Towards the middle of 2013, German Physiks delivered a pair of Unlimited Mk II loudspeakers to the Hi-Fi+ offices. Towards the end of 2015, German Physiks did precisely the same thing, in order to show precisely what had changed in the intervening years. Even though the Unlimited Mk II is a child of the 2010s, German Physiks was prepared to revise one of its most successful designs, but while many brands would be content to call these changes an entirely new version, German Physiks is satisfied with quietly making a better product.
Let’s loop back 31 issues and discuss the Unlimited Mk II itself. Born out of the 2010 ‘Limited II’ (a 100-pair limited run designed to show what the company can do with a lower than usual price tag). The Limited II proved extremely popular, with all 100 selling out fast, so the Unlimited Mk II followed in its wake. A tall, slender, omnidirectional floorstander, like many others in the German Physiks line, the key cost saving exercise in the Unlimited Mk II was making a four-sided enclosure instead of the octagonal cabinet of the next in line HRS-130.
The Unlimited II features the company’s own Dicks Dipole Driver, or ‘DDD’; a carbon fibre driver with a true 360° horizontal dispersion. Based around a late 1970s concept by German engineer Peter Dicks (hence the name), the DDD concept works with the inherent properties of drive units, rather than treating these functions as limitations. A cone will work pistonically at low frequencies, but will shift to bending wave mode and finally fully modal radiation properties as the frequency rises. Rather than try to find ‘work arounds’ to overcome these intrinsic aspects of a loudspeaker, Dicks proposed designing a loudspeaker that utilised these inherent functions of a drive unit, effectively producing a near full-range four-way loudspeaker in one cone.
Those with extremely long memories might also recall the Ohm loudspeaker system, which featured a similar driver designed by the late Lincoln Walsh. This ‘bending wave transducer’ design had the same basic conical section (beautifully described by Dick Olsher in our sister title The Absolute Sound as looking, “like a giant inverted ice cream cone”). The pulsating drive unit was ahead of its time, and way ahead of the materials science of the early 1960s. Fast forward almost 20 years and cone materials like lightweight titanium allowed the bending wave transducer to come of age, and subsequent developments in carbon-fibre meant the DDD unit improved still further.
The resultant design looks unlike most loudspeakers, with a top pod containing the driver’s magnet, voice coil and spider, with the cone itself facing down into the top of the main enclosure (the ‘giant inverted ice cream cone’ coined by Olsher). There isn’t a loudspeaker basket as such, just a series of chrome plated rods to support the top of the drive unit. A more conventional carbon-fibre 200mm down-firing unit sits at the bottom of the cabinet, providing bottom-end reinforcement.