How to Design Passive Crossovers

Speakers come in various shapes and sizes, and each is capable of handling different frequencies.

Speakers are designed to operate and reproduce specific frequency ranges depending on the type of speaker. A subwoofer will handle low frequencies, while a tweeter can handle high frequency. Any middle frequencies are reproduced by mid-range speakers. Passive crossover systems filter out the frequencies and direct them to the appropriate speaker, which enables each speaker to operate at its optimal range. You can design your own crossover system to improve the power and sound clarity of audio systems such as car stereos and amplifiers.

Things You'll Need

• 2 Inductors
• 2 Capacitors
• Tweeter speaker
• Mid-range speaker
• Subwoofer speaker
• 12-gauge wire
• Wire stripper
• Wire cutter
• Soldering iron
• Rosin-core solder

Instructions

Set Up

1. Use a crossover design program or table to determine the values for the inductors and capacitors you will need for your speaker.

2. Cut three pieces of 12-gauge wire each between 1 to 2 feet in length. Use wire strippers to strip approximately a half-inch of insulation from each end of the wire.

3. Select a volume source such as a car stereo, receiver or amplifier.

Subwoofer Speaker

1. Join the positive terminal of the speaker to the first inductor's negative terminal. Solder the connection for security.

2. Join one end of the first wire to the speaker's negative terminal and the other end to the volume source's negative terminal. Solder the connections.

3. Join the first inductor's positive terminal to the positive terminal of the volume source and solder the connections.

Tweeter Speaker

1. Solder the speaker's positive terminal to the first capacitor's negative terminal.

2. Attach one end of the third wire to the speaker's negative terminal and the remaining end to the volume source's negative terminal. Solder the connections.

3. Join the first capacitor's positive terminal to the volume source's positive terminal. Solder the connection for security.

Mid-range Speaker

1. Solder the positive terminal of the speaker to the negative terminal of the second capacitor.

2. Join the capacitor's positive terminal to the inductor's negative terminal and solder the connection.

3. Attach the inductor's positive terminal to the volume source's positive terminal and solder the connection.

4. Solder one end of the fourth wire to the volume source's negative terminal and join the free end of the fourth wire to the speaker's negative terminal. Solder the connection.

References

• The 12 Volt: Car Audio/Passive Crossovers, Capacitor & Coil Calculator
• Termpro: Designing Passive Crossovers
• Parts Express: How To Build Your Own Loudspeakers
• Filter Design: Higher Order Analog Butterworth Filter Designs, a Tutorial