JBL SRX818S Passive Subwoofer 18” 12-foot envelope followers - these are

envelope followers - these are just a handful of the included modules that can be connected in almost any way imaginable

Efficient forced-air fans prevent excessive thermal buildup

Clock sync with multiple standards

Impedance: 8 ohms

When it comes to recording with microphones

JBL SRX818S Passive Subwoofer 18” 12-foot envelope followers - these are18" Passive Subwoofer System SRX818S is a single 18 subwoofer for concert, touring, or installed use. Featuring a standard M20 pole cup for use with top boxes, indexing feet for stacking in both the standard and cardioid position, and a 136dB max SPL, the SRX818S is an ideal solution for musicians, bands, and DJs, concert use, public speaking, or installations such as performance venues, corporate spaces, educational facilities or houses of worship.