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How to Steer the Low End With a Cardioid Subwoofer

Low-frequency audio is not directional, unless the sound source is about the same size as the wavelength of the frequency. A low note of 35 hertz has a wavelength of 33 feet. Thus, using a single directional subwoofer is impractical. In combinations called arrays, speakers behave differently than they do alone. A cardioid subwoofer array provides an effective way to direct low-frequency information with an efficient use of space.

Things You'll Need

  • 3 (or multiples of 3) subwoofers of same design
  • 2 or more channels of power amplification
  • Time-delay signal processor
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Instructions

    • 1

      Set up the subwoofer array by arranging speakers in groups of three, either horizontally or vertically, with the middle speaker pointing to the rear of the axis of the outer speakers.

    • 2

      Connect the outer speakers to one channel of an amplifier. Usually this is accomplished by using daisy-chain wiring from the power amp to the first speaker and from the first to the second speaker.

    • 3

      Connect the signal processing delay to the input signal of the amplifier channel that will supply the reversed speaker. The delay must be set to the equivalent of the distance of one-third the wavelength of the frequency you desire to control. Using the example of 35 hertz, one-third of the wavelength is 11 feet. Since the average speed of sound is 1,126 feet per second, 11 feet divided by 1,126 feet corresponds to a delay of 29 milliseconds. Set the delay for this value and connect the output of the amplifier to the reversed speaker.

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