SRX918S Subwoofer + ACK1 Caster Kit

The SRX918S and ACK1 bundle gives rental companies, touring bands, and installers an 18-inch powered subwoofer that shows up ready to roll. The SRX918S houses a JBL 2279G-1 18-inch woofer with a dual 3-inch voice coil, dual gap design that sheds heat better and holds up through long, loud sets with less power compression than single-coil woofers. A built-in, passively cooled 1,100W Class D amplifier with a universal power supply reaches 134 dB max SPL and digs down to 35 Hz, so kick drums and synth bass hit hard in clubs, ballrooms, and on outdoor stages.

Onboard DSP, LevelMax limiting, and a rear-panel LCD put every setting within reach, and dual etherCON ports with HARMAN HControl support let you network the system and adjust it from Windows, macOS, or iPad OS software. Switch to cardioid coverage to keep low end off the stage, where it muddies monitor mixes, and the large low frequency port moves air without audible chuffing at high output.

At 98 lb, an 18-inch sub is a two-person lift, which is where the ACK1 earns its spot. The kit adds four tour grade 3-inch casters rated for 220 lb each, with black polyurethane wheels and black housings that stay discreet in cardioid stacks where the rear of the cabinet faces the crowd. Anti-rattle hardware keeps the casters quiet while the sub plays, and the reinforced 18mm plywood cabinet with two recessed handles stands up to load-in after load-in.