S 21

Touring high performance compact 21″ subwoofer

TransducersLF : 1 x 21″
SPL peak / 1m (measured)139 dB
Weight58.8kg / 129.63lbs
RiggingPole mount
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S 21 is a compact, high-performance passive touring subwoofer, designed to complement our FR-X, ARES8 and ARES12 series in sound reinforcement applications scaling to full stadium shows.

S 21 houses a long excursion 21″ neodymium driver and combines front diffusion, bass reflex, and transmission line design for maximum efficiency and outstanding SPL. Cardio and end fire on every version.

Rental companies favor S 21 as an alternative to industry-standard 2×18” subs, saving half the truck space and around 40% of the weight. The subwoofer can be deployed standalone, stacked or flown, making it a versatile, high-earning hire stock staple.

S 21 is built with pride in Belgium and coated in tough, weather-resistant polyurea to safeguard your investment. The cabinet front is protected by a rigid metal grill, backed by acoustically transparent foam.

We recommend AUDIOFOCUS or Powersoft amplifiers for use with S 21.


  • Powerful bass-reflex T-line design
  • Lightweight and portable
  • Pole mount socket
  • Passive

Technical specifications

DescriptionHigh-power subwoofer
Transducers LF: 1 x 21″
Frequency range (-6dB)28Hz – 100 Hz
SPL peak (1)139 dB
ProcessingDedicated AUDIOFOCUS SCiO and Armonia/Powersoft omni and cardio presets
RiggingPole socket
Connectors2 × 4-point speakON
Nominal Impedance8ohm
Watt AES/peak1700/6800W
Dimensions (H x W x D)590 x 750 x 655 mm
23.22 x 29.52 x 25.78 inches
Weight58.8kg / 129.63lbs
FinishHighly resistant polyurea coating

CabinetHigh grade birch plywood

(1) Peak level measured at 1 m under free field conditions using pink noise with crest factor 5

Gll files for Ease and Easefocus

S 21

Gll • 1.65 Mo • 06/01/2022

S 21 Stack

Gll • 1.78 Mo • 06/01/2022