Incredibly linear frequency response characteristics, extreme high power handling while generating the lowest harmonic distortion of any comparable 18-inch transducer within its application range. The L18P400 uses a fiber loaded cone assembly along with a high excursion triple roll, constant geometry surround. A fully optimized T-pole design generates the minimum amount of flux modulation. The T-pole also features RCF Precision's spaced gap demodulation technology, progressively breaking the voice coil, providing a much smoother transition for the moving mass as it reaches its maximum excursion limits. Forced air venting system.