DISCOVER

# How to Build Speaker Crossovers

Updated February 21, 2017

Speakers come in an array of sizes, shapes and functions. Each speaker has a specific frequency range it was designed to handle. Crossovers use various electronic components to regulate what frequencies get sent to what speakers. Passive crossovers use capacitors and inductor coils to control these frequencies. Depending on the values chosen, a capacitor will pass high frequencies and block the lower frequencies. Inductors do the opposite. They will block the higher frequencies and pass the lower frequencies. These two components can also be placed in series to create a bandpass filter. In this configuration, only a certain range of frequencies is passed.

Decide the minimum frequency that will be sent to the tweeter. Use the following formula to calculate the size capacitor needed: 1/(2_Pi_f*R). In this formula, Pi=3.14; f=the frequency chosen in Hertz; and R= the impedance of the tweeter (speaker). Once that value is calculated, find a capacitor with a value within 5 per cent of the calculated value.

Connect the positive terminal of the speaker to the negative terminal of the capacitor.

Connect the negative terminal of the speaker to the negative terminal of the volume source. Connect the positive terminal of the capacitor to the positive terminal of the volume source.

Decide the maximum frequency that will be sent to the subwoofer. Use the following formula to calculate the size capacitor needed: R/(2_Pi_f). In this formula, Pi=3.14; f=the frequency chosen in Hertz; and R= the impedance of the tweeter (speaker). Once that value is calculated, find an inductor with a value within 5 per cent of the calculated value.

Connect the positive terminal of the speaker to the negative terminal of the inductor.

Connect the negative terminal of the speaker to the negative terminal of the volume source. Connect the positive terminal of the inductor to the positive terminal of the volume source.

Take one capacitor and one inductor that have the same values as those used for the tweeter and subwoofer speakers. Connect the positive terminal of the speaker to the negative terminal of the capacitor.

Connect the positive terminal of the capacitor to the negative terminal of the inductor. Connect the positive terminal of the inductor to the positive terminal of the volume source.

Connect the negative terminal of the speaker to the negative terminal of the volume source.

#### Tip

Each of the three positive cables and each of the three negative cables that go back to the volume source can be connected so that only one positive cable and one negative cable go back to the volume source. The volume source could be a receiver, amplifier, or car stereo.

#### Things You'll Need

• Capacitors
• Inductors
• Plastic splice caps or soldering iron with solder
• Tweeter speaker
• Mid-range speaker
• Subwoofer speaker
• 12-gauge wire