This advanced subwoofer design incorporates a newly developed, longer four-layer aluminum voice coil. This design improves heat dissipation, increases magnetic gap energy, raises sensitivity, boosts power handling, reduces distortion, and enhances overall performance. The 21DS115 uses a 36 mm long, 4.5" (116 mm) diameter copper clad aluminum wire voice coil, delivers a 1700 watt AES power rating, achieves 99 dB sensitivity, and offers more than 14.0 mm of Xvar, representing a major advancement over comparable models in the B&C lineup.