HK Audio L SUB 4000 - 18” Passive PA Subwoofer with Multi-Layer Birch Enclosure

HK Audio L SUB 4000 – 18” Passive PA Subwoofer with Multi-Layer Birch Enclosure

The HK Audio L SUB 4000 is a passive subwoofer system designed to provide real low-frequency pressure and extension in professional PA setups. Its 18” speaker works in a high-rigidity multi-layer birch enclosure, achieving a response that goes down to 31 Hz (-10 dB) and a maximum SPL of 137 dB (peak, 10% THD) . With 1200 W RMS of power handling, a sensitivity of 106 dB (1W/1m) and a nominal impedance of 4 Ω , it integrates optimally with HK Audio LINEAR 5 systems and the L SUB 2000 subwoofer to create stacks or arrays with punch, headroom and control.

The patch panel features two NL4 Speakon connectors with switchable pin assignments ( 1+/1- or 2+/2- ) for easy parallel cabling, bi-amping from shared racks, or stage feedthroughs. Mounting options include two M20 sockets for satellite bars or dual-bar solutions, and eight handles for easy loading and unloading on the road or for rentals. A metal grille with black acoustic foam protects the driver from impacts and dust, while the black acrylic enamel finish provides durability. The 91 x 51 x 81 cm (36 x 20 x 32 in) dimensions and 57.1 kg (122 lb) weight balance acoustic volume with portability.

Main features

• Transducer: 1 × 18” high performance.
• Type: Passive subwoofer for professional sound reinforcement.
• Frequency response: 39 Hz – X-Over (±3 dB); 31 Hz – X-Over (−10 dB).
• Power Handling: 1200 W RMS.
• Max SPL (peak at 10% THD): 137 dB.
• Sensitivity: 106 dB (1W/1m).
• Nominal impedance: 4 Ω.
• Connections: 2 × Speakon NL4 with switchable assignment 1+/1− or 2+/2−.
• Mounting: 2 × M20 sockets for satellite bars; 8 integrated handles.
• Construction: Multi-layer birch enclosure with metal grille and black acoustic foam.
• Dimensions (W × H × D): 91 × 51 × 81 cm.
• Weight: 57.1 kg.
• Finish: black acrylic enamel.
• Recommended compatibility: HK Audio LINEAR 5 systems and L SUB 2000 subwoofer.

Product benefits

• Deep, punchy bass: extension down to 31 Hz for electronic, rock, live music and AV applications requiring impact and control.
• High output level: 1200 W RMS and 137 dB peak to cover medium and large stages with fewer units.
• Easy integration: Pin switching on NL4 for clean wiring with tops, shared racks, and parallel configurations.
• Versatile mounting: dual M20 socket for satellite bars and clustering options on subs.
• Touring Durability: Multi-ply birch construction, metal grille, and durable finish.

Use cases

• Stacks with LINEAR 5 for bands, DJs and corporate events.
• Arrangements with L SUB 2000 as additional bass support.
• Fixed installations in halls, clubs and auditoriums that require uniform low frequency pressure.

Frequently Asked Questions

• Does it need external amplification? Yes, it's a 4 Ω passive subwoofer; use a suitable power amp and matching processing/crossover.
• Can I connect tops from the same wiring harness? Switchable pin assignments (1+/1- or 2+/2-) make it easy to route independent paths from a single Speakon connector (depending on system configuration).
• Can a satellite be mounted on top? Yes, thanks to the two M20 sockets, you can install speaker bars for compatible tops.

Description for projects

18” passive subwoofer with multi-layer birch enclosure; response 39 Hz – X-Over (±3 dB) / 31 Hz – X-Over (−10 dB); power 1200 W RMS; max. SPL 137 dB (peak at 10% THD); sensitivity 106 dB (1 W/1 m); impedance 4 Ω; connections 2 × Speakon NL4 with switchable 1+/1− or 2+/2− assignment; 2 × M20 sockets; 8 handles; metal grille with acoustic foam; dimensions 91 × 51 × 81 cm; weight 57.1 kg; black acrylic enamel finish; recommended for combination with LINEAR 5 and L SUB 2000.