NOOKS AND CRANNIES

Most hi-fi's or amplifiers have the speaker connections marked red and black, along with the cables to the speakers. Why is this polarity important? In my system it doesn't seem to make any difference to the sound which way I connect.

Sean, Belfast N. Ireland

  • If both leads are wrongly connected there won't be any difference, but if one speaker is connected correctly and one incorrectly, the speakers will be out of phase resulting in the stereo imagery being lost, and mono records sounding very fuzzy.

    J Vagg, Beckenham UK

  • The sound is reproduced buy your loudspeakers moving back and forth. If one of your speakers is wired up the wrong way it will be 'out of phase'. In other words it will be moving 'back and forth' while the other speaker is moving 'forth and back'. Your ears may not notice it but this results in the stereo seperation and sound quality not being as good as they could be. However if BOTH speakers are wired wrongly it shouldn't make any difference.

    Alan Keggie, Penarth, UK

  • The answer depends on whether you're a purist or not. If you're an audiophile, you'll notice, or pretend to notice, that the speakers 'are out of phase' if you connect red to black on just one of the speakers. What will be happening is that one cone will be 'pushing' while the other will be 'pulling air'. On the other hand, in a blindfold test,nobody could ever tell. Just don't let a hi-fi buff SEE your speaker cables the wrong way round!

    Marc Wisbey, Rome

  • If one speaker is wired correctly, and the other in the reverse polarity, one speaker will be 'pushing' as the other is moving in the 'pulling' direction resulting in a loss of volume. In modern stereo 'separation' much of the signal is delivered to both speakers, and differing polarities would have the slight efect of cancelling each other out. In industry one way of reducing noise is to feed a similar sound to the source, and this has a similar effect of reduction of volume, which demonstrates this principle.

    Jonathan, Lancaster, UK

  • Stereo speakers need to be "in phase", ie the bass driver (black round paper thing inside) in each moves in and out at the same time. This is controlled by the two wires. If one has the wires reversed, the speakers are out of phase and the bass component of the sound disappears. If the wires have no distinguishing colours, you can test for phase by facing the speakers 9" apart and playing music. If the wiring is correct they''ll sound as loud as you''d expect from the amplifier setting: if not, one is wired wrong. You can then swap the wires over in one speaker. Incidentally, the colours red/black or whatever don''t mean anything significant like live/neutral so it''s all perfectly safe.

    Carla, Crewe, UK

  • For a dramatic demonstration of this principle, place two out-of-phase speakers face to face. The sound will actually be louder when one speaker is turned off than when they are both turned on.

    Jim Dixon, St Paul USA

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