Frequency range (-6db points 17.5Hz-25 kHz), Bass loading Sixth-order Butterworth alignment 19 Hz cut-off, frequency response 20 Hz-20kHz +or- 2dB free-field, Dispersion 20 Hz-15kHz Horizontal: +0-3dB over 60 degress of centre window Vertical: +or- 1dB over 10 degress of centre window, 88 dB at 1m for 2.83V, distortion For 95 dB at 1m Second harmonic: <1.5% 20 Hz-100Hz Third harmonic <0.5% 20Hz-100Hz crossover network Fourth-order Butterworth acoustic response crossover frequency 380 Hz and 3 kHz, impedance Nominal 8 ohms (not falling below 4 ohms), drive units One 300 mm high-power polymer cone base One 126 mm Kelvar cone midrange one 26 mm metal dome high frequency, power handling Suitable for amplifiers of 50-600W, dimensions Height: 1008 mm (39-11/16') Width 432 mm (17') Depth 560 mm (22"), weight 50 kg (110 lb)