Home-Theater Speaker
Systems
According to the Consumer Electronics Association (CEA), a
home theater can be as simple as a pair of loudspeakers connected to a big-screen TV. As
far as it goes, they're correct -- you can enjoy such a system and it will be a richer
experience than simply watching TV with the set's built-in 2" speaker.
But it's not what most of us would call home theater. We
all know what home theater really means: surround sound. To get surround
sound, you need an encoded source and a surround-sound
processor, but most importantly, you need speakers.
Until recently, surround sound meant 5.1 channels -- which
is to say five loudspeakers, configured as left front, center, right front, and left and
right rear, plus a subwoofer to handle extremely low sounds. These days there are 6.1,
7.1, and even 8.1 surround systems in existence, but it remains to be seen if the public
will embrace them. So let's call 5.1 surround our default norm for the moment.
At each stage of acquiring a surround-sound speaker system,
we have to make certain choices. Taken as a whole, this multiplicity of choices can seem
intimidating, but taken one at a time, none of them are all that difficult.
Speakers, more than any other component, are intensely
personal choices. It's hard to find a truly bad loudspeaker these days -- even inexpensive
loudspeakers have gotten pretty accurate -- but that doesn't mean you'll like everything
you hear. You must audition loudspeakers before you buy them. When you do audition
speakers, take along music you know and like, but also be sure to listen to some
spoken-word material, such as a news broadcast.
Does the music sound full-bodied or does it sound tinny?
Does it move you? Does it make you want to keep turning up the volume -- or even worse,
turn it off altogether? Does spoken word sound natural -- or is it chesty sounding? Can
you easily understand it? This is extremely important because when you watch a movie, you
will want to understand the dialogue.
There are two ways to set up a surround-sound speaker
system. Some people contend that discrete digital soundtracks, such as Dolby Digital or
DTS, sound best with five identical loudspeakers and a subwoofer. Others believe that,
since they don't contain as much information as the three front channels, the rear channel
speakers don't need to reproduce the full frequency range. There's some truth to this --
at least as far as film soundtracks go. However, as surround sound for music becomes more
popular, it may not always be the case for musical recordings.
If you opt for five identical loudspeakers, you don't need
to devote much thought to either the center or surround speakers. But let's say you
already have a pair of loudspeakers and you want to add a center-channel speaker -- what
do you look for? First, you need to make another decision. Some people maintain that all
three front speakers should be identical -- others call for a different type of
loudspeaker for the center channel.
In the early days of surround sound, some companies
produced small, cheaply made speakers for the center channel, but it's a bad way to go.
The center-channel speaker is probably the most important single channel in movie
reproduction -- it contains almost all the dialogue and at least as much of the special
effects as the left and right channels. Choose an underachiever and you'll struggle to
hear what's going on in movie after movie.
If you have a pair of high-quality loudspeakers you'd like
to build a home-theater system around, you're best off choosing a center-channel speaker
that matches them tonally. This may or may not mean they will be made by the same company.
That's not a bad place to start, but choose based on what you hear, not solely on the
brand name. Most surround-sound receivers allow you to listen to one speaker at a time --
if you pan from left to right listening to one speaker after the other, you can hear how
close a tonal match a given center-channel speaker is to your left and right fronts. When
the music or film sounds the same in all three speakers, you've got a match.
The last thing to choose is surround speakers, and once
again you have a choice. You can buy direct radiating loudspeakers (the regular
kind, like your other speakers) or you can buy dipoles. Dipoles are speakers that
project sound to the front and rear. Many people like to use them as surround speakers
because they can project a diffuse soundfield, one that puts the listener in the null
position -- in other words, the sound surrounds you but you can't pinpoint its source.
Movie theaters achieve this diffuse soundfield through the
use of multiple speakers arranged along the sides and rear of the theater. Dipoles achieve
this effect with just one speaker per side. The downside to dipoles is they tend to cost
more and they require room in which to work. If you're strapped for either space or cash,
you may prefer to go with direct radiators.
Some people feel that surrounds don't need to reproduce the
entire frequency range, since most surround effects don't involve deep bass information --
others want to hear as much as possible from all five channels. It must be said that the
smaller and more unobtrusive the surrounds, the easier it is to place them so they
disappear, both visually and sonically.
The last element in your surround-sound speaker system is
the subwoofer. A subwoofer reproduces the low bass information on a movie's soundtrack.
Ever since Star Wars, films have increasingly relied upon bass for impact --
especially in action and adventure movies. If that's your cup of tea, you'll want a
top-notch subwoofer.
Most subwoofers sold for home-theater use have built-in
amplification and crossover electronics. All you have to do is plug them in and connect
them to your AV receiver's .1 or LFE (low-frequency effects) output. Most high-quality
subwoofers use 10" or 12" drivers -- although a few use 15" monsters -- and
are powered by internal amplifiers ranging from 75 to 150W. They can cost as little as
$350 or as much as several thousand.
There's one more category of speaker system for
home-theater use and that's the type known as Home Theater in a Box (HTIB). These are
primarily sold as a convenience -- you get a surround-sound processor and five speakers
plus a "subwoofer." These can be, unfortunately, very low-quality units which
combine five tiny little speakers with a "subwoofer" that barely reproduces
midbass frequencies, much less low bass. On the other hand, some conscientious
manufacturers, such as Sony, Polk Audio, Denon, and Onkyo (to name a few) now offer
surprisingly high-quality offerings in this category. A good rule of thumb is whether or
not you recognize the manufacturer. Well-known and respected companies aren't going to
risk their reputations for a quick buck, but if you've never heard of the company, all
bets are off. Even so, an audition is always highly recommended.
Okay! Now you've got your A/V receiver and your 5.1
surround-sound speaker system. You'll probably want some pointers on how to set the whole
shebang up. Lucky you -- that's our next topic!
...Wes Phillips
wes@onhometheater.com
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