How to Wire a Dual 4 Ohm Subwoofer

Wiring a subwoofer brings questions about ohm loads and proper power distribution. Many of the subwoofers in use today have dual-voice coils that add to the wiring decisions. When dealing with numerous subwoofers, the options become numerous, and calculations require more steps. Luckily, to wire one dual-voice coil subwoofer is a much simpler process. In just minutes you can wire your subwoofer to work with whatever amplifier you choose to power your system.

Difficulty: Easy

Instructions

Things You'll Need:

• Screwdriver
• Speaker wire

1. Locate the two voice coils on the subwoofer. There will be a positive and negative terminal on each voice coil. Note the charge on each terminal. Often they will be color-coded: red for positive and black for negative.

2. Cut three lengths of speaker wire--two to run from your amplifier to the subwoofer and one to reach from one voice coil to the other on the subwoofer. Strip a small amount of plastic casing from each wire end, allowing a section of exposed wire to connect to terminals.

3. On a two-channel amplifier, bridge the connection by connecting an end of one of the longer wire lengths to the positive terminal on one channel of the amplifier. Connect one end of the other longer wire to the negative terminal on the other channel of the amplifier. On many amplifiers, the terminals to use when bridging will be labeled--if not, use the outside terminals.

4. If you have a mono amplifier, connect one end of a longer wire to the positive terminal and one end of the other long wire to the negative terminal. Use a screwdriver to tighten the connections.

5. Connect the wire running from the positive terminal to one of the positive terminals on the subwoofer. Connect the the negative wire running from the amplifier to the negative terminal on the other voice coil of the subwoofer.

6. Connect the third wire to the open positive terminal on the subwoofer and the open negative terminal on the other voice coil of the subwoofer.

7. Make sure all wires are secure and power on your system to test the connections.

Tips & Warnings

• Wiring in this way causes your subwoofer to run at 8 ohms, which will function safely with any car amplifier you choose.
• Make sure that you are connecting the wires to opposite voice coils, or you will use only one of your voice coils--limiting your subwoofer's output.