Audio master

Audio pumped through multiple speakers placed strategically around a room, also known as surround sound, can help truly enrich your entertainment experience. Read on as Windows Middle East cranks up the volume...

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By  Jason Saundalkar Published  July 17, 2007

In the real world, we can hear and perceive sounds from all around us, rather than from just one direction, which is good, as this means we can interact and react with the surrounding environment more accurately. From a technology user's viewpoint, if you're playing a game or watching a movie, being able to perceive sound from all around in this way also makes for a far more realistic and immersive overall experience.

Surround sound technology, also known as ‘multichannel audio', when used with content that is designed with this type of system in mind, surrounds you with sound via the use of multiple speakers. In comparison, standard speaker systems, also known as stereo systems (or 2.1 set-ups), use just two forward speakers and one subwoofer, thus they can't really surround you.

To explain the benefits further, if you're playing a game using a surround system, and an enemy is walking up to your character from behind, you'll actually hear their footsteps getting closer only through the rear speakers. This is exactly how you'd perceive this situation in the real world and you can therefore react to it. Using a standard audio system, the footsteps would come through the forward speakers, so although you'd still hear them, you might think the attack was coming from the front.

Compared to standard audio set-ups, surround sound systems are far more complex and thus more expensive. In terms of the differences in hardware, the most noticeable aspect is that more speakers (or satellites) are used by surround systems. Even the most basic feature two forward- and two rear-speakers, coupled with a bass-pumping subwoofer.

In position

Each satellite speaker generates ‘positional' audio, meaning it only creates audio, as and when required. If, for example, you're watching a movie and the person on screen is being shot at from the front right, the satellite speaker sitting at the front right corner of the room will be the one responsible for pumping out the sound of that gun being fired.

Generally, speakers are used to create most sound effects, music and voices, while low-frequency sounds known as bass, such as the rumble of thunder, are handled by the subwoofer.

There are two types of subwoofer available; active and passive. Active woofers are capable of generating stronger, deeper bass, primarily because in an active system a dedicated power source is a necessity. They're also the better buy of the two. A passive subwoofer, in comparison, draws power from the amplifier and while capable of creating reasonable bass, these cannot really compare with active models.

Having surround speakers is only half the battle however; you'll also need a surround sound amplifier to drive the speakers correctly. A surround sound amplifier is different from a standard model because it can accommodate all of the surround speakers' connections. It can therefore receive an audio signal from a source such as a DVD player, separate the audio into its respective channels, and send it to the right speaker. Standard amplifiers on the other hand generally feature just left and right speaker inputs and so won't be able to power all your surround speakers. (And although high-end standard amplifiers can feature several speaker connectors, if you send a surround sound audio signal to these amps, they will simply send the same audio to all the speakers or only to the forward speakers and the subwoofer.

Surround sound amplifiers aren't always dedicated, external systems however. If you buy an off-the-shelf, budget home theatre system you may find that the subwoofer features an integrated amplifier. This is fine if you're looking to save space and don't plan to tweak your system much in future. If however you want greater flexibility, you should always opt for a separate, dedicated amplifier. These offer several advantages over built-in models including more power output and greater flexibility in terms of speaker inputs and the number of sources you can connect. As a general rule of thumb, opt for the best amplifier you can afford and build your home theatre system around that.

Surround sound systems manage to encompass listeners thanks to the number of speakers they employ. Initially they were were available in 4.1 and 5.1 configurations. With the former, you get two forward speakers, two rear (or surround) speakers and a subwoofer. With the latter, you will get a single centre channel (which is usually responsible for creating voices), two forward speakers, two rear speakers and of course, the subwoofer.

In recent years however, 6.1 and 7.1 multichannel systems have become available. 6.1 systems are similar to 5.1 configurations with an additional, rear centre speaker present. 7.1 set-ups however take things a step further and feature one centre, two forward, two side, two rear speakers, and a subwoofer.

5.1 is good to go

Despite the potential for an even better surround sound experience from 6.1 and 7.1 systems, 5.1 models are still the best buy for most, if not all, homes here. There are several reasons for this, the main one being that most movies and games on the market today only feature audio that's 5.1 ready. Thus, if you invest in a 7.1 system, and feed it 5.1 audio content, the extra side left and right speakers will rarely be used or, if they are, will likely just produce the same audio being supplied to the rear speakers.

Additionally, 6.1 and 7.1 systems carry a considerable price premium over their 5.1 counterparts as a result of their extra speakers and more potent amplifiers. 7.1 systems also require more space because not only do you have more speakers, you'll also have an amplifier that's more complex and thus bigger in size.

It's worth mentioning however that developers have begun developing content with 6.1 and 7.1 systems in mind, so if you opt for such a system now, you may reap the benefits in the future.

Surrounded by sound

In a nutshell surround sound is a generic term for any speaker set-up that includes rear speakers (also known as surround speakers). These receive different audio signals than the front speakers and this helps to create an immersive or three-dimensional effect. The most popular surround systems at present use five speakers and a subwoofer.

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