In this guide we take a broad look at buying speakers for the home. If you are building a home theatre system or a high-powered gaming rig, you'll most likely be looking at a surround sound system that's either 5.1 or 6.1. If it's music you're planning for, a stereo or 2.1 system is probably on the agenda. In any case, this guide will walk you through all the various formats and help you choose the right system for your needs.
Active and passive systems
Active or "powered" systems are those that come with an integrated amplifier. These are generally targeted at gaming and home theatre systems based around a computer, as they do not require an A/V receiver to drive them. Basic computer speaker systems are often 2.1, meaning they have two "satellite" speakers and one subwoofer. The sub-woofer is powered by an internal amplifier and the satellite speakers are also driven by an amplifier residing within the sub-woofer cabinet. Because these systems are powered, any line-level audio player can be plugged directly into them - be it a computer, CD player, DVD player, MP3 player or cassette deck.
On the other hand, passive or "un-powered" speaker systems are those that do not include a built-in amplifier. These are usually designed for home theatre use with a multichannel AV receiver. This is sometimes confusing as all systems that have a subwoofer incorporate an integrated bass amplifier. In other words, the subwoofer is always active, but in an un-powered system the satellite speakers are passive and require an amplifier to drive them.
Most powered systems use a small subwoofer cone ranging between 4 and 8 inches in diameter, whereas home theatre systems will usually range between 8 and 12 inches. The subwoofer's power output is measured in Watts (RMS), with 35 - 50 being standard for powered systems and 100 - 150 appearing in home theatre systems. Things to look for in a good subwoofer are solid wooden housing and a side or front air port. Those that have the port at the back usually need to be positioned away from a wall which can limit their placement in a room. Some other features to look for are a sizable external heat sink, which will keep the thing from overheating, and a sleep mode. This will automatically switch the subwoofer off when no signal has been detected for a certain amount of time.
Decoders and digital audio
For most non-powered systems, you will need a digital decoder to play 5.1 and 6.1 soundtracks. Some DVD players have built in decoding, as do most multichannel AV receivers. Some powered systems also come complete with a digital decoder built in. This means they can take a digital signal from a DVD player or PC and convert it into surround sound for multiple speakers. The benefit of having an integrated decoder is that you won't need to buy or connect an external one. This means fewer power supplies, minimal cabling and one less remote control. Check your DVD player and/or PC to see whether it has digital outputs and/or a decoder built in. If it has multiple analog audio outputs, you will be able to connect them directly to the amplifier without the need for a separate decoder.
Stereo and multi-channel systems
So far we have talked about 2.1 and 5.1 systems or, in other words, systems that have 2 or 5 speakers and a subwoofer. The word stereo means two channels, left and right, whereas multi-channel audio in home theatre systems usually refers to either 5.1 or 6.1 configurations. In 5.1 systems you have three speakers at the front - left, centre and right - plus two speakers to the sides or back. The subwoofer can be located anywhere in the room, as sub-bass is non-directional. A 6.1 system will have an additional speaker located behind the viewer, sometimes called the rear centre speaker. There are also 7.1 systems available, but it is worth remembering that there are no DVDs recorded in 7.1 (as of June 2005). Instead, 7.1 systems such as THX Ultra2 and Dolby Prologic IIx convert 5.1 and 6.1 formats into 7.1 for use with two rear centre speakers. Although there is some merit to the claim that a 6.1 soundtrack will always sound better with a 7.1 system, the real benefit will probably be enjoyed by gamers who have titles that actually support this many channels.