We've assembled a lot of our research information on this page and
in a couple of linked files for anyone interested in learning more about
Home Theater.
What is Home Theater?
Typical Home Theater Components
Where to Put a Home Theater System
Ventilation Issues
Acoustical Problems
Front Screen vs. Rear Screen Projection
The Future
What is Home Theater?
Viewing movies in a Home Theater has become quite an event now with
all the special equipment available to create an experience that truly
rivals a movie theater. We think mostly of the image when we think about
"watching" a movie at home, but most of the really astounding advances
have been in audio. The first stage was the evolution of Surround Sound®,
which is the effect achieved by the Dolby Prologic® technology. It
basically decodes and converts 2 channel, stereo audio from a laser disc
player or VCR into 4 channels of audio. One channel goes to the left speaker,
one to the center and one to the right. The 4th channel goes to the surround
speakers, which add the aural "presence" so vivid in true Home Theater.
A further development in Home Theater audio was the result of director
George Lucas' efforts to achieve truer sound reproduction in movie theaters.
His Lucasfilm company patented the THX® Sound System for theaters and
later translated the ideas to the home format in the Home THX® Audio
System. What's confusing is that THX® is not a brand name for Home
Theater components, but rather a licensing technology to assure the highest
standards in those components for the best reproduction of theater-type
sound. What they strive for are: o Improved Dialogue Intelligibility o
Better Localization of On-Screen Sound (so sound pans realistically with
movements) o Enveloping Surround Sound o Wide Frequency and Dynamic Ranges
] So THX® has become the premier licensing standard for controllers,
power amplifiers, loudspeakers, acoustically transparent front projection
screens and audio interconnects. But if those terms aren't familiar to
you, you might want to check out our List of Typical Home Theater Components
before moving on.
Where to Put a Home Theater System
This is one of those subjects that depends on the individual. You have to ask yourself the question "Where do I most enjoy watching movies and/or television?" [Image] That question aside, you would probably do best to put a system in the basement. Controlling the light is usually easier in a lower level. By insulating the ceiling and walls of the theater space you can also keep a lot of sound out of the rest of the house and keep the disturbance of the other household member to a minimum. [Image] Another factor might be that, with a rear screen projector, a basement would give you the extra space for the equipment without eating up the valuable living space upstairs. equipment without eating up the valuable living space upstairs. That's a common problem in designing a home theater system: how to work large ugly equipment into the overall design of the house. It's a bigger deal than you might imagine. Certain elements of design will easily become overpowered by the size of the equipment, especially small items. One thing we ran into is that there is an optimum range of height for a person seated to view the screen. It may or may not fall in line with, let's say a countertop level you've got running around the room. Or maybe it interferes with an established soffit line. [Image] Our system was installed in a large open space with no adjoining spaces to expand an equipment room into, so we had to build a cabinet to house it. [Image] Our architect drew up the plans and we had a local cabinetmaker put it together. It was constructed of plywood with a cherry veneer to match the rest of the woodwork in the house. This material was also chosen for it's structural stability, it won't warp as easily as solid cherry would. It's more ecological because a small amount of cherry is used to make it. The end result is a material that looks like a solid hardwood.
Ventilation
If all the electronic equipment is enclosed in [Image] cabinets, it
can generate a lot of heat. In fact, we've heard of cabinets becoming so
hot that the clear coat finish has melted off the wood surfaces. That's
hot! The pieces that generate the most heat would be the projector, the
line doubler, the dss receiver, and the amps. To keep the interior of our
cabinet cool, we've installed 3 Whisper fans. They're not very large, about
4" in diameter and 1 1/2" thick, but they came highly recommended by audio
visual people we talked to because of their quietness. Our cabinet
is divided into three sections, the middle one being the largest to house
the projector, mirrors, and screen, and the smaller closet type cabinets
on either side where the equipment is located. Each cabinet has a fan mounted
in the top. The bottom of each is vented to let air in. Plus, there are
vents between the enclosures to allow air to circulate between them. One
thing to be concerned with is the sound a fan contributes to the overall
room noise. Obviously, with a home theater system you want to keep extraneous
noise to a minimum. That's why we chose this particular fan. Eventually
they will be switched on by a thermostat whenever the interior temp reaches
a certain level.
Acoustical Problems
With a home theater system, your goal is to recreate the same sound
in your home that the director heard on the dubbing stage when it was recorded.
But every room adds its own characterics to a given sound, and the same
speaker will sound different from space to space. [Image] The most elusive
enemy of the sound system is the standing wave. Standing waves are any
sound waves of a particular length that will be greatly enhanced by the
size and shape of the room and the way a room resonates. [Image] A square
room will create the most problems with standing waves and a room with
walls of different lengths will create the least. But unless you're building
your home theater from the floor up you probably can't do much about the
shape of the room, but try these steps to minimize acoustical problems:
o Keep subwoofers out of the corners which are the most notorious for standing
waves. o Move speakers around in order to change the way they reflect off
of surfaces. o Keep the walls "dead" with absorptive items like curtains.
o Furnish the room with big, soft furniture that will help keep sound reflections
to a minimum. o When you've made the room "friendly" to sound playback
use an equalizer to fine tune it.
Front Screen vs. Rear Screen Projection
If you're going to go with a video projection system then you'll have
to choose between a front screen projector or a rear screen. Here are some
pros and cons on each type of system: Front Screen doesn't require as much
construction. If you're working with a finished space you won't have to
worry about tearing out any walls. The projector hangs from the ceiling
above the audience. Because it shares the same space as the audience, it
takes up less room than a rear screen. The down side is that front screen
needs a totally dark space or the image will become washed out. If you
have difficulty controlling the light level in the viewing space then front
screen may not be for you. Rear Screen on the other hand will tolerate
more ambient light, you don't have to worry about keeping all of it out.
And you don't have to look at the equipment, it's hidden away as opposed
to be in the same room as the viewers. This helps to cut down the noise
made by the fans on the projector. But you're going to need more room if
you go this route. A rear screen mounted in the wall requires enough space
behind it for the projector and the projector's throw distance, which can
get pretty long. In our case it was about 7 feet. We were able to reduce
that by bouncing the image off of two mirrors and squeezing the projector
to screen distance into a 41" space.
The Future
Here are some quick notes on new technologies we came across that might
play a big part in Home Theaters of the near future. High Definition Television
(HDTV) will some day bring a larger aspect ratio to home theater. In other
words, you get a wider picture, more like a movie screen. And it has twice
as many lines of resolution so the clarity is increased. Run it through
a line doubler and the results are incredible. It's still in its infancy
right now but there is a high definition VCR on the market. Unfortunately
at this time, there are no movie titles available, only a couple of PBS
shows that were produced in high def. But work is being done to include
a couple of features by next year. For audio, we're just seeing the first
pieces of equipment with AC3 technology built into them. AC3 is a 5.1 channel
format which means it has 6 channels of discreet audio. The end result
is a more sophisticated, separated surround sound effect. Titles are being
produced with this technology right now. And in the next few years we should
start seeing new Digital Video Disks (DVD's) the same size as CD's that
will contain whole films.
