The Celestion FTR12-4080HDX 12" woofer/subwoofer features an advanced thermal management system that includes the use of an Inside/Outside voice coil and careful attention to motor ventilation. This system results in reduced power compression caused by increased resistance due to heat build-up; the result is greater reliability and the speaker's ability to maintain maximum SPL during extended hard use. The FTR12-4080HDX's dual-spider design and multi-roll outer suspension combine maximum excursion with ultimate control, resulting in deep, powerful, low-distortion bass output.