Speaker Placement for
Home-Theater Systems
This is a good time to stop for a moment and think. Go
ahead -- I'll wait patiently.
Okay, now ask yourself what you want to do with your
home-theater system. Many people want to recreate the movie-theater experience at home --
that means getting a really big-screen TV or a projector and creating a sound system that
reproduces surround sound. If that's what you want to do, it's really helpful to have a
dedicated room, 'cause all that gear takes up a lot of space.
But not every person or family has the space for a
dedicated room -- and not everyone wants to re-create the movie-theater experience.
That’s okay. Home theater, like audio, is all about what you want to do.
Maybe you don't want all those speakers in your
room. That's cool -- you don't have to have them. But you can make TV seem a lot bigger
than "lights in a box" if you add a pair of external loudspeakers to your
monitor. When the sound gets bigger, the whole experience seems bigger, and it doesn't
take expensive loudspeakers to sound better than the teeny, low-powered ones built in to
most televisions.
Here's what you do: Take an old stereo receiver (you can
buy 'em cheap at yard sales these days) and connect your TV (plus your VCR, laserdisc
player, or DVD player) to it. Now attach a pair of loudspeakers to the stereo receiver.
Sit down in your favorite chair -- which is probably more or less in front of the TV --
and take a piece of string and stretch it tight between your seat and the monitor. Mark
the string where it touches the monitor. Keeping it attached to your comfy chair at one
end, take the other end and describe an arc to the left and right of the TV. You want to
place your loudspeakers at two points along that arc equidistant to the TV. This means the
TV and the speakers are all the same distance from you -- which, in turn, means the sound
will inhabit the large space between the speakers and that any sound created by both
speakers will seem to come from the TV itself. You'll be amazed by how grand your TV
viewing will now seem.
If you're using small loudspeakers, you'll want to place
them on stands. Most hi-fi stores carry a wide range of speaker stands, some of them very
expensive. A sturdy pair is best, but you don't need to go overboard. The speakers should
be at or near your ear level when you are seated.
 If you do want to create a
surround-sound speaker system, the string trick is still a good first step, only now
you're placing three speakers -- left front, center, and right front -- along the arc
described by your crude compass. And, of course, things get just a little more complicated
with three front speakers. Not only should they all be the same distance from you, they
should be at similar heights. A large-screen monitor almost necessitates that you put the
center-channel speaker on top of it. That's pretty high for the left and right speakers,
so you may have to aim the center-channel speaker down at your listening position by
putting shims under it in the rear. In any case, you need to listen carefully to all three
speakers, trying to minimize the dispersion differences between them and the apparent
differences in height. Fortunately, most surround-sound receivers have test tones that
make this process a little easier. But only a little -- setting it up is always tedious.
That said, set-up is also the difference between a
great-sounding system and one that just sounds so-so, so take the time to get it right.
Where to place the surround speakers depends on whether you
have dipolar or direct radiating surrounds. What they both have in common is
that surrounds should never be aimed right at the listening position -- get 'em up above
your ear level by about two feet.
A dipole surround speaker will have several drivers in it
-- at least one facing forward along the side wall and another facing back along it. The
listener should sit in the null spot -- the spot between the front-facing and
rear-facing drivers. With the speakers properly placed above ear level, and with the
listener in the null, the listener will hear no direct sound at all -- it will seem to
come from all around.
Direct-radiating surrounds, on the other hand, should be
placed high on the side walls behind the listener -- but not on the rear walls.
There are tall stands and wall-mounted speaker brackets for
mounting surround speakers, although many speakers now have mounting arrangements either
built-in or included in their accessory packs.
Newer surround processors may also have accommodations for
another surround speaker or even another pair of speakers -- if you have one of these
newer surround modes, follow the instructions in your owner's manual for locating the
best-sounding position for it or them.
The subwoofer is probably the most difficult speaker to
place in a home-theater system. This is because deep bass interacts with each room in a
unique way. There will be areas where bass is reinforced and others where it is weakened
-- and whether the subwoofer is in one of these hot or cold spots, or you are,
either way they affect the sound. The real art of subwoofer placement is getting the sub
into an area where neither interaction overwhelms the natural sound of the bass.
There's a trick you can use for subwoofer placement,
however, that will save you lots of time and frustration. Since the effects of placement
are symmetrical, you can place the subwoofer in your preferred seating spot and then walk
around the room listening to a solo recording of a full-range instrument such as piano.
Take a roll of masking tape with you and mark several places where the sound of the sub
and your front speakers seems full, natural, and balanced. These will be good places to
try the subwoofer while you sit in the comfy chair. Continue to listen to the solo
piano music until you achieve a seamless blend between the sub and the front speakers.
When you think you have good, balanced sound, ask yourself,
"Can I hear the subwoofer working?" If the answer is yes, it's turned up
too high. You should never actually hear deep bass emanating from the sub itself. When a
sub is set up right, you'd almost think you weren't hearing it at all. But turn off the
sub and the sound will shrivel into a puny, flat fraction of what it had been.
Don't expect the sub necessarily to go between the front
speakers or even along a wall. The best place for it may turn out to be next to your
listening seat -- that's okay, every room is different. I once spent two days with Ken
Kreisel of M&K Sound Corp. as he measured my room with a precision laser, a calibrated
measurement microphone, and a computer suite of test equipment. After running every test
possible, we definitively proved that the single best location for a subwoofer in that
room was smack-dab in front of the door. It would have sounded great, but there was
the small problem that no one could have gotten in or out of the room.
So, we compromised and chose the next-best spot. It may not
have been perfect, but it worked. Sometimes that's all you ask your surround-sound
system to do -- but if you follow these simple set-up procedures, yours will do a
lot better than that. It'll sound great!
...Wes Phillips
wes@onhometheater.com
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