Floorstanding loudspeakers — Børresen Acoustics Børresen 05

The Børresen 05 is the standard edition of the tallest tower in the 0-series from Børresen Acoustics, owned by Audio Group Denmark. It follows a 2.5-way layout with seven drivers per cabinet, and it is the base on which the Cryo and Silver Supreme editions are built, fitted with copper rings in its motors and metalwork that has not been deep-frozen.

Key specs that matter

Published response covers 25 Hz to 50 kHz, with a sensitivity of 90 dB for one watt, and more than 50 W of amplification is advised. The treble unit is the in-house RP94 ribbon planar tweeter, whose model name reflects its 94 dB efficiency. Each speaker measures 155 cm in height, 30.5 cm in width and 58 cm in depth and weighs 75 kg. The European price was EUR 100,000 per pair, while the North American figure was USD 120,000. The Cryo Edition adds EUR 10,000 to that, and the Silver Supreme Edition reaches EUR 166,670.

Engineering and use context

Driver count sets the 05 apart from the 03, and the impedance is specified as staying above 5 ohm, so the load remains easy for most output stages. A single planar ribbon tweeter works above roughly 2.5 kHz, a pair of bass/midrange units with 11.5 cm cones sits around it, and four larger units with 15.5 cm cones handle the low end. Every cone bonds ultra-thin carbon sheets to both faces of a 4 mm Nomex honeycomb core, which gives low mass with high stiffness. The bass/midrange motors avoid iron completely, using opposing neodymium-52 ring magnets, and their voice coil inductance is quoted at under 0.04 mH. The tweeter has a moving mass of only 0.01 gram. A serial crossover built using coils impregnated under vacuum and foil capacitors of military specification keeps the current through the drivers locked in phase across the transition. Three reflex ports, each with a metal diffuser insert, vent the enclosure, and the base has height-adjustable feet prepared for Darkz decoupling elements.

Pairing

With its high sensitivity the 05 can be driven by modest solid-state power, and Audio Group Denmark has shown it with its own Aavik M-300 mono amplifiers. The heavy, tall cabinet suits a room larger than 20 m2, where the four bass units have space to load.

Alternatives

A more compact choice in this 0-series is the Børresen 03, with one ribbon and four smaller woofers in a shorter cabinet.