Amazon.com: Devinal RCA Y Cable, RCA/Phono Y Splitter, RCA 1 Male to 2 Male Y Adapter, Male/Male Subwoofer Cable Gold Plated for subs/amps/Hi-Fis/Home Theater/receivers 6.5Feet/2M : Electronics
Subwoofer split cable (Y-split) | AV-Connection
How To Solder an Audio Cable DIY RCA Y Adapter for Subwoofer - YouTube
RCA Y Adapter Subwoofer Y Cable 1X RCA to 2X RAC Audio Cable,3 Meter - Walmart.com