The JBL LSR310S is a powered 10-inch studio subwoofer with a 200 W Class-D amplifier, optimised to extend the low end of JBL's 3-Series monitors for music recording, mixing and 5.1 post-production. Its 10-inch driver and JBL's Slip Stream port deliver a peak output of 113 dB. A selectable Extended Low Frequency (XLF) mode lifts the sub-bass in the way many dance clubs do, so you can hear how a track will translate on a club system. Setup is flexible: selectable input sensitivity, two balanced XLR inputs, two balanced quarter-inch TRS inputs and two XLR outputs, and three crossover settings — 80 Hz, XLF (120 Hz) and external for use with an outboard crossover. It gives a 3-Series rig the low-frequency weight needed for full-range monitoring and low-frequency effects.