Allen & Heath GR4 4-Zone Rackmount Analog Zone Mixer, 1U

Allen & Heath GR4: Simple, Reliable Multi-Zone Commercial Audio

The Allen & Heath GR4 is a 4-zone rackmount analog zone mixer built for background music and paging in bars, restaurants, stores, and other commercial spaces. It is an analog matrix mixer, not a power supply or a DSP box: its job is to route several music and microphone sources to four independent listening zones, each with its own level. In a single 1U chassis it combines four mic inputs, four stereo line sources, and four zone outputs, which covers the everyday needs of a small-to-mid commercial venue without the cost or complexity of a networked processor. Setup is straightforward enough for a venue manager to operate day to day. For the owner who wants dependable, good-sounding zone control they can set and forget, the GR4 is purpose-built.

Four Zones, Independent Source and Level

Each of the GR4's four zones can carry a different source at a different volume, so the dining room, the bar, the patio, and the restrooms can each get the right music at the right level. Zones 1 and 2 are stereo on Phoenix connectors and switchable to mono, while zones 3 and 4 are mono, matching the reality that many commercial speaker circuits are mono distributed lines. Assigning a source and setting a level per zone is done with simple front-panel controls, no software or programming required. That independence is the whole point of a zone mixer: one system, several rooms, each sounding appropriate to its space. It is the difference between piping one feed everywhere and actually managing a venue's sound.

Mic and Line Inputs for Music and Paging

The GR4 provides four microphone inputs on rear Phoenix connectors, with Mic 1 also selectable from a front-panel XLR for a quick paging or announcement mic. Alongside them, four pairs of stereo RCA inputs accept music players, media sources, and streaming boxes, giving the venue several selectable programs. Having both mic and line sources in one unit means a staff member can duck the music and make an announcement to a zone from the same mixer that plays the background music. This combination of paging and program in a compact box is exactly what commercial installs need. It keeps the whole front-of-house audio chain in one place.

Zone Outputs That Match Real Installs

Output-side, the GR4 offers two stereo zone outputs on Phoenix connectors, each switchable to mono, plus two dedicated mono zone outputs, feeding a mix of stereo and mono amplifier or powered-speaker circuits. Phoenix (Euroblock) connectors are the install standard because they lock in place and terminate cleanly to structured wiring, unlike consumer plugs that can pull loose. Being able to switch a stereo output to mono lets the same unit serve a stereo bar area and a mono ceiling-speaker circuit from adjacent zones. That output flexibility is what makes one GR4 fit a wide range of venue layouts. It is engineered around how commercial audio is actually wired.

Built-In Power and Install-Ready Design

The GR4 runs on an internal universal power supply accepting 100-240V at 50/60Hz and drawing roughly 15 watts, so there is no external adapter to lose or fail. A front-panel mains isolation switch and an operating range of 41-95 degrees F (5-35 C) suit it to permanent rack life in an equipment closet. Housing everything in a single 1U 19-inch chassis keeps a commercial rack tidy and leaves room for amplifiers and source gear. An internal supply also means one IEC cable is the only mains connection, simplifying the install. These are the practical details that make a mixer dependable over years of continuous operation.

Where the GR4 Belongs

The GR4 is made for fixed-install commercial audio: multi-zone background music distribution, restaurant and bar paging, and retail sound where several areas need independent control. It suits venues that want professional zone management without stepping up to a networked DSP matrix and its programming overhead. Reviewers describe it as a clean, simple install mixer that reliably handles zone control and represents good value for commercial audio. For system integrators, it is a fast, predictable install; for venue owners, it is an approachable box they can actually run. When the job is background music and paging across a handful of rooms, the GR4 is the right-sized tool.