The RCF SUB 18-AS is a portable high-power, 18” active subwoofer, engineered for live sound applications that demand deep, controlled low-frequency performance. Driven by a 2200W Class-D amplifier, it delivers sound-pressure levels up to 135 dB with exceptional headroom, making it an ideal complement to 10”, 12”, or 15” full-range loudspeakers in small to midsized venues and mobile systems. With a 35 Hz to 400 Hz frequency response and advanced Bass Motion Control processing, the SUB 18-AS provides extended, accurate bass at any volume.

High-Power Transducer and Class-D Amplification

At the heart of the SUB 18-AS is an 18" woofer with a 4.0" voice coil, designed to deliver powerful, low-distortion performance. The precision magnetic circuit maintains consistent flux for balanced output, while the optimized T-pole design reduces modulation for improved clarity. The integrated 2200W Class-D amplifier produces fast transient response and high SPL with minimal heat loss, eliminating the need for a cooling fan. A solid aluminum rear heatsink and advanced safety limiter help preserve signal integrity at all levels.

Bass Motion Control for Extended Low End

RCF's Bass Motion Control (BMC) algorithm replaces traditional high-pass filtering with an advanced excursion-management approach. By mapping the dynamic behavior of the woofer, the system limits only excessive movement, allowing the transducer to reproduce the lowest audible frequencies with extended linearity and improved sound integrity. The result is deeper, more natural bass that doesn't compromise stability or phase response.