The SX118+ is a compact, high‑performance subwoofer that extends the system’s low‑frequency operating range to 38 Hz and delivers impressive output for such a compact enclosure.

It features a long‑excursion 18 in (460 mm) driver with a 4 in (100 mm) voice coil, a water‑resistant cone and a triple‑roll surround in a compact reflex enclosure. The driver design maximises output while minimising power compression and distortion. The four reflex ports have a large frontal area to reduce turbulent air noise at very high levels and the internal port geometry promotes laminar airflow.

The enclosure is built from multi‑laminate birch ply, finished with a durable polyurethane coating and fitted with a stainless‑steel grille, twin grab handles, skids, M10 mounting points (with internal brackets) for installation and a threaded pole socket for pole‑mounting point‑source loudspeakers. Cabinet wheels and a transit cover are available as optional accessories.

Compared with the SX118, the SX118+ (Q2 2026) is an all‑new design with enhanced performance and features. It is slightly larger, so it uses a new transit cover, and it includes new drivers and an improved cabinet.

The SX118+ adds a third NL4 input connector on the front to improve cabling for subwoofers used in cardioid configurations. For outdoor use, you no longer need a WRKIT, but you must seal all three NL4 sockets. Use the correct cable connectors (NLT4FX or NLT4FX‑BAG) for connected sockets and install a Martin Audio weatherproof NL4 sealing plug in any unused socket.

The SX118+ has two LED indicators, one on the front and one on the back, which you can illuminate via Vu‑Net software to identify each enclosure on the circuit. The rear LED is intended for use in cardioid setups.

Compact, direct radiating reflex-loaded subwoofer
FREQUENCY RESPONSE (1) 38Hz – 100Hz ±3dB, -10dB @ 31Hz
DRIVER 18 in (460 mm) long‑excursion driver with 4 in (100 mm) aluminium voice coil, neodymium motor with T‑pole and demodulation ring, waterproof cone
RATED POWER (2) 1500W AES, 6000W peak
RECOMMENDED AMPLIFIER iK41, iK42, iK81, bridged for full output For details, see SX118+ User Guide
SENSITIVITY (3) 99.5 dB
MAXIMUM SPL (2, 3) 131dB continuous, 137dB peak
143dB peak with crest factor 4 NOMINAL IMPEDANCE 8 ohms
DISPERSION (-6dB) Omni-directional or cardioid when paired
ENCLOSURE Multi-laminate birch ply
FINISH Textured black or white paint
PROTECTIVE GRILLE Black or white perforated stainless steel
ENVIRONMENTAL TESTING (4) IP rating IP21
MIL-STD-810H
ISO 4892-2 Solar Radiation
ISO 12944-6 Category C3 Corrosion resistance
LED INDICATORS Two LEDs: one front, one rear (rear LED for cardioid subs)
CONNECTORS 3 x NLT4MPXX-BAG (one front, two rear)
IP54 weather‑resistant seal with NLT4FX, NLT4FX‑BAG or weatherproof NL4 sealing plug
PIN CONNECTIONS (INPUT ON FRONT) 1+/1-
PIN CONNECTIONS (INPUT ON REAR) 1+/1-
PIN CONNECTIONS (LINK ON REAR) 1+/1- linked to 1+/1- 2+/2- linked to 2+/2-
FITTINGS Two skids on base, with mating channels on top M20 top-mounted thread plate for pole mounting 20 x M10 mounting points, 5 on top, 5 on bottom, 4 on left, 4 on right, 2 on back
2 x bar handles, one on each side
16 x M8 inserts for optional castors
DIMENSIONS (INCL SKIDS) (W) 650 mm x (H) 603 mm x (D) 634 mm (762 mm with castors)
(W) 25.6 in x (H) 23.7 in x (D) 25.0 in (30.0 in with castors)
WEIGHT 49.2 kg (109 lbs), 52.5 kg (116 lbs) with castors
ACCESSORIES Pack of four castors WHEELKIT
M10 eye bolt HTKCT06
Weatherproof NL4 sealing

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