The subwoofer shall be a passive, direct-radiating system. It shall feature two 18” (460 mm) low-frequency drivers with 4” (102 mm) voice coils, housed in a robust plywood enclosure with slot ports to enhance efficiency and reduce air noise.
The on-axis frequency response shall be 38 Hz to 100 Hz (±3 dB), with low-frequency extension down to 31 Hz (–10 dB). The subwoofer shall be capable of producing a peak SPL of 136 dB (142 dB with crest factor 4) at 1 metre. Nominal impedance shall be 4 ohms. The system shall require external amplification and processing. For optimal performance, it shall be used in conjunction with a dedicated electronic controller such as a Martin Audio DX series processor, paired with a VIA series amplifier, or with an iKON series combined amplifier and processor.
The enclosure shall be finished in durable black paint and fitted with a perforated, impact-resistant steel grille. It shall include an M20 / 1.4” (35 mm) pole-mount socket for use with full-range loudspeakers and three NL4 connectors, one of which shall be positioned for linking when the Q218 is in a vertical orientation. The cabinet shall also include four ergonomic side handles, M10 flying inserts and rubber feet for both vertical and horizontal operation. Rebate recesses shall be provided for secure horizontal stacking and fittings shall be included for optional castors.
Dimensions (W x H x D) shall be 536 mm x 1206 mm x 690 mm (21.1 in x 47.5 in x 27.2 in). Weight shall be 82.5 kg (181.9 lbs).
The loudspeaker shall be the Martin Audio Q218.