The TRx2121 is a compact high Q sub-subwoofer design to add extended ultra-low frequencies to any system. Effective for both permanent and portable applications, coupled with the TRx3210 Line array elements provides very powerful extended full range system. The TRx2121 features added foot holes for stacking up to four and dual pole mounts for suspending up to two TR3210s. And third centered pole mount for a TRX12 or TRX115.

The TRx2121 is our finest single 21-inch Subsubwoofer system. The high power, larger format 21-inch woofer features a 4-inch voice coil with high peak power capacity. The box is designed with four large corner located ports producing a coherent sub frequency output vertically and horizontally. This makes the idea low frequency coupling in multi box clusters both in the horizontal and vertical directions.

The TRX2121 features foot locating holes on top for stacking another TRx2121 and for stacking up to 4 TRx3210 line array elements without hardware. Three top pole mounts feature 16" spaced dual pole system for suspending two TRx3210 speakers, and a single centered pole mount for suspending a TRx115 or TRx12.

The enclosure is constructed of CNC machined 13-Ply Premium Russian Baltic Birch with heavy gauge steel powder coated front grills. The crossover includes 4 pin NL4 Speakon connectors mounted on FR4 double sided circuit boards for solid construction and durability.

Applications Include:

Theme parks
House of worship and concert halls
Medium-to-large theaters and clubs
Outdoor concerts and street festivals

Made in the USA.


  • System Type: 21-inch Sub, bass-reflex
  • Frequency Response: 20 Hz - 1.5K Hz (-10DB); 30 Hz - 1k Hz (-3 dB)
  • Coverage Pattern: Omni
  • Crossover: none internal
  • Crossover Frequency: recommended 80-120 Hz
  • Power (Full Range): 1000W Continuous / 2000W Program / 4000W Peak
  • Recommended Amplifier Power: 1100W - 2400W
  • Sensitivity (1w @ 1m): 97dB
  • Maximum SPL: 127dB Cont/ 133dB Peak
  • LF Driver: 21-inch, 4-inch VC, woofer
  • Nominal Impedance Full Range: 4 ohms


  • 13-Ply Russian Baltic Birch
  • Suspension/Mounting: Top: 3 x 1-3/8-inch Pole Mount Cups, Foot receivers for TRx3210
  • Finish: Black DuraTex™
  • Transport: 2 Recessed Handles
  • Grill: Black powder coated steel, Acoustically Transparent Foam Backing
  • Connectors: Two NL-4 Neutrik Speakon
  • Dimensions: 23.5" high x 23.5" wide x 23.5" deep (600mm x 600mm x 600mm)
  • Net Weight: 80 lb (37 kg)

Made in San Diego, California