Subwoofer Voice Coils
Voice coils transmit an amplifier’s power signal and shift the subwoofer’s cone in and out. Subwoofers are commonly classified as single or dual voice coil subwoofers. Dual voice coil subwoofers have two voice coils inside of the sub, while the aptly named single voice coil (SVC) subs have only one voice coil. Dual voice coil subs have more wiring flexibility than single voice coil subs, as you can wire them in series, parallel or combination.
|Dual Voice Coil (DVC)|
|Single Voice Coil (SVC)|
A single voice coil sub has only one positive and one negative terminal, along with a single strip of wire wrapped around the sub cylinder. In contrast, a dual voice coil subwoofer has two pieces of wire, and each one wraps around the sub cylinder. The dual voice coil design includes two sets of positive and negative terminals, one for each separate coil.
A dual voice coil (DVC) subwoofer enables you to wire your auto subwoofers in either series of parallel. The major difference between wiring in a subwoofer in series versus parallel is the resistance, or ohm load, presented to the amplifier. The higher the impedance an amplifier runs at, the smaller the amount of power flow. Since the prevailing goal in car audio is to maximize your amplifier’s power, dual voice coil subs are great because they enable you to optimize your amplifier’s power.
In series, each speaker you add will increase the impedance load presented to the channel. Wiring in series basically adds up each speaker’s impedance, so the sum of two 4 ohm speakers in series equals 8 ohms of total impedance. In parallel, each speaker you add will decrease the resistance in the channel. The sum of the inverse of each speaker’s impedance equals the total impedance. So two four ohm speakers in parallel is equal to ¼ + ¼ = ½ ohm.
To decide on the wiring configuration, you will need to know your amplifier’s wiring and impedance capacity. Keep in mind that some amps cannot be wired in parallel. You will also need to know your subwoofers’ impedance rating and the number of voice coils.