What are dual voice coil subwoofers?

Dual voice coil subwoofers are a popular choice among car audio enthusiasts who want more flexibility in wiring their sound systems. While typical subwoofers have a single voice coil, dual voice coil (DVC) subwoofers use two separate voice coils, each with its own connections, mounted on one cylinder, connected to a common cone.

The key difference between single and dual voice coil subwoofers is the multiple wiring options DVC subs offer:

• Parallel: A dual 4-ohm voice coil subwoofer with its coils wired in parallel presents a 2-ohm load to your amplifier. Since an amplifier produces more wattage at a lower impedance, the parallel connection ensures you'll get the most output from your amp. In the same fashion, if you have a stereo amplifier and two DVC subs, wire both subs for 2-ohm impedance (one per channel) for maximum output.

• Series: Series wiring lets you configure multiple woofers to one amplifier at an acceptable impedance. Wire both coils in series for an 8-ohm impedance, and then wire two 8-ohm subs together in parallel for 4-ohm total impedance (perfect for most 2-channel amps bridged to mono operation). Another example: if you have a high-powered 2-channel amplifier, wire four 8-ohm subs per channel (each channel sees a 2-ohm load).

• Independent: You can wire each voice coil to a separate channel of your amplifier, if you prefer not to bridge your amp. Independent wiring is a nice option if you're wiring two DVC subs to a 4-channel amplifier — one voice coil per channel. Just make sure the signal going to each coil is exactly the same, or the differences will cause distortion.

DVCs and high-performance amplifiers

Some amplifiers are designed with an unregulated power supply — these amps are favored by mobile audio competitors for their superior performance. An unregulated amp's power increases dramatically when it sees a lower impedance load. For example, an amplifier that produces 75 watts RMS x 2 channels at 4 ohms would double its power to 150 watts x 2 with a 2-ohm load. DVC subwoofers (particularly the dual 2-ohm models) give you the flexibility to wring every bit of power out of this type of amplifier.

Also, if you choose to add an unregulated amp as a power upgrade to your existing DVC subwoofer system, you can simply rewire your subs for optimum impedance. Remember that most car amps are stable down to 2 ohms in normal operation, and to 4 ohms in bridged mode. It's important to check your amp's manual for its operating parameters before hooking up a DVC sub that's wired for low impedance.

A DVC sub offers the same performance whether it's wired in series or parallel. Its power handling levels, frequency response, and other specifications do not change — the only difference is the impedance presented to the amplifier. As a result, you'll need to use the enclosure that's recommended for your sub, no matter how it's wired.