The Optimal Audio Cuboid 5TX is a two-way loudspeaker with an integrated 70V/100V transformer, designed for distributed commercial audio systems. Featuring a 5.25-inch LF driver and 0.75-inch silk dome tweeter with 50W programme power, it delivers clear, full-range sound across long cable runs in bars, restaurants, hotels, and retail environments. Also available in black.
This TX model includes an integrated 70V/100V line transformer with rotary switch tap selection, allowing you to set the power draw per speaker across a distributed audio system. This makes it straightforward to balance coverage across zones with long cable runs, using a single amplifier channel to drive multiple speakers in parallel.
5.25″ LF driver with 0.75″ silk dome HF for smooth, natural reproduction
Integrated 70V/100V transformer with rotary tap selection
50W programme power for mid-sized commercial spaces
Portrait or landscape mounting orientation
IP54-rated with optional outdoor connector cover (CIPKIT)
Compatible with Optimal Audio SmartAmp DSP-optimised amplification
Works with Zone controllers, ZonePad wall panels, and WebApp
White finish blends with light interiors and ceilings
The optional CIPKIT connector cover is required to achieve the full IP54 rating for outdoor or exposed installations. For low-impedance installations not requiring a transformer, see the standard Cuboid 5.
| Model | Cuboid 5TX White |
| SKU | CUBOID5-WTX |
| Speaker Type | Two-Way with 70V/100V Transformer |
| LF Driver | 5.25″ |
| HF Driver | 0.75″ Silk Dome |
| Power Handling | 50W |
| Line Voltage | 70V / 100V |
| Tap Selection | Rotary Switch |
| Ingress Protection | IP54 (with optional connector cover) |
| Mounting | Portrait / Landscape |
| Colour | White |











