At high sound pressure levels, air flow turbulence inside a vented enclosure’s port can create noise that sounds like woofer break up. The patented Slipstream port in Series II enclosures uses a double-flared design to minimize turbulence, and eliminate unwanted vortices.
Most car audio system designs call for 2- or 4-ohm impedance. Series II subwoofers feature an exclusive dual impedance switch that lets you choose either load impedance option. Not available from any other manufacturer, SSI lets you reconfigure your system by simply flipping a switch.