Martin Audio SX118+

The Martin Audio SX118+ is a compact, high-performance reflex-loaded subwoofer engineered to deliver powerful low-frequency extension down to 38Hz while maintaining a compact footprint. Featuring an advanced 18-inch long-excursion neodymium driver with a 4-inch aluminium voice coil and waterproof cone, the SX118+ provides exceptional output, efficiency, and bass impact for both touring and installation applications. Its robust plywood enclosure, flexible mounting options, and cardioid deployment capability make it an ideal solution for professional sound reinforcement systems requiring high-performance low-frequency reproduction.

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Key Features

• Compact direct-radiating reflex-loaded subwoofer
• High-performance 18-inch long-excursion LF driver
• Powerful neodymium motor with T-pole and demodulation ring
• 4-inch aluminium voice coil for high power handling
• Waterproof cone for enhanced durability
• Extended low-frequency response down to 31Hz (-10dB)
• High-output capability for touring and installed sound systems
• Omnidirectional or cardioid operation when paired
• Tour-grade birch plywood enclosure
• Available in black or white finish
• Integrated M20 pole-mount socket
• Extensive M10 rigging and mounting points
• Weather-resistant connectivity options
• Front and rear LED status indicators

Technical Specifications

• Type: Compact Direct-Radiating Reflex-Loaded Subwoofer
• Frequency Response: 38Hz – 100Hz (±3dB), -10dB @ 31Hz
• Driver: 18″ (460mm) Long-Excursion Driver
• Voice Coil: 4″ (100mm) Aluminium Voice Coil
• Motor Type: Neodymium Motor with T-Pole and Demodulation Ring
• Cone Type: Waterproof Cone
• Power Handling: 1500W AES, 6000W Peak
• Recommended Amplifiers:
  • iK41
  • iK42
  • iK81 (Bridged for Full Output)
• Sensitivity: 99.5dB
• Maximum SPL:
  • 131dB Continuous
  • 137dB Peak
  • 143dB Peak (Crest Factor 4)
• Nominal Impedance: 8 Ohms
• Dispersion: Omnidirectional or Cardioid (When Paired)
• Enclosure Material: Multi-Laminate Birch Plywood
• Finish: Textured Black or White Paint
• Grille: Black or White Perforated Stainless Steel
• Environmental Rating:
  • IP21
  • MIL-STD-810H Tested
  • ISO 4892-2 Solar Radiation
  • ISO 12944-6 Category C3 Corrosion Resistance
• LED Indicators:
  • Front LED
  • Rear LED (for Cardioid Configurations)
• Connectors:
  • 3 × NLT4MPXX-BAG
  • One Front Input
  • Two Rear Connectors
• Weather Protection:
  • IP54 Seal with Compatible NLT4FX, NLT4FX-BAG or Weatherproof NL4 Plug
• Input Connections (Front): 1+ / 1-
• Input Connections (Rear): 1+ / 1-
• Link Connections (Rear):
  • 1+ / 1- linked to 1+ / 1-
  • 2+ / 2- linked to 2+ / 2-
• Pole Mount: M20 Top-Mounted Thread Plate
• Handles: 2 Side-Mounted Bar Handles
• Mounting Points:
  • 20 × M10 Mounting Points
  • 16 × M8 Inserts for Optional Castors
• Additional Features:
  • Base Skids with Mating Top Channels
• Dimensions (W × H × D): 650 × 603 × 635 mm
• Dimensions with Castors: 650 × 603 × 763 mm
• Weight:
  • 49.2 kg (Without Castors)
  • 52.5 kg (With Castors)