The amplified tubes come in dual and single coils as well as the passives. But in the amplified versions there really no need to know whether the woofer is dual or single. Now in the passive versions there may be a need to know. And that need to know needs to be addressed first by how much power a person is going to be sending to the sub and other important things, like what type of music you listen too, what type of vehicle it is going to be installed in.
BAZOOKA MOBILE AUDIO
Technical Support / R & D