B&C 21DS115-4 21" Professional Neodymium Subwoofer 4 Ohm
99 dB efficiency to ensure high output even with modest amplification
Double silicone spider keeps excursion linear even beyond rated Xmax
Neodymium magnet allows a very high force factor without excess weight
4.5" four layer CCA voice coil allows high power handling and Bl
Aluminum shorting ring help control the voice coil for lower distortion
