Does this solution work? two AUX speakers do stereo sound - Home Theater Equipment - Linus Tech Tips
1.5m 3.5mm Stereo Female To 2x Male AUX Mono Jack Plug Cable-Audio Splitter Lead: Amazon.co.uk: Electronics & Photo
Saramonic SR-AX100 Passive 2-Channel Audio Mixer Adapter for DSLR Cameras | Camera Centre UK
Audio Adapter 3.5mm Stereo Jack M to 2 Mono Jacks 3.5mm 15cm H - Cablematic
3.5mm Stereo Jack Socket to Twin 6.35mm Mono Jack Plugs Adapter Cable
3.5mm Stereo to 2x Mono Audio Splitter Adaptor | PC Audio Splitter – DJ Supplies Sound and Lighting Ltd
1/4" Jack Headphone Splitter, Mono, by Gear4music at Gear4music
Vanco International | 1/4" Stereo Plug to 2-3.5 mm Mono Plugs "Y" Adapter
Stereo to Mono Splitter Cable for use with ML10X – ThorpyFX Ltd
1/4" Dual Mono Female to 1/4" 6.35mm Mono Male Plug Audio Y Splitter Adapter 636391130677 | eBay
microphone - Combine two mono mics into one stereo signal, such that each mic gets its own channel (left and right) - Sound Design Stack Exchange
terminology - What type of adapter combines 2 mono 3.5mm jacks into 1 stereo 3.5mm jack with each mono track on a different band? - Sound Design Stack Exchange
Hosa Stereo Breakout 3.5 Mm Trs to Dual 3.5 Mm Tsf : Amazon.co.uk: Electronics & Photo
Procab CLA721/1.5 1x stereo jack - 2x mono jack adapter cabl | Bax Music
MainCore 1m long 3.5mm Stereo Jack to Twin 2 x 3.5mm Mono 2 pin 1/8 Jacks OFC Audio Outputs Cable Cord Lead (Available in 0.5m, 1m, 2m, 3m) (1m): Amazon.co.uk: Electronics &
3.5mm Stereo Plug to 2 x Mono Sockets, 15cm - micbooster.com