Subwoofer Cable RCA Splitter 1 Female to 2 Male, HOSONGIN RCA Y Adapter Splitter 7445056046061 | eBay
Canare Premium Powered RCA to RCA Subwoofer Cable (1')
Monoprice Onix Series Digital Coaxial Audio/Video RCA Subwoofer CL2 Rated Cable, RG-6/U 75-ohm 6ft - Monoprice.com
Why Subwoofers Should be Connected With an RCA - REL Acoustics
Subwoofer S/PDIF Audio Digital Coaxial RCA Composite Video Cable (30 Feet) - Gold Plated Dual Shielded RCA to RCA Male Connectors - Black - Walmart.com
20FT Subwoofer Cable w/ Y Adaptor | Outdoor Speaker Depot