The HD125 1 inch exit HF unit has been designed as the natural evolution of the industry standard HD120 compression driver. It delivers an unmatched combination of extended linear frequency response and very high efficiency.
The HD125 diaphragm assembly is made in proprietary treated polyethylene material. This design maintains the minimum resonance frequency point value at 1600 Hz, extending the frequency response in the mid region when compared to HD120 compression driver.
The design of diaphragm and its surround in polyester material allow a best movement and stress control; the special radial ribs increase stiffness avoiding uncontrolled vibration modes in the usable frequency range.
An edge-wound aluminum voice coil, wounded on proprietary treated Nomex, completes diaphragm assembly. Thanks to its physical properties, the voice coil former shows 30% higher value of tensile elongation at working operative temperature (200°C) when compared to Kapton. This plus is capable to keep properly energy transfer control to the dome in real working conditions. Moreover, this particular former material is suitable to work also in higher moisture contents environments.
The polypropylene phase plug is the result of a meticulous design exercise. Its shape assures the correct acoustic impedance of the radiating dome, reducing distortion levels across a very wide frequency range. At the end, it results in a smooth coherent wavefront in the horn entrance, high thermal stability and manufacturing consistency.
The HD125 compact size and lightweight ceramic magnet assembly has been designed to obtain 16 KGauss in the gap.