The Ex Machina Poseidon is a compact passive subwoofer pair designed specifically to extend the low-frequency performance of the Selene monitoring system. Powered and controlled by Selene’s EXCore amplifier and DSP, Poseidon transforms the two-way Selene monitors into a coordinated three-way reference system. This listing includes two Poseidon subwoofers; Selene monitors and the required EXCore electronics are not included.
 
Unlike a conventional standalone subwoofer, Poseidon is developed as part of a complete monitoring architecture. It contains no internal amplification or DSP. Power, crossover processing, time alignment and system calibration are handled by the compatible Selene EXCore unit, allowing the monitors and subwoofers to operate together without an additional external amplifier or separate bass-management processor.
 
Each enclosure houses a custom 16 cm Epique MMAG low-frequency driver with 14.7 mm of linear excursion in each direction. This high-excursion design provides substantial bass capability from a cabinet measuring approximately 16.5 cm across. Poseidon is particularly useful where desktop space, room layout or installation constraints make larger conventional subwoofers impractical.
Integration with Selene uses a zero-phase LR4 digital crossover at 150 Hz. The coordinated processing is designed to maintain phase coherence through the transition between the subwoofers and coaxial monitors, supporting clear transients and a consistent tonal balance. This makes Poseidon a purposeful extension of the monitoring system rather than an independently adjusted bass source.
 
With Poseidon added, the complete Selene system provides a frequency response within ±1.5 dB from 50 Hz to 30 kHz, with a −6 dB low-frequency extension at 35 Hz. The manufacturer specifies continuous low-frequency output of 98 dB at 50 Hz at one metre. These are integrated Selene + Poseidon system figures, not a standalone full-range specification for the passive subwoofers.
The additional low-frequency capability supports more informed decisions about kick drums, bass instruments, low-frequency effects and the tonal foundation of a mix. Poseidon is suited to compact production rooms, editing suites, smaller stereo monitoring setups and compatible immersive installations where accurate integration matters as much as bass extension.
Because the crossover and calibration are managed by EXCore, the system avoids the need to manually align an unrelated subwoofer’s gain, crossover and phase controls. Firmware and calibration updates applied to the compatible EXCore platform also support the integrated monitoring system. Physical placement remains important: room boundaries, listening position and room modes still influence the bass heard at the workstation.
At 6.4 kg per enclosure, Poseidon offers a compact but substantial low-frequency solution. Its small footprint allows flexible placement, although appropriate support and a considered room-acoustic setup remain essential. It is not a general-purpose passive subwoofer for connection to an arbitrary amplifier or monitor system.
 
Poseidon is primarily intended for professional monitoring, but a complete Selene + Poseidon system can also serve demanding stereo listening applications. For either use, the key advantage is a unified architecture in which the drivers, amplification and digital processing are designed to work together.
 
This product includes one pair of Poseidon passive subwoofers only. A compatible Selene monitoring system with EXCore amplification and processing is required for operation.