L-Acoustics | KS21 - High power compact subwoofer: 1x21''

L-Acoustics | KS21 - High power compact subwoofer: 1x21''

The L-Acoustics KS21 is a compact subwoofer built around a single 21" neodymium driver, designed for audio professionals who need serious low-frequency power in a manageable size. With its exceptional power-to-size ratio, the KS21 is a popular choice for touring, rental and live events, from small shows to large-scale productions.

Powerful, tight low end

The KS21 delivers deep, impactful bass with remarkable clarity. Its bass-reflex enclosure features L-Vents™, laminar ports that reduce port noise and turbulence at high levels while improving low-frequency efficiency. The result is a clean, controlled low end that stays sharp, even when pushed hard.

Standard or cardioid configurations

Using the dedicated presets, multiple KS21 subwoofers can be deployed in standard or cardioid configurations. A cardioid setup reduces low-frequency energy towards the rear, keeping the stage cleaner and giving you more control over coverage in the venue.

Built for the road

• Integrated rigging system for fast, simple flown or stacked deployment
• Premium Baltic birch and beech plywood enclosure
• Coated steel grille with acoustically transparent fabric front
• Four ergonomic handles and corner stops for easy handling and protection
• Weather-resistant, road-ready construction

Part of the L-Acoustics ecosystem

The KS21 is driven and protected exclusively by L-Acoustics amplified controllers using dedicated presets, ensuring consistent performance and seamless integration with your L-Acoustics system.

• Low frequency limit (-10 dB): 29 Hz (KS21_60)
• Maximum SPL: 138 dB (KS21_100)
• Nominal directivity (-6 dB): Standard or cardioid configuration
• Transducers: 1 × 21″ neodymium cone driver
• Acoustical load: Bass-reflex, L-Vents
• Nominal impedance: 8 Ω
• Amplification: LA4X / LA8 / LA12X
• Connectors: 2 × 4-point terminal block with push-in connection
• Rigging and handling: External rigging kits; M6 inserts for rigging plates; M8 inserts for A-U15i; 1 DIN580-compatible M8 threaded insert
• Dimensions (H × W × D): 764 × 571 × 601 mm (30 × 22.5 × 23.7 in)
• Weight (net): 49 kg (108 lb)
• Cabinet: Premium grade Baltic beech and birch plywood
• Front: Coated steel grill; acoustically neutral 3D fabric
• Rigging components: High grade steel with anti-corrosion coating
• Finish: Dark grey brown, Pantone 426 C
• IP rating: IP55