The PR 4 combines a very unique blend of acoustic energy reflector with unconventional rear loading transmitter. The PR series design concept helps minimizing box coloration at the same time enhancing single driver performance. The main mid/bass driver is a WHT own special (crossoverless) 12" unit mated to the Neo ribbon tweeter. The speaker dimensions are deliberately living-room friendly while the combination of piano-gloss lacquer on the sides, real leather on top and front and exotic Jarrah wood for the scoop will appeal to even jaded interior decorators. A true sensitivity of 102dB/W/m combined with a nominal 9 Ohm impedance welcomes low-power tube amps as well as high-power solid state. Exceptional speed and coherence are made possible by true in-phase operation of both drive units within their respective pass bands. PR4 are also bi-wirable.

Technical details
General: 2 way reflector construction with Jarrah scoop acting as a 18" passive cone.
Drivers:
Woofer: 12" WHT mid/bass (crossover-less) woofer. Paper cone moulded not pressed. Annealed silver ribbons wired directly from woofer to the binding post.
Tweeter: 15mm x 145mm x 0.015mm ribbon enforced sandwich. Tweeter frequency response 1250Hz - 42kHz. Wired with silver ribbons direct - no solder
Frequency response: 30Hz - 42kHz +/-3db
Impedance: 9 Ohm (min. 8 ohm)
Crossover: Woofer: no crossover, Tweeter: 1.25kHz
power: 1W - 500W 102db/m/W
Dimensions
width: 39cm (15.3")
Height: 106cm (41.7")
Depth: 36cm (14.2")
Weight: 56 kg (123 lb) each