A dual voice coil subwoofer is one that has two coils, or speakers, in one housing. This allows the subwoofer to produce more power and a higher quality sound. If you're looking for a subwoofer that's versatile and can handle a variety of music genres, a 4-Ohm dual voice coil design subwoofer is a great option. A single voice coil is better for bass-heavy music and a dual voice coil is better for a variety of music genres.