SX SeriesInstalled SoundLive Sound


2 x 18" Passive Hybrid® Horn/Reflex Subwoofer

SXH218 | Hybrid® Horn/Reflex Subwoofer
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The SXH218 is the ultimate in subwoofer performance capable of producing 148dB peak output at 1m. It is the ideal partner for both WPS, WPC and WPL arrays where maximum low frequency output is required as well as a standalone solution for premium permanent installations such as nightclubs.


  • Ultra-high output ground-stacked subwoofer
  • Hybrid® horn/reflex loading for maximum acoustic efficiency and low frequency extension
  • Dual long-excursion 18” (460mm)/4.5” (115mm) voice coil neodymium drivers
  • Forward or rear-facing operation


  • Outdoor festivals
  • Stadiums, arenas and theatres
  • Concert halls
  • Nightclubs
  • Outdoor restaurant, bar and hotel entertainment areas
  • Concourses and Theme Parks

Its Hybrid® horn/reflex loading combines the acoustic efficiency and impact of bass horn technology with the low frequency extension of a reflex design, enabling it to produce significantly higher output levels than a traditional reflex-loaded subwoofer. With an operating range of 32-150Hz + 3dB, it features dual long-excursion 18” (460mm)/4.5” (115mm) voice coil neodymium drivers, with water resistant cones and triple roll surrounds.

Also available is the SXHF218, a version of the SXH218 with flying hardware. It can be incorporated at the top of a WPL array, or more commonly flown as a separate array alongside. Like the ground-stack version, a combination of forward and rear-facing enclosures can be configured with specific directional properties.

Both the SXH218 and SXHF218 can be powered by either a single channel of a Martin Audio iK42 4-channel amplifier, or a bridged pair if maximum output is required. Its connector sockets are wired so that one four-core cable from the amplifier will power two subwoofers. Subwoofer settings are determined by a pre-determined parameter set in Vu-Net when used in conjunction with iK42, or Settings are available from the Martin Audio website when used with alternative amplifiers.

By adding the input board cover accessory, the subwoofer is fully weather resistant and suitable for permanent outdoor usage.

User guide Brochure Datasheet Settings [v1.9]
TYPEHybrid® horn/reflex subwoofer
FREQUENCY RESPONSE (1) 32Hz – 150Hz ±3dB, -10dB @ 27Hz
DRIVER 2 x 18” (460mm)/4.5” (115mm) voice coil, long excursion, neodymium magnet, waterproof cone
RATED POWER (2) 3000W AES, 12000W peak
MAXIMUM SPL (9) 148dB peak
DISPERSION (-6dB) Omnidirectional/or Cardioid (paired)
ENCLOSUREMulti-laminate birch/poplar ply
FINISHDurable Polyurea Coating
PROTECTIVE GRILLEBlack perforated Zintec
PINS CONNECTIONS (LINK) Refer to SXH218 datasheet or Input panel diagram for linking options
  • Two skids on base, with mating channels on top
  • Four rear-mounted 100mm (4in) castors
  • 6 x bar handles, 3 on each side
  • 4 x fittings for optional transit cover
  • (W) 1112mm x (H) 609mm x (D) 1023mm (1151mm incl. castors)
  • (W) 43.8in x (H) 24in x (D) 40.3in (45.3in incl. castors)
WEIGHT116kg (256lbs), with castors 120kg (265lbs)
Architectural Specs
Martin Audio SXH218

The loudspeaker shall be a subwoofer consisting of two 18”/4.5” voice coil, long-excursion, low frequency transducers in a hybrid horn/bass reflex configuration. The on-axis frequency response shall be 32Hz-150kHz +/- 3dB and the loudspeaker shall produce a maximum SPL of 148dB peak calculated at 1 metre.

Power handling shall be 3000W AES, 12000W peak. Rated impedance shall be 4 ohms. The rear connector panel shall be fitted with two NL4 type connectors and the loudspeaker shall be operated in conjunction with a dedicated controller amplifier.

The loudspeaker shall be capable of forward and rear-facing operation to enable the construction of ground-stacked subwoofer arrays.

The loudspeaker enclosure shall be constructed from multi-laminate plywood with a textured black polyurea coating. The drivers shall be protected by a perforated steel grille and the enclosure shall be fitted with bar handles and skids.

Dimensions including skids, excluding castors (W x H x D) shall be 1112mm x 609mm x 1023mm (43.8in x 24in x 40.3in). Dimensions including skids and castors (W x H x D) shall be 1112mm x 609mm x 1151mm (43.8in x 23.9in x 45.3in). Weight shall be 120kg (264lbs).

The loudspeaker shall be the Martin Audio SXH218.

Available in this Series

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