From Estelon:

The new XB Diamond Mk II is the closest alternative to the X Diamond Mk II, which performs outstandingly in smaller listening spaces. The new XB Diamond Mk II combines the best in sound and design, which is the hallmark of Estelon products.
The XB Diamond Mk II features a 1″ diamond tweeter, along with new cabling and a top-of-the-line crossover, that deliver extended high frequencies for a smooth and a resonant-free acoustic experience. The XB Diamond Mk II will intensify the fidelity through its transparency, precision, and unprecedented detailed reproduction.

Through Estelon’s advanced and innovative engineering concepts, the loudspeakers form a synergy with the room and its acoustics to re-create an emotionally involving listening experience that exposes the soundstage and musical details of the recording, as it was meant to be heard.
The combination of curved cabinet walls and a complex system of interior chambers make the cabinet completely “dead” and non-resonant. Furthermore, the enclosure of each driver system has optimized enclosure geometry to suit specifically for the driver to perform its best. Such a highly advanced and complex cabinet design and construction allows only pure and uninfluenced sound to emanate from the various high-performance driver elements.

Room dimensions and characteristics have a significant effect on the listening experience. The pressure at these frequencies changes equally in every position, similar to pressing on a balloon. In these conditions, it is impossible to localize the exact position of the bass driver. This situation allows the placement of the low-frequency driver to be separate from other drivers.
The Estelon XB Diamond’s woofer is positioned close to the floor so that the woofer couples acoustically with the surface of the floor maximizing its efficiency and output. The placement of the woofer close to the floor assists in bass coherency and a more even distribution of room standing waves. This makes it easier to find a suitable listening position in the room, with fewer compromises in bass accuracy.

In frequencies over 100 Hz, there are numerous sound reflections created between the loudspeakers and the walls, ceiling, floor, and furniture/décor. In these higher than low bass frequencies where the wavelength of the sound is short enough for human hearing to be able to detect where the sound originates and to produce localized peaks and valleys in the room due to standing waves, the placement of the driver in relation to other drives becomes significant.
The drivers that reproduce sounds over 100 Hz (mid-woofer and tweeter) are grouped together and physically placed higher in the cabinets. In this configuration, the reflections from adjacent surfaces are minimized. Furthermore, a high degree of coherency can be achieved with a stable stereo image from high bass notes up to the highest harmonics.

• TYPE: 3-way passive loudspeaker, bass reflex
• DRIVERS:
  Woofer: 220 mm (8.7″) Accuton, ceramic sandwich dome
  Mid-woofer: 158 mm (6.25″) Accuton, ceramic membrane
  Tweeter: 25 mm (1″) Accuton, diamond inverted dome
• INTERNAL WIRING: Kubala-Sosna
• FREQUENCY RESPONSE: 22 – 60 000 Hz
• POWER RATING: 150 W
• NOMINAL IMPEDANCE: 6 Ω (min 3,1 Ω at 51 Hz)
• SENSITIVITY: 87 dB / 2,83 V
• MINIMAL AMPLIFIER POWER: 30 W
• DIMENSIONSHeight:
  1260 mm (49.5″)
  Width: 420 mm (16.5″)
  Depth: 590 mm (23″)
  Net weight: 69 kg (150 lbs.) per piece
• CABINET MATERIAL: Marble based composite
• RECOMMENDED ROOM SIZE: 25-50 m² (270-540 ft²)