The JBL 2268HPL Differential Drive 18″ speaker is the driver of choice for premium, high quality professional subwoofer systems. Compared with traditional driver designs, JBL’s patented Differential Drive employs a pair of inline voice coils in separate magnetic gaps instead of a single voice coil-gap configuration. Available space is more effectively utilized, and heat is removed from the motor structure more efficiently. Specifically, the voice coils are wound reversely and are immersed in magnetic fields of opposite polarity. This ensures reduced magnetic leakage flux and focuses more magnetic energy in the gaps where it is needed. The 2268HPL is used in JBL’s SRX718, SRX728, and SRX738 speaker systems.