The Optimal Audio Cuboid 3TX is a compact two-way loudspeaker with an integrated 70V/100V transformer, designed for distributed audio systems in commercial installations. Featuring a 3.5-inch LF driver and 0.5-inch PEI dome tweeter with 30W programme power, it delivers clear speech and background music across long cable runs typical of retail, hospitality, and corporate venues. 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.
3.5″ LF driver with 0.5″ PEI dome HF for clear two-way reproduction
Integrated 70V/100V transformer with rotary tap selection
Portrait or landscape mounting orientation
Mounting hardware included in the box
IP54-rated with optional outdoor connector cover (CIPKIT)
Compact enclosure suits discreet installation
Compatible with Optimal Audio SmartAmp DSP-optimised amplification
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 3.
| Model | Cuboid 3TX White |
| SKU | CUBOID3-WTX |
| Speaker Type | Two-Way with 70V/100V Transformer |
| LF Driver | 3.5″ |
| HF Driver | 0.5″ PEI Dome |
| Power Handling | 30W |
| Line Voltage | 70V / 100V |
| Tap Selection | Rotary Switch |
| Ingress Protection | IP54 (with optional connector cover) |
| Mounting | Portrait / Landscape |
| Colour | White |











