Eighteen Sound XD125

Eighteen Sound XD125 is designed for the reproduction of high frequencies in 2 or 3-way systems. In addition, its 25.4 mm (1 ″) reel requires the use of EWAL  (Edge Wound Aluminum Voice Coil) technology. In fact, this driver will provide an unmatched combination of extended linearity and very high efficiency. The main advancement in the XD125 compression driver is a new and innovative diaphragm, made of treated polyethylene. This design maintains the resonant frequency at 1600Hz, extending the frequency response in the central region compared to the previous driver model, the XD120.

The membrane

The design of the diaphragm and the polyester coating allows better control in terms of movement and mechanical stress. Radial ribs increase rigidity by avoiding uncontrolled vibrations in the useful frequency range. The 1 ″ moving coil in aluminum wire, wound on a treated Nomex support, completes the diaphragm assembly. In fact, the treated Nomex, thanks to its physical properties, shows an elongation value with traction greater than 30% compared to Kapton (at the operating working temperature of 200 ° C). This makes it possible to maintain control of the energy transfer on the dome in real working conditions. In addition, Eighteen Sound's patented Nomex trainer is suitable for working in environments with a higher humidity content.

The rephaser

The polypropylene rephaser is the result of a meticulous design process. In fact, its shape ensures the correct acoustic impedance of the dome, reducing distortion levels over a wide range of frequencies. So, the end result is a coherent and uniform wavefront at the entrance of the horn, high thermal stability and mechanical strength. The compact and lightweight ferrite magnet was designed to obtain 16,000 Gauss in the air gap.

The trumpet

The die-cast polyurethane foam horn of the XD125 keeps the dispersion constant at 90 ° (horizontal) x 60 ° (vertical), providing a coherent frequency response on and off axis from 2 kHz to 16 kHz on the horizontal plane and from 2, 50 kHz to 16 kHz in the vertical plane. The directivity of the horn is constant from 2.50 kHz. In addition, the horn is designed to be free of resonances and vibrations, while ensuring maximum resistance to mechanical stress.