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  • Night clubs
  • Live performances

Key Features

  • Compact, high-performance, transmission line 2x21" infra subwoofer.
  • Dedicated infra subwoofer with low-frequency extension.
  • Cabinet braced internally to eliminate any cabinet resonances.
  • Suitable for use in fixed installation and mobile application.
  • Easy to install.
  • Can retrofit into existing venues.


  • Recessed Handles
  • Perforated grill
  • Metal backplate with Heavy-duty NL 8 connector
  • Reinforced top hat
  • Wooden cabinet
  • Rubber feet under the cabinet
  • Special cups to lock the feet of the kick subwoofer.
  • Inserts to fix castors

Hardware Options

  • CABLE: MIN 6 mm2
  • CONNECTOR: Neoteric NL8

Recommended Amplifier

  • CSC HPA 6402


  • Specifications download

RRI 21s

It extends the frequency response of a system down to 25 Hz and can only be used in ground-stacked configurations or arranged in an infra subwoofer array. The RR 21i cabinet is constructed from marine plywood and has a texture painted finish. A rigid metal grill protects the loudspeaker cabinet drivers, and the side panels incorporate eight handles. It is possible to reposition the Rubber feet fitted on the cabinet's bottom to the cabinet's side panel.

RRI 21s is a transmission line infra subwoofer to provide that extra low-frequency extension. This subwoofer employs a pair of 21" drivers. Designed to reproduce the lowest octave and remove all the kick subwoofer's stress, RRI 21s is perfect for live performances and dance clubs. Crafted and reinforced in 18 mm birch plywood.

For demanding applications, we recommend the use of CSC Maestro MS 26 controller with its EQ and limiter functions preloaded in the controller. RRH 218s, RR 215s, and RR 212s are a perfect match for RRI 21s.