RMS 600 watts Dual 2 or 4 ohm voice coils Optimized for small, sealed enclosures Lightweight Neodymium motor Computer-optimized foam “w” surround Two-inch 8-layer copper voice coil Large aluminum Faraday ring for smooth acoustic response Patented high strength cast aluminum frame Low distortion motor construction High-temperature voice coil wire Spring-loaded terminals Stitched-on tinsel lead wires   The SD-4 series truly is a world-class sound quality woofer with low mounting depth, small box requirements, yet extraordinarily high power handling. It's the ideal choice for anyone seeking a high-quality, low-mounting-depth subwoofer that performs hammers in small enclosures. With enhanced mechanical durability and superb sound quality, you get the perfect marriage of form and function. Specifications T/S SPECS SD-4 12″ D2 SD-4 12″ D4 RE (Ohms) 3.93 7.01 FS (Hz) 26.0429 26.7489 VAS (L) 63.5142 64.3194 Qes 0.6187 0.7374 Qms 5.4253 5.5061 Qts 0.5554 0.6503 Le (mH) 6.2790 8.6610 BL (NA) 14.9216 17.9033 Mms (Grams) 214.4713 200.7540 Cms (uM/N) 174.1371 176.3448 Sens (dB @ 1w/1m) 84.33 83.97 Enclosure Specifications Sealed Enclosure 0.8-1.0 cu ft Ported Enclosure Not Recommended Recommended Tuning N/A Recommended Port Area N/A Displacement 0.1 cu ft Depth 4.91″ Outside Diameter 12.51" Cut-Out 10.94" Physical Dimensions Download