The HD1050 one inch exit high frequency compression driver has been designed for use in high quality audio systems. Equipped with Eighteen Sound proprietary Phase Plug architecture, the HD1050 has been designed to give high level manufacturing consistency and smooth coherent wave front at the horn entrance across the whole working frequency range. The phase plug with its short openings and high flare rate value assures low distortion and demonstrates remarkable improvements in mid-high frequency reproduction. The diaphragm assembly is composed of a titanium dome sandwiched to a proprietary treated polyester suspension unit. It has been designed to maintain low resonance, lowering the minimum crossover point value at 1,4kHz. An edge-wound aluminum voice coil, wound on proprietary treated Nomex, completes the diaphragm assembly. Thanks to its physical properties, the proprietary treated Nomex former has a 30% higher value of tensile elongation at a working operative temperature (200°C) when compared to Kapton. This feature enables proper energy transfer control from the voice coil to the dome in real working conditions. Moreover, this proprietary former material is also suitable to for use in higher moisture content environments. The HD1050 powerful ceramic magnet assembly has been designed to obtain 16 KGauss in the gap and within a compact ferrite motor structure.