The QI 125.4 is a compact four-channel installation amplifier that forms the foundation of QUAD Industrial fixed audio systems. Purpose-designed for professional installations, QI 125.4 combines a small physical footprint with the flexibility and control required for modern commercial environments.

Housed in a slim half-rack, 1U chassis, QI 125.4 is easy to deploy in equipment racks, cupboards, under desks or wall-mounted locations where space is limited. It delivers exceptional versatility, offering four channels of low-impedance output or two high-impedance 70 V / 100 V outputs, allowing a single amplifier to support both Lo-Z and Hi-Z loudspeaker systems.

Automatic power sharing intelligently reallocates available power between channel pairs, ensuring consistent headroom and reliable performance as programme demands change across zones. This makes QI 125.4 ideally suited to retail, hospitality, corporate and leisure installations.

At the heart of the platform is QI CORE, our browser-based control software. Through a clear, installer-friendly interface, users can configure inputs, zones, DSP, routing and power management quickly and efficiently. The amplifier also includes internal speaker presets for all our loudspeakers, enabling faster commissioning and predictable, optimised system performance.

Compact, versatile and software-driven, QI 125.4 defines the core building block of QUAD Industrial fixed installation systems.