Hook ?EUR(TM)em Up Right

By Team Digit Published Date
01 - Jun - 2006
| Last Updated
01 - Jun - 2006
Hook ’em Up Right
So you got a new set of 5.1 speakers. Great-way to go! Your next step would probably be to grab a bag of popcorn and settle down in front of your home entertainment system! Slide in that DVD and sit back. But what's this? DVD not sounding the way it should? Gunshots fired from behind being played by the front speakers? The ensuing irritation could make you want to tear out your hair, or maybe throw out your speakers, or both!

What you need is only to properly set up those sound boxes, and you'll be surprised at the mere minutes it takes to actually get it right. We throw in a helping hand, as usual, and believe it-you will hear the difference!

Why Six Channels?

A 5.1 speaker set is, of course, a six-channel system, that is, it is capable of reproducing six channels of sound, one of which is dedicated to bass (the subwoofer).

DVD audio, movies and gaming are the two areas where 5.1 speakers are in heavy demand. These are also the only two areas that fully utilise multi-channel audio, since music and movies from non-DVD sources are typically stereophonic. True 5.1 sound is positional sound, positional relative to the seated audience: DVD soundtracks are natively 6-channel, so positional sound is inbuilt. This means that gunfire behind and to your left will sound from exactly that channel-provided you've placed your speakers correctly, that is. With upmixing-adding virtual channels to a stereo source-the result is never good enough to compare with a true surround sound source.

Setting Them Up

Almost all motherboards today come with either 6-channel or even 8-channel audio onboard. With technologies such as Intel's High Definition-codenamed Azalia-a high definition, 8-channel audio architecture becoming more mainstream, the need to invest in a discrete multi-channel sound card is decreasing. We will use an onboard 5.1 solution for the purpose of setting up the speakers. Those with discrete sound cards can follow much the same procedure. So here's how to get the best sound from your speaker set:

1. First, ensure that your sound drivers are installed properly and up-to-date. Not only will these seriously hinder audio playback, they are notorious system resource hogs as well. Updated drivers ensure that bugs are ironed out.

2. Speaker wire plugs are generally colour-coded, and some manufacturers also mark the speakers as front left, rear right, and so on, which further simplifies the installation process. Most 5.1 speakers have the satellites connecting to either the subwoofer or an external box or decoder. Terminals are either of the wire clamp or plug types.

3. The front satellites are ideally placed a minimum of five feet apart. More powerful speakers can be placed further apart, barring space constraints. The satellites should be placed so that they fire in the audiences' direction. Similarly, the rear speakers are placed behind the listener, and in general should form a rough box formation with the front speakers. The centre speaker, which handles most of the vocals in a DVD movie, is ideally placed atop the monitor, directly in front of the user.

Typical Subwoofer back panel

Face the speakers towards you: if not, loss in clarity will result, since mid and high frequency sounds are direction-specific. The subwoofer can be placed anywhere in front of you, since low frequency sounds are not directional. Place the sub away from obstructions so it can fire properly, and try to maintain adequate ventilation around it. If you have an underpowered sub, place it near a wall to boost the bass.

4. If the speakers' connect plugs are colour-coded, attach the corresponding wires to the satellites. Some speakers come with wired satellites, making this step unnecessary. Move on and attach the other end of the wires to the rear of the subwoofer or decoder box, as the case may be. There should typically be six connectors at the back, with front, left and right, centre, etc. marked. It's good practice to coil up and tie the wires if they're too long, rather than let them hang around, as they tend to get knotted up, particularly at the point of connection with the sub/amp.

5. Now you need to connect the speakers to the sound card or motherboard. Sound card/ onboard outputs are usually colour-coded. Light green is for the front two channels, black typically denotes the rear speakers, while the centre and subwoofer are represented by an orange-coloured connector. If there's no colour coding, your sound drivers can help-use the troubleshooting feature.
6. You should have 5.1 sound selected in the speaker settings, which you can access via the control panel or the sound card drivers. All sound cards come with a setup Wizard or calibration Wizard-click on it. Here, too, select 5.1: some software will intelligently detect the speaker connects and show 5.1. These utilities usually play sounds from each speaker while indicating which speaker is playing by highlighting them on the screen. This is to ensure that the channels are right. If the speakers are playing when they should, breathe a sigh of relief-you're nearly through!

Final Subwoofer assembly

If a sound channel has got mixed up, you may have either connected the speakers to the back of the woofer/amp incorrectly, or the outputs at the sound card end have been plugged in wrong. The most common problem is of left and right or front and rear being inverted; simply swap the connectors.

The soundcard all hooked up

If the cables and the sound card sockets aren't colour coded, and if there's no sound from, for example, the centre speaker, you can use trial and error to get it right.

7. Another important tweak is the subwoofer crossover. In your sound card drivers, this will be shown as a slider bar. Generally, if set at a value like 120 Hz (typically, the crossover allows a range from 0 to 200 Hz), it means that any sound intercepted by the decoder unit below 120 Hz will be redirected to the woofer unit. The typical crossover frequency should be between 80 Hz and 120 Hz; anything higher than this can be handled by the mid range (squawker) drivers. Experiment and see what sounds best for you. The best sound may even vary from song to song, but there generally is an optimal setting.

Changing the Speaker Options in your soundcard panel

8. Slip a DVD movie into your drive. Start her up! You now need to calibrate the volume of the speakers. A good way to start is to set the overall (or master) volume to between 50 and 75 per cent, while playing around with the individual speaker volumes. The woofer volume should be kept at about 60 per cent; this is a comfortable volume that doesn't distort, and at the same time, doesn't intrude on the other sounds. Usually, the centre speaker is a bit more powerful than the other satellites, so it can be set at a slightly higher volume level than them without distortion. The centre speaker should, as a rule always be more powerful, because this is the channel that produces the vocals in a 5.1 movie.

9. Sit back on your settee, grab the popcorn (which you dropped in frustration earlier), and chill out!

Jargon Buster 
LFE: An acronym for Low Frequency Effects. The very term sub in the term subwoofer, means meaning sound below 50 Hz. A sub is typically capable of producing sound in the range of 35 Hz to 100 Hz. Some subs can go higher, though this is not really needed. A sub that can go lower than 35 Hz is good indeed, and the lower a sub can go, the more ideal it is for producing deep rumbles. Subs that go really low are also costlier.

Drivers: The driver is what produces the sound from your speakers. It consists of the enclosure (typically metal), a permanent magnet, and the diaphragm (often of paper). Speaker drivers are of three types, distinguished largely on the frequency spectrum they are built to reproduce. Tweeters are the smallest of the speaker drivers and can produce the highest-frequency sounds, like the tinkling of breaking glass. A good-quality tweeter can reproduce sounds up to 25,000 Hz. Squawkers are the mid-range drivers. They are typically 3- to 5-inch drivers with the ability to produce a wide spectrum of sound between the sub and the tweeters.

The subwoofer is the low-frequency sound producer, and is responsible for all the thuds and thumps. They are capable of playing sounds below 150 Hz. A sub also has the biggest driver, sizes range from 6.5 inches to 12 inches in diameter.

SNR: The Signal to Noise Ratio is a very important consideration for audiophiles and the discerning user. Very simply put, every sound channel carries, along with the actual audio content, a certain amount of signal interference or stray noise. This causes distortion in sound, and it is particularly noticeable at higher volumes, mainly because of the unit design imperfections. SNR is measured as a ratio. A typical good value for a speaker is 85 dB, with some higher end 5.1 sets having an SNR as high as 110dB. Speakers with an SNR of below 65 dB should be avoided at all costs!

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