Напольная акустика — Zellaton REFERENCE Mk II

Zellaton GmbH hand-builds the Reference Mk II in Munich as a three-way tower belonging to the Klassik series together with the Legacy, the Stage and the Statement. Its list price was quoted at USD 150,000 per pair. Every driver in it is made by hand using the full-cone sandwich technology patented by Dr. Emil Podszus in June 1930.

Key specs that matter

There are five drive units per side. A 40 mm full-cone tweeter sits above a 180 mm mid woofer, and three 220 mm woofers handle the low bass. The mid woofer covers roughly 250 Hz to 6.5 kHz. Zellaton lists the frequency range as 22 Hz to 40 kHz, the nominal impedance as 4 ohm and the sensitivity as 90 dB/1W/m, with a suggested amplifier power of 50 W to 600 W per channel. The enclosure stands 131 cm high, 45 cm wide and 71 cm deep, and one speaker weighs about 135 kg.

Engineering and use context

Each diaphragm combines an aluminium film only 0.006 mm thick, a layer of aerated foam and a treated paper backing. The tweeter cone weighs about 0.16 g. Magnet systems of pure iron were optimised by computer, and the tweeter motor reaches a flux density of 20,000 gauss. Voice coil formers are made of titanium film. In the crossover, capacitors, coils and resistors all come from the Duelund Coherent Audio range, and internal wiring is by Schnerzinger. The cabinet is built up from several layers of wood with wall thickness varying between 34 and 50 mm, braced by an internal matrix, and its rear is largely open from top to bottom rather than sealed. Manuel Podszus, the grandson of the inventor, produces the cones himself, and a single cone takes several weeks to complete. After assembly, each driver is balanced and tuned individually inside its housing, a step the company compares to the way instruments are finished. The company describes its approach as favouring several small, fast bass cones over one very large diaphragm, which explains the three woofers.

Pairing

The wide recommended power window means the Reference Mk II works with a moderately powered amplifier, yet the three woofers and the low impedance favour a transistor amplifier with generous current reserves when the speakers are driven hard. The open-backed cabinet needs free space behind it, so it fits larger rooms better than a compact 20 m2 space.

Alternatives

The Zellaton Reference Ultra keeps the same cabinet size and driver layout but uses the newer Ultra diaphragm with a smaller 33 mm tweeter.