakers.
Many systems are shipped with cables that
are just about, but barely, adequate in
quality (and, perhaps, length) and amazing
improvements can be made just by replacing
them. Look for cables with solid gold connectors
– usually a pretty good indication
of quality – rather than braided wires.
A/V Receivers
The other essential component,
of course, of a digital surround sound system,
is a digital A/V (“Audio /Visual”)
receiver, required to decode the incoming
video signal, and amplify and direct each
channel to its appropriate, dedicated loudspeaker.
Spending a little bit more – 30%,
or so, of your digital surround sound budget
is not unreasonable – on a A/V receiver
is likely to give you better overall sound
quality, more powerful amplification, support
for more surround sound formats (and possibly
better upgrade options), and more connections,
or interfaces – composite, component
and S-video, and, more recently, HDMI (“High
Definition Multimedia Interface”),
and the like – which may be important
if you want to connect other components
to your home entertainment system.
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