Floorstanding loudspeakers — Mbl 101 X-Treme MKII

The 101 X-Treme MKII is a four-way, four-tower Radialstrahler loudspeaker system from MBL of Berlin. Two main towers carry the omnidirectional drivers, and two separate towers hold active subwoofers, so the complete setup counts 26 drivers. The price for a pair was quoted at EUR 375,000 in 2026, and USD 433,000 in North America.

Key specs that matter

MBL gives a frequency response of 24 Hz to 40,000 Hz and a nominal impedance of 4 ohm. The crossover points sit at 82 Hz, 600 Hz and 8,350 Hz. Nominal power is 2 x 900 W. Each main tower measures 49.6 cm in width, 185.4 cm in height and 68.7 cm in depth, and each subwoofer tower is 41 x 186 x 67 cm. The whole system weighs 984 kg.

Engineering and use context

In the main towers the radial tweeter, midrange and woofer units are doubled in a mirror array following the D'Appolito arrangement, with one set above and one below. These radial drivers, which give the Radialstrahler name its meaning of radial emitter, radiate over 360 degrees rather than forward from a flat baffle, so the listening position is less tied to a narrow axis. The drivers sit on massive base and top pieces of constrained-layer sandwich construction built from birch, brass and aluminium. Ambient tweeters are added to the array as well. The two subwoofer towers are active and contain twelve 12 inch aluminium sandwich drivers in total, loaded by more than 500 litres of enclosure volume. A built-in parametric equaliser acts on the low-frequency section. Finishes offered are piano black with chrome and piano white with chrome.

Pairing

The system suits medium to large rooms, with MBL naming a range of 35 m2 to 120 m2, so it is not intended for a 20 m2 space. Because the low bass is amplified inside the subwoofer towers, the external amplifiers only have to drive the main towers above the lowest crossover point. With a low nominal load, solid-state stereo or mono amplifiers able to deliver high current are the logical choice, and MBL's own amplifier ranges are designed around the Radialstrahler load. A preamplifier with balanced outputs simplifies feeding both the main amplifiers and the subwoofer electronics.

Alternatives

The MBL 101 E MKII is a four-way Radialstrahler floorstander from the same company with its woofer in a bandpass enclosure, housed in a single 1720 mm tall cabinet weighing 80 kg.