Hardware Guide

This is the Hardware guide which describes the main components of a home cinema, including surround sound processors, amplifiers, video sources and televisions.
HARDWARE

 

The amount of equipment you use in a home cinema system can vary a great deal depending on what you want to get out of it at the end, or simply because of budget or space considerations. This page gives you an introduction the the different hardware that can be used in a home cinema, and how each component can help you to get the system you require.  
   

VIDEO SOURCE

You'll need a source component that reads the sound and picture information from the software and distributes the different signals to the other components within your system. Video sources include Laserdiscs, DVD Video discs, VHS video tapes and television broadcasts. As with source components in hi-fi systems, the video source should be the best quality component you can get, and should be the strongest part of the system. A good amplifier, decoder or television will not make up for a poor quality source signal, just as a good stereo amplifier or top-quality speakers will not compensate for a poor CD player.

 

Toshiba SD-2109 DVD Player
 
   

SURROUND SOUND DECODERS

A Surround Sound Decoder is a component that decodes a surround sound signal from the source soundtrack and distributes the decoded audio channels to the correct part of an amplifier and on to the speakers. Decoder circuits can be found within A/V amplifiers and A/V processors, or in a separate decoder unit that is connected between the source and the amplification. All the basic A/V amplifiers and processors contain a Dolby Pro-Logic decoder. Digital decoders for Dolby Digital or DTS are also found in some A/V amps and processors, or in external units that can be added to an existing home cinema system using a 6-channel input.

The Sony Dolby Digital decoder shown below is designed to be connected to a home cinema amplifier or receiver using a 6-channel phono connection. The sound source, such as a DVD player, is connected to the Sony using a digital cable that carries the audio data from the player to the decoder. The decoder then processes and separates the data into analogue signals that are passed to the amplifier through the 6-channel connection for amplification and playback through the speakers.

 
Sony EP90ES AC-3 decoder
Sony EP90ES Dolby Digital Decoder
 
   

A/V AMPLIFIERS

Normal stereo hi-fi amplifiers amplify the two audio channels of a stereo source. Home Cinema amplifiers, known as "A/V" amplifiers, contain amplification for five speakers and an output for a sub-woofer. There will also be a built-in Dolby Pro-Logic decoder, with some amplifiers also containing a Dolby Digital or DTS decoder in addition to Dolby Pro-Logic. The basic A/V amplifier will have several phono inputs on the back for connecting any source equipment with a phono stereo audio output, including DVD players, video recorders, CD players and radio tuners. An increasing number of A/V amplifiers also come equipped with video inputs and outputs. If you plan to add an external digital decoder at a later date, make sure that the amplifier has a 6-channel phono input.

Most A/V amplifiers now come with decoding for Dolby Pro-Logic, DTS and Dolby Digital, and still have a 6-channel input. Although this input can be used to add another digital surround sound decoder, it is unlikely that this is what it will be used for. More likely, it will be used to connect a DVD-Audio player to the system that will contain its own high quality sound decoding for upto 6 channels.

A simple A/V amplifier is a good way to experience Home Cinema, with all the amplification and Dolby Pro-Logic decoding taking place within one box. Because everything is in a single unit, they generally are quite easy to set up and have great surround sound performance. They also have the advantage of being able to accept many audio sources due to the number of inputs on the back. On the down side, stereo audio performance from CD player isn't usually up to the same standard as even a lower priced hi-fi stereo amplifier, usually due to the fact that the A/V amplifier is built for five speaker surround sound and all the extra circuitry tends to spoil the normal stereo signal. A/V amplifiers with Dolby Digital and DTS are even more practical by removing the need to add external processors for digital surround sound later.

 

Sony TA-N9000ES Dolby Digital / DTS Decoder and pre-amp and the TA-N9000ES milti-channel A/V power amplifier
 
   

A/V RECEIVERS

Receivers perform exactly the same task as an A/V amplifier, except that the receiver has a built-in radio tuner.

 

Sony STR-DB930 Dolby Digital / DTS / Pro-Logic Receiver
 
   

A/V PROCESSORS

You may have a good hi-fi system that you don't want to get rid of, but you would like to build a home cinema that shares some of the hi-fi components, such as the same front stereo speakers. The main problem is that a hi-fi system uses a two-channel stereo amplifier and two front speakers. Using an A/V amplifier in place of the hi-fi amp would mean a general reduction in the stereo playback quality of your hi-fi sources, as detailed above. You also have the problem of connecting the front stereo speakers to the new home cinema system - an A/V amplifier needs to amplify five speakers including the existing two hi-fi speakers, so unless you want two pairs of front speakers beside your television, one from the stereo hi-fi amp and the other from the A/V amp, another option is needed.

The A/V processor is a unit that connects to an existing stereo hi-fi amplifier through the amplifier's tape loop. It contains amplification for only the front centre and the two rear surround speakers, and will have a built-in Dolby Pro-Logic decoder. All the audio sources are fed into the hi-fi amplifier using the stereo phono inputs. The signal passes out of the amplifier's tape loop to the processor where the surround sound is decoded. The processor amplifies the front centre and the rear surround channels, while the front stereo channels are separated and passed back through the tape loop to be amplified by the hi-fi amp. Additional units for decoding digital surround can be added to the processor if it has a 6-channel input.

The advantage of using a separate processor is that normal stereo playback of sources such as CD is not harmed by the surround sound circuitry. The processor is only active when the amplifiers' input selector is set to the correct source (such as a video recorder) and the 'tape monitor' is switched on, or the 'listen' selector is set to 'tape'. When the processor is in use, the stereo amplifier amplifies the signal fed to it by the processor, rather than the original, undecoded audio. However, careful setting-up of the surround processor will be required due to the fact that two separate amplification units are being used to hear a single soundtrack, and they will each need to be adjusted correctly to prevent one amplifier overpowering the other.

 
 

SPEAKERS

For a real home cinema, you need a minimum of five separate speakers to hear the full surround sound effect, whether you use Dolby Pro-Logic or one of the better digital surround formats such as Dolby Digital. Two speakers are placed at the front of your listening position, at either side of the television. These speakers carry the main music and effects sound from a movie soundtrack. A specially designed centre speaker is placed above or below the television which carries the speech of the characters on the screen. This locks your attention to the television regardless of where you sit in the room. Two rear surround speakers are placed either at the sides or behind the viewing position. In a Dolby Pro-Logic based system, these speakers carry a single mono effects channel that creates an "ambiance" and enhances the sound from the front speakers. In a digital surround system, each of the two rear speakers receive a separate "discrete" signal and therefore operate in stereo, making accurate placement of sounds possible anywhere around the viewing position.

Matching of the speakers is important and varies depending on what type of surround sound you are using. In a Dolby Pro-Logic system,your priority should be matching the sound quality of the front three speakers in order for sounds to pan from left to right. A mismatched centre speaker will collapse the soundstage as this happens (this also applied to Dolby Digital and DTS systems). The rear speakers can be chosen with a little more freedom. Dolby Pro-Logic surround outputs a low powered, limited bandwidth mono signal to the rears for ambient effects only, so they can be smaller and normally don't need to be true hi-fi speakers as required for the front. However, matching speakers all round is still the best option, and allows easy upgrade from Dolby Pro-Logic to a digital surround format in the future without needing new rear speakers. In a digital surround system, the front three speakers should be matched as with a Dolby Pro-Logic system, but the rear speakers need to be chosen with a little more care. Digital surround uses a full bandwidth signal to each of the rear speakers. It is necessary to include good quality rear speakers that can receive signals from the amplifier as loud as the main front units, preferably by using the same speakers as the ones used for the front left and right.

Many companies offer dedicated home speaker packages with a full set of speakers that are designed to work well together, such as the package from Acoustic Energy, shown below. This is a simple and cost effective way of buying speakers, and is nearly always less expensive that buying the same speakers in separate pairs.

In a Dolby Digital or DTS system, there will also be a separate channel for connecting a sub-woofer, known as the "LFE" (Low Frequency Effects) channel. Generally, I have found this to be a worthwhile addition to any system in medium to large rooms, or in systems with fairly small speakers. In small rooms, the bass produced by the main speakers may be adequate on their own. What you want to try and avoid is adding a powerful sub to a system within a fairly confined space - you run the risk of overpowering the main soundtrack, and maybe even shaking the plaster off the walls! Try and listen in a dealer's demo room, which are usually small and can give a good indication of the added effect that a sub-woofer would make.

There is another option for people who don't like the idea of big speaker boxes all around the room, and for systems that are for Home Cinema only with no stereo hi-fi playback required. The method is to use a package consisting of five very small satellite speakers and a sub-woofer. The satellites are small and can often come in a number of different colours to match with wall decoration. Because they are small, they carry high frequency treble signals with no bass (bass drivers are not usually included). The bass is provided by the separate sub-woofer and adds power and depth to the directional surround sound provided by the satellites.

 

Acoustic Energy AE Series Home Cinema Speaker Package
 
   

TELEVISION

You will also need a monitor for viewing the video picture. In most Home Cinema systems, the television is used only to view the picture - the sound is sent to external amplifiers and speakers while the television sound is turned right down. With this in mind, the main factor to consider when buying a new TV is the size and quality of the screen, although TV's with surround sound should be considered in some cases which I'll explain in a moment. Widescreen is a great feature of the latest video sources, mainly DVD-video and some DigitalTV channels, so a large screen 16:9 set over 32inches screen size should be considered. But don't discount the regular 4:3 televisions when making your choice, as large 4:3 screens can display a widescreen picture in a 'letterbox' mode that may be similar or even larger than a widescreen TV, although you would get the familiar black borders at the top and bottom of the screen when watching a widescreen presentation. Bear in mind that the 4:3 picture displayed on a wudescreen set will have the borders at the sides of the picture.

There are a large number of televisions, both 4:3 and 16:9 widescreen, with their own Dolby Pro-Logic or Dolby Digital decoders and these come with the extra separate speakers needed for surround sound. Additional inputs on the back of the TV allow the connection of a variety of sources, including digital signals from DVD players. The advantage of these models is that it's a simple way to get into home cinema with the minimum cost and without having boxes hanging around the room. If you are upgrading your existing television and want a basic surround sound system without all the hastle and expence of a separates home cinema system, a surround sound TV is a great option. Setting up is easy and the sound quality is good from most users who don't demand the best surround sound quality, or for occasional home cinema use, although they can rarely perform to the same standard as a dedicated separates home cinema system.

Televisions, or monitors, come is a variety of forms, such as the normal CRT 4:3 or 16:9 widescreen models, upto rear projection, front projection and plasma. Visit the Televisions section for more information.

 


Sony VEGA 32DS60S Surround Sound Television with FD Trinitron™ Flat Screen