The WMI Rack 5/4 is a wall-mounted hi-fi equipment rack from Pro-Ject Audio Systems, representing the reissue of one of the company’s most celebrated designs. The original concept dates back to the earliest days of Pro-Ject, when founder Heinz Lichtenegger collaborated with his colleague Heinrich Prohaska and researchers at the Vienna University of Technology to develop a wall console engineered specifically to improve analogue playback performance.
Design Rationale
The underlying principle is mechanical grounding: by mounting hi-fi components on a rigid wall bracket rather than a freestanding floor rack, vibrations from both external sources (such as footsteps or room acoustics) and internal sources (such as stylus tracking) are channelled directly into the high-mass mounting surface of the wall itself. Solid brick or concrete walls provide the ideal mechanical ground, effectively absorbing and dissipating resonances rather than allowing them to feed back into sensitive components.
Frame Construction
The WMI Rack 5/4 is built around a steel frame whose D-shaped circular profile is not merely aesthetic. The rounded geometry is precisely calculated so that any residual vibrations travel the shortest possible path to the wall mounting points, minimising the time any resonance spends within the frame structure. Frame thickness, material, and angular geometry are all derived from research into resonance propagation, ensuring the rack acts as a conduit to the wall rather than a source of stored energy.
Shelves and Adjustability
Four shelves are fabricated from a specially selected, low-mass, stiff wood chosen for its acoustically neutral properties. Each shelf sits on height-adjustable spikes, allowing precise levelling on walls that are not perfectly plumb and enabling fine-tuning of the spacing between components. The 167 mm maximum clearance between shelves accommodates most standard hi-fi separates, and a 50 mm gap between each shelf and the wall provides routing space for interconnects and power cables.
Practical Considerations
The WMI Rack 5/4 holds up to four components, with each shelf rated to support up to 50 kg subject to the wall type and quality of mounting hardware used. Pro-Ject strongly recommends consulting a professional installer to determine the appropriate fixings for your specific wall construction. The rack is finished in White, with the steel frame and wood shelves sharing a consistent light finish that integrates cleanly into contemporary listening rooms.
