How to Connect Three Subwoofers to a Two-Channel Amp

Wiring subwoofers into a vehicle adds low-frequency sound.

Subwoofers are special speakers made to play low-frequency sounds. Car audio can greatly benefit from the addition of subwoofers because most car speakers are unable to play lower frequency sounds. Powering the subwoofers requires an amplifier to drive the speakers. The configuration of the amplifier is dependent on the number of speakers and the impedance of each speaker. Hooking up three subwoofers to a two-channel amplifier creates a unique setup configuration. Wiring subwoofers to amplifiers is recommended for those with audio wiring experience.

Things You'll Need

• Screwdriver
• Speaker wire (20 ft. or more)
• Wire strippers

Instructions

1. Determine speaker and amplifier impedance. Check the boxes that the products came in or the manufacturer's website for exact specifications. Wire at the lowest possible ohm (usually 2 ohm) that is stable with the amplifier. Ensure the subwoofers used are dual voice coils; otherwise, setup of three subwoofers will be very difficult.

2. Determine the length of the speaker wire that will connect the amplifier to the subwoofer box. Measure out and cut the wire using the wire strippers. Strip the positive and negative of both sides of the wire, leaving approximately 1/2 inch of bare wire exposed. Connect one end to the bridged mono out of the amplifier (this is almost always the "Right" channel).

3. Run the speaker wires in parallel for dual voice coil speakers. Connect the original speaker wire to the first subwoofer, connecting only one of the positive dual coils. Connect the negative speaker cable to the third subwoofer's negative coil.

4. Connect a short piece of wire for each of the two coils for both positive and negative terminals on all three subwoofers. Cut and strip two more short wires, connecting the first sub's negative coil to the second sub's positive coil. Repeat the same for connecting the second sub to the third sub.

5. Mount the speakers into the subwoofer box. Ensure the amplifier is correctly wired and ready for operation. Turn on the vehicle and test for sound response from the speakers.

Tips & Warnings

• It is possible to wire three subwoofers using single voice coil (SVC) speakers, though the connection usually lowers the ohms to a level too low for most amplifiers to operate. Attempting to run an amplifier out of its ohm range can result in permanent damage to both the speakers and the amplifier.

References

• The12Volt: Subwoofer Wiring Diagram