Bookshelf Speakers — Børresen Acoustics Børresen M1

The M1 is a compact two-driver monitor made by Børresen Acoustics of Denmark that packs the M-series technology of the company's large floorstanders into a compact cabinet. It sells for about USD 105,000 per pair, stand included, which places it far above the Z and X ranges in the same brand catalogue.

Key specs that matter

One Børresen RP94 planar ribbon tweeter works above roughly 2.5 kHz, and below that point a single 4.5-inch IronFree5 Zirconium SSE bass and midrange unit covers the rest of the band. Børresen rates the pair at 40 Hz to 50 kHz within 3 dB, 87 dB at 1 W and 6 ohm, and suggests 50 W of amplification. The cabinet measures 36.8 x 20.0 x 44.0 cm and weighs 14.1 kg.

Engineering and use context

The M1 woofer cone is a laminate of four skins - two layers of spread tow carbon fibre around an aramid honeycomb spacer, plus a titanium skin carrying an Ansuz Supreme coating. Its patented iron-free motor has inductance about twelve times lower than a conventional iron-based driver, and here the pole rings are handcrafted in silver instead of the copper used in cheaper Børresen models. Every metal part is cooled to around -196°C during a three-day cryogenic cycle, which the maker says lifts conductivity by 6-8% and relieves residual stress. Its RP94 ribbon is sealed at the back with a moving mass of 0.01 g, 94 dB efficiency and no transformer. The crossover is serial rather than parallel, built with paper-insulated foil coils impregnated under vacuum, capacitors of the stacked foil type to military specification, with metal strip resistors for attenuation. Internal wiring is Ansuz Gold Signature, and the boards carry active square Tesla coils, third-generation analog dither and anti-aerial resonance coils aimed at RF noise. The enclosure evolves the Børresen 01 with extra bracing and 5 mm block-milled pressed wood structures, finished in black piano lacquer and with matched terminal pairs serving tweeter and woofer independently. The matching stand pairs a titanium-laminated top plate with a column and feet of natural based composite material and three built-in Ansuz Darkz Z2S zirconium decouplers.

Pairing

The split terminals allow bi-wiring, and the benign load lets a good amplifier of moderate output, transistor or tube, drive it. Owners who already run Aavik amplification and Ansuz wiring, both part of Audio Group Denmark, get a system built around shared noise-control ideas.

Alternatives

The Børresen X1 is a far cheaper stand-mount made by the same company that is likewise built around a small cone driver and a ribbon tweeter.