| Video Noise August 2004
Optimizing Home Theater
Loudspeaker Selection
Everybody wants to sell you speakers for your home
theater. Unfortunately, few buyers understand the compromises different types of speakers
can impose on a system’s sound.
In an ideal surround-sound system setup, all speakers
would:
- be identical in every way;
- be "full-range" -- they would produce the deepest
bass, the highest highs, and everything in between; and
- be placed the same distance from the listener -- in other
words, the listener would be in the center of a circle surrounded by the speakers.
Anything that strays from these ideals imposes compromises
on the sound of a surround system. For speakers to be full-range, they must be physically
large. Most full-range speakers I know of are large, imposing, and expensive.
The absolute worst surround system would comprise five to
seven speakers, each different from the rest, and no subwoofer: a flea-market-special
surround system.
Some compromises are almost mandatory, however. Consider
the center-channel speaker: what would you do with a center speaker 4’ to 8’
tall and 1’ to 4’ wide? Such a speaker could weigh 80 to 150 pounds, and there
would be no place to put it except behind a projection screen (if that’s what you
use). This is done in movie theaters and in some extravagant home-theater systems, but for
most people, the center speaker must fit above or below a direct-view monitor: a TV with a
big picture tube, or a rear-projection TV using small CRTs, a DLP chip, or LCD panels.
Compromise may be necessary to get a center-channel speaker you can actually live with.
Subwoofers
Subwoofers are a conundrum. Most of us have to have them to
keep the cost of the other speakers reasonable, but subwoofers themselves are mostly big
and expensive. You might be tempted by one of those tiny subs that don’t measure much
more than a foot on a side, but beware -- I’ve seen such subs move across the floor
by themselves because they just weren’t heavy enough to stay in one spot.
Furthermore, tiny subs rely on extraordinarily large movements of their small cones,
which, in my experience, produce more distortion than do cones that don’t have to
move quite as far to produce the same sound levels. Like it or not, in general, larger
subwoofers produce better bass than smaller subwoofers.
I can offer some possible relief: If your subwoofer budget
is in the $300-$1000 USD range, get a $500 subwoofer from Hsu Research (www.hsuresearch.com). You have to
spend more than $1000 to get a better sub, and some of Hsu’s offerings will perform
better than subs costing three times as much. If your subwoofer budget is just $300,
it’s worth waiting or sacrificing to get the Hsu VTF-2 Mk.II ($499) -- its bass is in
another realm altogether. And if you absolutely cannot spend more than $300 on a sub, get
Hsu’s STF-1 ($299).
Your home-theater dealer will want to sell you a
"matched system" from a single manufacturer. They will come up with all sorts of
stories about how someone else’s subwoofer can’t possibly work as well with the
speakers as the one the manufacturer makes to sell with them. That would be bad
information. Get the best subwoofer you can afford, regardless of the manufacturer.
All identical
The typical home-theater speaker system includes two front
speakers that are larger than all the other speakers, a center-channel speaker that’s
different from every other speaker in the system, and surrounds that are the smallest
speakers in the set. That’s three different speakers in one system, when our ideal
system would have five to seven identical speakers. Sounds from that ideal system will
combine more seamlessly; sounds produced by more than one channel at the same time will
image better and produce a more believable illusion of space.
Dealers will also make all sorts of excuses for the
center-channel, front, and surround speakers being different sizes and shapes, and
possibly not even sharing the same drivers. In general, the less expensive the speakers
are, the more varied those dissimilar speakers will sound. The smaller your speaker
budget, the more insistent you should be that all speakers are identical. When you get up
to relatively sophisticated speaker systems, the chances are better that the manufacturer
has put some effort into matching the sound of the different speakers in the system.
Other compromises
Many people seem to think the ultimate home theater is one
in which the speakers are built into the walls. In my experience, in-wall speakers
don’t sound as good as freestanding speakers. But the in-wall speaker business is
booming, partly because of whole-house sound-system installations and home theaters that
are designed by interior decorators rather than home-theater enthusiasts. If you want the
best possible sound for your home theater, stay away from in-walls.
On-wall speakers are mounted on the wall but have
their own enclosures, and can solve some of the acoustical problems of in-walls. Some
on-walls can come very close to the sound of freestanding speakers because their cabinets
are not subject to the in-wall limitations of stud-width depth and flush mounting.
A final tip
Interior decorators and do-it-yourselfers are often drawn
to white or off-white speakers for home theaters. Consider this: speakers are like air
pumps. They suck air in, then blow it out. Whatever covers the speaker drivers becomes an
air filter, and air is dirty. Look at your furnace filter, the front of your TV, and your
hanging light fixtures. White or off-white speaker covers, whether metal or fabric, will
get very dirty over time and require cleaning to look reasonably new again. Unfortunately,
cleaning textile speaker covers is usually not possible with anything more effective than
a vacuum cleaner’s upholstery brush. Over time, cleaning metal speaker covers can
remove the finish so that bare metal begins to show through in small spots. Gray speaker
covers are about as light as you might want to go to avoid hassles with visible dirt.
...Doug Blackburn
db@hometheatersound.com |
