The hd Qi series is a modular, flexible hardware and software solution for the operation of Harmonic Design loudspeaker systems. The 2U, 19″ rack hardware includes four balanced inputs and up to four power outputs, which can be processed thanks to a high-performance DSP with IIR and FIR filter technology. The associated hd LevelZ user software provides clear access to all parameters through a Windows-based computer or directly on the amplifier via the 3.2″ LCD display with navigation buttons.

2- or 4-channel Class-D amplifiers provide 500W for each power output. They are designed to meet the highest audio quality and reliability requirements in fixed installation projects and mobile applications. Due to the extreme efficiency, the heat generation is absolutely minimized compared to conventional analogue amplifiers. The power amp needs less cooling and works permanently in the safe area. An intelligent temperature management system ensures the lowest possible noise emission and activates the fans only when required by the operating situation. Always-reliable operation is ensured by up to two independent switched-mode power supplies with Power Factor Correction (PFC) that deliver full performance at all times, even in adverse network conditions, such as undervoltage or overvoltage, thanks to their universal operating range of 85V to 265V and are therefore far superior to conventional power supplies.