Home Theater Product Guide
Everyone seems to be talking about home theater but few people know much about it. Introduced in audio components around 1990, home theater was designed to simulate the surround sound that you'd experience in a movie theater.
This 5-channel sound would be encoded in commercially made videocassettes, laserdiscs, and DVDs and played through a sound system that would decode it. Several TV programs were also broadcast with surround sound. Home Theater combines television and sound for a totally new experience in home entertainment.
Home Theater involves two of our most widely used senses - seeing and hearing. Though the concept seems new, the technology of integrating sight and sound as communication and entertainment has evolved over many years.
Movie theaters have attracted countless billions of visitors over the years and continue to attract billions more.
In the 1930's, engineers began exploring 2-channel sound for special effects. The first dual-channel sound came was used in the film King Kong (1933) to help make the roar of a lion seem more real. This new system became known as stereophonic sound. By 1939, several movies were released with stereo soundtracks, particularly Gone With the Wind and Fantasia.
Stereo proved to be a very successful way of producing sound. Each channel had a speaker. Two speakers were used to reproduce the sound of a left channel and a right channel. It helped create the presence of a live stage, mixing left and right to seemingly create a multidimensional experience that seemed realistic.
Enhanced stereo sound was introduced using a system developed by Dolby Laboratories at an IMAX film Expo'67. The first commercial film to use this system was A Clockwork Orange (1971), though it was released to the theaters in mono (1-Channel).
By 1974, movie studios and theaters began introducing multi-channel soundtracks that literally surrounded you. Sensurround was the first system, developed for Universal Pictures, and used for Earthquake and Battlestar Galactica. A Star is Born (1976) was the first Dolby Stereo film released with a simulated matrix surround soundtrack. The release of Star Wars, in 1977, with Dolby Surround sound, introduced the masses to an experience where you could hear sounds from the front, side and rear. You could actually hear (and feel) an Imperial Starship cruise above you and Apocalypse Now was the first film to introduce a true split-surround Dolby 5.1 channel sound format. Dolby Digital was introduced in 1992 and, interestingly, Dolby Digital EX was introduced with Star Wars: The Phantom Menace (1999). Currently, movie theaters employ 6 and 7 channel surround sound systems. There are currently over 30,000 movie theaters, around the world, that can process and play Dolby Digital encoded movies.
By the 1980's, multiple channel sound systems were developed for home use as, with the popularity of the home videocassette recorder, these movies had become available for playback through home systems.
Though most commercial audio recordings are still using stereo, the increased popularity of videocassette and DVD movie media have brought about the need for a surround sound method of reproduction. When Sound and Image are combined in the optimum way, a greater feeling of reality is added to the movie experience; that is the goal of Home Theater- to make you feel as if you were part of the movie. We now have the ability of enjoying the encompassing sound of a movie theater experience in the comfort of our home. Welcome to Home Theater. This guide helps show you what you need to know about buying and setting up a home-theater system.
Stereo (2 Speakers) vs Home Theater (6 Speakers)
Most audio CDs are recorded using 2-channel stereo. For audio only, stereo is considered ideal. We have 2 ears and, for the most part, a stage is usually placed in front of us. Only 2 speakers are required - one for the left channel and one for the right channel. The left and right channels are mixed during recording to create a realistic playback presence, as if we were seated at the best seat in the house. Stereo is alive and well.
Home Theater is a 5.1 channel sound system that is designed to copy the surround sound that you'd experience at a quality movie theater. Most movies (made after 1980) have 4 or 5 channel soundtracks. The most popular home surround sound system is Dolby Digital and 6 speakers are required. Many current sound systems that can play home-theater can also play stereo.
5 Speakers deliver the 5 surrounding channels. There are 3 speakers in the front. There's a front-left speaker, a front-right speaker, and a front-center speaker. The front-left speaker and front-right speaker may also act as your two speakers, when listening to stereo sound. The front-center speaker is usually placed on top of or adjacent to a TV screen because this speaker plays the sounds that would be heard directly from the theater's screen. In the rear, there are two additional speakers for rear-left and rear-right surround channels. Most of the sound comes from the front speakers.
The 6th speaker has little to do with the surround effect. That's why it's 5.1-channel sound instead of 6 channels. This speaker is a Subwoofer. It delivers extremely low audio frequencies that your other speakers may not be able to deliver. It usually has its own built-in amplifier to deliver the sound. Its main function is to deliver richness to overall sound quality to emulate the deep sounds that would be heard in a large movie theater.
Dolby Pro Logic, Dolby Digital and dts
Dolby Pro Logic was the first split surround system available for home sound systems around 1987. With 4 or 5 channels, it used 5 speakers instead of 6. Early Pro Logic used 4 channels - front-left, front-right, front-center, and rear. Around 1990, Pro Logic became 5 channels by splitting the rear channel into rear-left and rear-right. Though almost all home systems and components still have a Dolby Pro Logic mode, and a newer version, Dolby Pro Logic II is available, Dolby Digital Surround sound is now the most popular system.
Most available home theater sound systems incorporate Dolby Digital Surround, usually accompanied with the term AC-3. AC-3 is a special system that compresses digital audio information to occupy less space on a DVD, for example. There is no loss of sound integrity.
Dolby Digital was introduced in 1992 with the release of the film, Batman Returns and is present on virtually every soundtrack on every major film. Several TV shows are broadcast in Dolby Digital and some video games are also designed for play with Dolby Digital Surround. It is considered the audio standard for HDTV, and for Digital and Satellite TV systems. Featured in home systems around 1997, Dolby Digital uses a 5.1 channel surround format. The ". 1" refers to the addition of a subwoofer that handles very low frequencies found in the soundtrack.
Another system, dts (digital theater systems), was introduced in 1993 with the release of Jurassic Park. Considered a competitor of Dolby Digital, dts uses a similar 5.1 channel soundtrack for surround sound. Far less movie titles are available with dts than Dolby Digital but most home theater surround sound systems are compatible to both systems.
Introduced in 1999 with Star Wars: The Phantom Menace, Dolby Digital EX is a 6.1 channel system. It adds the requirement of a 7th speaker - a rear center channel. This extra rear surround channel works with the usual left and right surround channels to produce even greater realism than ever. Several home theater sound systems are beginning to include this system as well.
Subsequently, dts-ES raises the bar over dts sound performance with its own 6.1 channel surround. Many systems that are Dolby Digital EX compatible are also dts-ES compatible.
Many home theater components offer a Virtual Surround Sound mode. It may also be referred as 3D Surround. This is mainly for sound systems that still use 2 speakers. It simulates a wider sounding field to seem like surround sound but really isn't.
How to shop for a Home Theater System: Approaches
There are different approaches to building a Home Theater System. To start with, you need a television. Many people who are looking for the maximum theater impact shop for the largest screen that will fit in the intended space (don't forget to measure!) and fit in their budget as well.
The next thing to consider is whether you want to buy separate components or look for a prepackaged home theater system. You may want to do a combination, such as buying a DVD player, Dolby Digital receiver, and a Home Theater package of speakers. These are the most common approaches.
Home Theater: Separate Components
Creating your own home theater sound system by purchasing separate components allows the ultimate freedom to select the best possible functions and sound performance to meet your tastes and needs. This selection process may take a while and may strain the wallet of a budget-conscious buyer. In the long run, you're building a higher performance system that can easily be upgraded in the future, as technology and your needs change.
A Receiver that has Dolby Digital (AC-3) decoding built in, in addition to Stereo sound is the heart and brain of your home theater component system. It integrates an amplifier, a control center, and a radio in one unit. It has input ports that allow you to connect other components - a DVD Player, a VCR, a TV, and more. It also has output ports that enable hookup of a home theater speaker system. Naturally, this receiver also serves the same Stereo purposes as older receivers when it comes to playing CDs, Tapes or Vinyl Records (some new models may not have a port that allows connection of a turntable).
The best source for visual and audio playback of movies is the DVD player. Movies released on VHS will usually contain the simplest form of Dolby Surround sound, but it will not equal the Dolby Digital sound on a good DVD disc. So a DVD player should be on your list at some point. All DVD players can also play a CD-Audio disc in stereo, so it can easily substitute for a CD player (a CD player, on the other hand, can not play a DVD). There are players that hold only one disc and there are changers that can hold several discs.
The next choice is speakers. A typical home theater will have 5 speakers plus a subwoofer. Although subwoofers are available in a variety of sizes, and can usually be placed anywhere in the room, since the human ear usually cannot locate the source of very low frequency sound. In spite of this, some people do not have a place in their room to put a subwoofer. The alternative in that case is to purchase larger front speakers that have sufficient sized woofers to reproduce the deep sounds of movie soundtracks without suffering damage. Because the accurate reproduction of these low frequencies requires significant amplifier power, most subwoofers include built-in amplification. If you're really trying to get the best home theater sound that Dolby Digital can provide, purchasing a subwoofer is a very wise move.
The speakers that represent the 5 main surround channels need to be positioned properly in your room to create the optimal home theater sound integrity. Most speaker manufacturers and audio critics will tell you that the best way to create "seamless sound" (the illusion that the sound is moving from one part of the room to another) is to use matching Front Left, Front Right, Rear Left and Rear Right; in other words, buy the same type of speakers for the Front and Rear, with a Center Channel designed to match these. If you intend to use your system to play stereo CDs, you should try to make sure that the Front-Left and Front-Right speakers produce satisfying sound, since these are also used in the stereo mode.
Component system owners have the choice of buying their speakers separately or in packages. Many leading manufacturers pre-package home theater speakers in matched sets of 5 or 6 speakers to help streamline your shopping time. Many of these packages produce deliver excellent surround sound. If you really enjoy stereo CD and radio listening, these packages may not meet your needs and you should consider purchasing your speakers separately.
People who enjoy using stereo headphones are in for a surprise. New headphone models will become available that are Dolby Digital Surround sound compatible. Dolby has developed a revolutionary way to experience the magnificence of surround sound in the privacy of your own ears - Dolby Headphone Processing. They incorporate a special signal-processing system that can take up to five channels of audio from any source and make it sound like it's coming from that many speakers in a real listening room. Listening to a Dolby Digital or Dolby Surround soundtrack, you hear the sound of five speakers: three in front of you, and a surround speaker to each side. When you listen to stereo material, you hear the sound of two speakers not at your ears, but out in front of you.
Home Theater: Prepackaged Sound Systems
The simplest way of adding home theater surround sound to your television is by purchasing a prepackaged system. It may just be the perfect solution for someone who doesn't want to bother with choosing, buying and assembling different components. The entire system has been matched and put together by the manufacturer and is ready for use out-of-the-box.
A typical system includes a DVD player or changer, a radio, 5 surround speakers and, in many cases, a subwoofer. Because DVD players can also play audio CDs, you can also use these systems for stereo sound. The key concept of these systems is that they're very easy to set-up and use. All you have to do is plug it into your wall electric outlet, connect the TV, and place the speakers around the room.
They can also be reasonably affordable. While systems using separate components might cost around $1,000 or more, prepackaged home-theater systems start at around $300.
In addition to adding a TV to the sound system, many have an additional connection port so you can add your VCR for playback through the system.
Selecting a Television For Your Home Theater System
For the best home theater effect, we recommend using a large-screen TV, 27 inches or higher, because movie theaters have large screens. Tube and rear-projection TV screens remain very popular. New flat-panel LCD and Plasma screens can be very large (up to 70 inches) yet are very thin so they take up little space. Most plasma screens can even be hung on a wall.
In the United States, most TVs are analog. Television is broadcast using a standard called NTSC (National Television Standards Committee), which typically provides a maximum display resolution of up to 525 lines, interlaced, with 480 actually visible. The usual TV has an effective picture resolution of about 210,000 pixels. A pixel is a dot on your TV screen that displays visual information. More dots mean higher image resolution - sharper details, more vivid color accuracy.
Over the last few years Digital TV (DTV) has been emerging in popularity. High Definition TV (HDTV) is a high standard of DTV that also integrates Dolby Digital Surround. It is capable of producing 720p (1280x720 pixel progressive resolution) or 1080i (1920x1080 pixels interlaced resolution), with over 2,000,000 pixels. Enthusiastic videophiles claim that HDTV can provide movie-theater like video imaging on a TV screen and HDTV is presented in the 16:9 wide-screen format that is visually comparable to a movie theater screen (16.65:9). In this format, letterbox DVD images will completely fill the screen. HDTV will also be compatible to display current 4:3 analog presentation formats but those may not completely fill the screen.
Currently, few TV shows are broadcast in HDTV and few DVD videodiscs are compatible for use with HDTV sets. The Federal Communications Commission (F.C.C.) has mandated that all stations be capable of broadcasting HDTV by 2006. It is likely that all DVDs will be manufactured to be HDTV compatible by that time. They will likely be called HD-DVD discs.
HDTV sets are currently available in two ways - HD-Ready and HD-Capable. HD-Ready sets have the HDTV receiver/decoder built-in, while HD-Capable sets require the addition of an external receiver/decoder needed to receive digital broadcasts. In an HD-Capable set, the TV is essentially a monitor. You buy the receiver/tuner separately. The majority of HDTV sets that are currently sold are HD-Capable.
If you are considering an investment in adding a large-screen TV to your home theater surround sound system, you may wish to consider the possibility of HDTV compatibility.
Space and Decor
Home Theater systems have become very popular and home designers and decorators are beginning to confront and develop ideas to meet some very unique challenges.
Stereo systems use only 2 speakers, placed at the front of the room, usually beside the components. Dolby Digital surround requires 6 speakers to provide the 3-Dimensional physical depth that stereo lacks. Five speakers are directional. The 3 front speakers are placed at left, center, and right of your TV (assume that the TV is at the center of the wall, as in a theater). The 2 rear speakers are best placed on the left and right sides of your seating area. If this is not practical, they can also be placed behind your listening seat, at the left and right sides of the room. The 6th speaker, a subwoofer, is non-directional and may be placed almost anywhere in the room. In the case of Dolby Digital EX, which uses 7 speakers (where a rear center-channel speaker is added), it is advised to mount that speaker behind the seat.
Realizing that floor space can be very valuable in most homes, manufacturers of prepackaged speaker kits and prepackaged systems may use relatively small, wall mountable, speaker designs for the 5 directional speakers.
Positioning of a couch or chair as the primary viewing point depends on the size of your screen. Assuming a 27-inch or 32-inch screen, you should be seated about 8 to 10 feet from the front of the screen. These recommendations are geared to help provide the optimal home theater experience.
To accommodate the need for larger screen sizes, especially with the 16:9 wide-screen perspective, many designers are suggesting the use of flat-panel Plasma TV screens. First, Plasma screens are very thin - generally less than 4 inches. When compared with a tube-model TV that averages around 24 inches deep, the Plasma screen saves over 80% of space. Second, Plasma screens can be mounted on the wall (much like a framed picture) or hung from the ceiling so it occupies no floor space. This helps enable home theater to be experienced in a smaller area or room.
With many houses and apartments already enjoying the amazing qualities of home theater, HDTV, the eventual integration of computers and high-performance Internet access offer significant promises that home theater will grasp many new purposes and become vital toward extending our reach through the 21st century and beyond.
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