eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm The LAB 12C, from Eminence, is a 4-ohm take on the original LAB 12 subwoofer. The 12C features the same long-throw construction with a heavy-duty 12-spoke die-cast aluminum frame and Kevlar reinforced paper cone. A lower impedance voice coil is designed to handle 500W RMS, 1,000W program power, and extract even more power from your amplifier, while nickel-plated, spring-loaded speaker terminals offer quick connection. Proudly made in the U.S.A. Eminence"s LAB 12C is designed to perform optimally in a small, sealed 1 cubic foot enclosure, or a 1.25 cubic foot vented enclosure (using a 4" diameter port that is 14.75" long for a 38 Hz tuning frequency) for automotive use. When used in either application, it is recommended to use a steep 35 Hz high-pass filter. For home theater use, Eminence recommends a 4.5 cubic foot ported enclosure using a 4" diameter port that is 14.5" long that tunes the cabinet to 28 Hz and yields an F3 of 29 Hz. When used in this manner, a steep 25 Hz high pass filter is recommended.