The SD-3 series truly is a world-class sound quality woofer with low mounting depth, small box requirements, and a reasonable price. This line features an under-hung motor topology this means that the voice coil is shorter than the top plate so the amount of winding in the gap doesnt change at all over the center portion of stroke in this case featuring a 1 thick top plate and 1/2 long 8-layer copper voice coil. This allows for 0.57 (14.5mm) linear excursion one-way while maintaining an extremely flat BL curve.The large inverted rubber surround & high-stroke spider also allow for a very even compliance curve over the full range allowed by the SD-3 series. To further reduce distortion a large Magnet ID faraday ring has also been included. Sundows borrowed some technology from their large high-excursion woofers and incorporated a hyper-extended pole-piece into the SD-3 line. This helps to prevent voice coil rocking & related damages at high levels of stroke since the SD-3 has such a soft suspension and shallow depth it would be more prone to this without the hyper-extended pole. But, thanks to Sundown's extensive experience in building high-stroke subwoofers they were able to incorporate the ideal solution. Sundown Audio SD-3 8 D4 8 300W RMS Dual 4-Ohm SD Series Subwoofer. Voice Coil Configuration: Dual 4-Ohm. Under-Hung low distortion motor topology. Solid pole piece with chamfered edges. Black Aluminum 2.5 voice coil former for superior heat dissipation. High Temperature 8-Layer copper voice coil wire. Large aluminum faraday ring (Magnet ID).
Optimized for small sealed enclosures 0.25-0.33 cubes sealed. Inverted Rubber Surround to reduce front-mount depth. High strength cast aluminum frames. DC Resistance (Re): 6.1.
Resonance Frequency (Fs): 46.4 Hz. Equivalent Volume (Vas): 5.8 L. Electrical Q Factor (Qes): 0.67.
Mechanical Q Factor (Qms): 3.97. Total Q Factor (Qts): 0.57. Force Factor (BL): 16.4 NA. Air Load (Mms): 100.7 g. Suspension Compliance (Cms): 0.12 mm/N.Sensitivity: 81.2 dB 1w / 1m. Outside Diameter: 8.375 in. Cutout Diameter: 7.375 in. Recommended Port Area: 8 - 12 sq.
In order to maintain an inventory of 100%, Brand New, A-Stock, untouched products, all sales are final. We ask that you please be sure you are ordering the correct product.The item "SUNDOWN AUDIO SD-3 8 D4 CAR 8 300W RMS DUAL 4-OHM SUBWOOFER BASS SPEAKER NEW" is in sale since Tuesday, July 30, 2013. This item is in the category "Consumer Electronics\Vehicle Electronics & GPS\Car Audio\Car Subwoofers". The seller is "woofersetc_outlet" and is located in Los Angeles, California. This item can be shipped worldwide.