3E20.35 - High - Mid - Low Pass Filter/Crossover

Code Number:
Demo Title:
High - Mid - Low Pass Filter/Crossover
High Pass, Mid Pass, Low Pass Filter and Crossover
Area of Study:
Amplifier, Speaker, Wave Generator, Sound Color Organ, and Large Christmas Lights.

See also 3E20.30 in Oscillations and Acoustics and 5L30.36 in Electricity and Magnetism.

Connect one set of the speaker outputs to the sound color organ and the other set to the speaker.  Connect the Christmas lights to the sound color organ in any desired color scheme.  I like to use red as low, green as mid, and blue as high frequency.  As you sweep the frequencies with the wave generator from 0 to 11 KHz, the red, green, and blue should light up when the appropriate frequency ranges appear.  The amplifier master volume set at 5 appears to work very well. Some fine tuning of the pot controls on the color organ may be needed to get the appropriate responses.  Basically, this is a visual indicator of when a crossover changes frequency ranges.

Real crossovers can be viewed in the large speaker or with the individual units.

  • Erik Zavrel and Eric Sharpsteen, "Introducing Filters and Amplifiers Using a Two-Channel Light Organ", TPT, Vol. 53, #8, Nov. 2015, p. 478.
  • John E. Peterson, "Hearing by Bone Conduction", TPT, Vol. 17, #8, Nov. 1979, p. 531.
  • Lester Dwyer, "Color Organ", TPT, Vol. 9, #1, Jan. 1971, p. 47.
  • Jack L. Uretsky, "Comment on 'Phase Transition-Like Behavior in a Low-Pass Filter'", AJP, Vol. 71, #1, Jan. 2003, p. 31', AJP, Vol. 71, #12, Dec. 2003, p. 1320.
  • A. Lesne, "Comment on 'Phase Transition-Like Behavior in a Low-Pass Filter', AJP, Vol. 71, #1, Jan. 2003, p. 31", AJP, Vol. 71, #7, July 2003, p. 732.
  • H. Krivine, A. Lesne, "Phase Transition-Like Behavior in a Low-Pass Filter", AJP, Vol. 71, #1, Jan. 2003, p. 31.

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