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Implementation Guides

Surround-Sound Speakers

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PCQ Bureau
New Update

You can make a simple surround-sound setup with four speakers using the Hafler principle. If you have a two-channel stereo output and four speakers, then the two front speakers are connected between the earth, and the right and left channels. The rear two, or the surround speakers, reproduce

difference signal between these two channels. So, they are wired in series between the ‘left’ and ‘right’ signal lines. We’ve explained this in our February 2002 issue. But, one drawback in that was that the surround speakers were fed with an un-amplified signal and hence, didn’t produce enough volume. We got queries on this, so in this article, we’ll take care of this problem.

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Get down to it 

Open the speaker casing with the amplifier (with all the control knobs) you have marked as ‘front’. On the circuit board, trace the left and right terminals and mark them ‘L’ and ‘R’. You can take the signal from ‘before’ (Preamp) or ‘after’ the amplifier. If you take it from the Preamp, your surround speakers will have independent volume control, while in the latter, they’ll depend upon the front speakers. So, we recommend the former 

From the cable that goes into your sound card on the ‘surround’ set, cut off the end connector (stereo male connector). You will have three conductors: a shield (called common) and two different colored wires (for either channels). Twist the two channel wires together. This and the remaining shield wire form the two surround channels

Solder a small length of shielded cable across the ‘L’ and ‘R’ terminals you have identified in step 1, and connect it to the two leads in setup 2. Or, you can directly connect the two leads in setup 2 to the ‘L’ and ‘R” terminals

Connect the lead from your front speakers into your sound card, screw back the speaker casings, place them around you and play some music. You should be able to get the surround-sound effects

You need



Two pairs of amplified speakers. The chances are that you already have one set, so you’ll need to buy one more. Use the one with better Bass reproduction as the front (main) speakers. Keep a soldering iron, screwdriver and pliers handy. You might also need a length of shielded, two-conductor cable.

Ashish Sharma

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