Stereo to Mono Audio Converter - Vanco International
RCA Stereo to Mono converter where to buy ? | Audio Science Review (ASR) Forum
Amazon.com: RCA Male to 3.5mm Female Adapter, 2 Pack RCA Plug to 1/8" Female Mono Jack Audio Connector Converter, Gold Plated UIInosoo for Receiver, Subwoofer, Speaker, Audio Equipment : Electronics
Amazon.com: SPRODIO Single Stereo to Mono Converter, RCA L/R Audio Adapter Stereo to Mono summing Cable Adapter SC21 : Musical Instruments
Amazon.com: C2G Legrand RCA Male to RCA Female Signal Splitter Cable, Black RCA to RCA Splitter, 6 Inch Audio Stereo Y-Cable, 26 AWG Audio Signal Converter Cable, 1 Count, C2G 03177 : Electronics
Rolls DB226 Stereo Line to Balanced Mono Converter DB226 B&H
RCA / Cinch Y-adapter (stereo to mono downmix for subwoofer) by jk_printer | Download free STL model | Printables.com
Earphone Audio Jack 3.5mm Connector Stereo Adapter Male Female RCA Audio Mono Channel Plug to Screw Terminal Mono Channel Plug - AliExpress