The SR-221LF is Theory's largest SR Series manifold subwoofer, built for applications that demand maximum low-frequency output without sacrificing the tight, tuneful character the brand is known for. Dual proprietary 21" 3,600W woofers with 4.5" voice coils operate within a large-format manifold bass-reflex enclosure that, despite its size, is engineered for transport via optional caster kits and a universal dolly board. It supports passive or self-powered operation and is upgradeable to powered configuration via a Theory SR Series amplifier kit. Five 20mm top hats across three surfaces, M10 fly points, and twelve handles provide comprehensive rigging and stacking capability.
- Dual 21" 3,600W low frequency drivers with 4.5" voice coils
- Passive operation requires at least 2 Theory Loudspeaker Controller amp channels
- Requires model-specific Theory-certified DSP loudspeaker processing
- Premium multiply birch plywood enclosure with poly urea paint coating
- 2 large low-turbulence ports
- Twelve horizontal and vertical handles for transport and rigging