Incredibly linear frequency response characteristics, extreme high power handling while generating the lowest harmonic distortion of any comparable 18-in ch trasducer wtihin its application range. The L18P400 uses a fibre loaded cone assembly along w/a high excursion triple roll,constant geometry surround. A fully optimised T-pole design generate the minimum amount of flux modulation. The T-pole also features RCf Precision's spaced gap demodulation technology, progressively braking the voice coil, providing a much smoother transition for the moving mass as it reachees its maximum excursion limits. Forced air venting system.