German Physiks Unlimited Black

About German Physiks Unlimited Black

• Lincoln Walsh isn’t exactly a household name in audiophile circles, but he literally turned driver design on its head in the early 1960s with his revolutionary bending-wave transducer.
• The Walsh driver looked like a giant inverted ice cream cone, terminated at the wide end and driven by a voice coil at the narrow one so that that sound was only radiated from its convex side.
• The cone was made thin enough so that its mode of operation transitioned from being piston-like in the bass range to bending wave in the lower midrange. Imagine vibrational waves rippling down the cone at a speed exceeding that of the speed of sound in air.
• By judicious choice of materials and variation of the cone’s stiffness profile over its length Walsh was able to achieve a coherent propagated wavefront perpendicular to the cone axis. Sonically the cone behaved much like a pulsating cylinder with all frequencies in phase with the input signal.
• Two other important benefits ensued from this design: wide-range operation from a single driver and an omnidirectional radiation pattern approximating that formed by an ideal pulsating sphere.
• The conceptual beauty of a bending-wave transducer resides in the fact that it exploits the non-rigidity of the diaphragm material, working with it rather than fighting it.
• Walsh experimented with several cone materials and obtained excellent results using a 0.002-inch thick aluminium sheet formed to give a 6-inch diameter at the large end.