6" Car Audio Speaker Subwoofer - 300 Watt High Power Bass Surround Sound Stereo Subwoofer Speaker System w/ Molded P.P. Cone, 86 dB, 4Ohm, 40 oz Magnet,1 inch KAPTON Voice Coil - Pyramid PW677X : Electronics - Amazon.com
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Loudspeaker Impedance 4-Ohm vs 8-Ohm: Which is Better? - YouTube
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