How to Build a Passive Crossover for a Speaker

by William Kinsey

Speakers are available in a wide range of sizes and shapes. Each speaker is designed to operate and reproduce a certain frequency range of sound. Speakers designed to handle high frequencies are called tweeters. The middle frequencies, including voice frequencies, are handled by mid-range speakers. The low frequencies are handled by woofers and subwoofers. Crossover networks are used to direct a certain frequency range to the speaker that can best reproduce it.

Use a crossover design program or a crossover design table to determine what values the inductors and capacitors will need to be to get the crossover points needed. The crossover points determine where the frequency spectrum is divided.

Look at the subwoofer. Connect one side of the chosen inductor to the negative terminal of the subwoofer. Connect the positive terminal of the subwoofer to the positive speaker terminal of the amplifier. Connect the negative speaker terminal of the amplifier to the second terminal of the inductor. The inductor is in series with the subwoofer for this setup. This is a low pass filter.

Look at the tweeter. Connect one side of the chosen capacitor to the negative terminal of the tweeter. Connect the positive terminal of the tweeter to the positive speaker terminal of the amplifier. Connect the negative speaker terminal of the amplifier to the second terminal of the capacitor. This is a high pass filter.

Look at the mid-range speaker next. Connect one side of the chosen inductor to one side of the chosen capacitor. Connect the other side of the capacitor to the negative terminal of the mid-range. Connect the positive terminal of the mid-range to the positive speaker terminal of the amplifier. Connect the negative speaker terminal of the amplifier to the second terminal of the inductor. In this setup, the mid-range, capacitor and inductor are all in series. This creates a bandpass filter.

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About the Author

William Kinsey lives in Concord, N.C. He started writing articles in March 2009, which have appeared on Autos.com and CarsDirect.com. He currently holds a Bachelor of Science in electrical engineering from the University of North Carolina at Charlotte and a Master of Business Administration from the University of Phoenix. He also has several years experience as an outside plant engineer and planner with AT&T. He also currently owns and operates Sophisticated Curves, an online fashion mall that caters to the needs of plus size women.

Photo Credits

  • photo_camera speaker element image by bright from Fotolia.com