Напольная акустика — Zellaton REFERENCE ULTRA

Made in Munich by Zellaton GmbH, the Reference Ultra is a three-way tower and the middle model of the Ultra series, placed between the Stage Ultra and the Statement Ultra. It shares its enclosure dimensions with the Reference Mk II from the Klassik line but uses the newer Ultra diaphragm in every driver.

Key specs that matter

Its driver set consists of a 33 mm full-cone tweeter, a 180 mm full-cone mid woofer and three 220 mm full-cone woofers. The maker rates the range at 22 Hz to 40 kHz, the nominal impedance at 4 ohm and the sensitivity at 91 dB at 1 W and 1 m. Each cabinet is 131 cm tall, 45 cm wide and 71 cm deep, and the weight is given as about 135 kg per speaker.

Engineering and use context

The Ultra diaphragm is a three-layer sandwich built from shock-absorbing foam with a handmade paper backing. Its surface carries an embossed structure that the company says was inspired by biomimicry, and the pattern is meant to radiate energy directly along the axis of the cone. The combination is designed to raise stiffness while keeping high internal damping, and each cone is damped by hand to reduce partial vibrations. The maker states that the Ultra diaphragm brings together the useful properties of different materials. As with all Zellaton models, the drivers are individually balanced and then tuned inside the finished housing in a time-consuming manual procedure, and membrane production is overseen by co-founder Manuel Podszus. The company follows the approach of a small, fast bass driver rather than one very large cone, which is why the low range is split across three woofers instead of a single big woofer. Its full-cone tweeter design is specified to work far into the ultrasonic range with very little partial vibration, and each one needs days of manual finishing. The Ultra range is offered with a wide choice of customisation for the finish.

Pairing

With its high sensitivity the Reference Ultra needs less amplifier power than its size suggests, but the three woofers and the low nominal impedance still call for an amplifier with stable current delivery into low impedances. Its deep cabinet and overall mass point to a larger dedicated room rather than a 20 m2 space.

Alternatives

The Zellaton Stage Ultra uses the same Ultra drivers in a smaller cabinet with a single woofer.