Amazon.com: ROOFULL 4Kx2K HDMI to HDMI and Audio (3.5mm Stereo or SPDIF Optical) Extractor Splitter Converter Support Apple TV, Fire TV, Blu-ray Players : Electronics
Amazon.com: HDMI Audio Extractor, HDMI to HDMI + Optical Toslink SPDIF + Analog RCA L/R Stereo Audio Out Support 3D 4K@30Hz : Electronics
Optical vs HDMI: Which Is Better? - RTINGS.com
Product - avedio links
HDMI Audio Extractor 4K, Hdiwousp HDMI to HDMI Audio Optical Stereo 3.5mm Jack, HDMI Audio Converter with HDMI Cable to Toslink SPDIF AUX Output Support HDCP1.4 3D for PS4/Roku/Bul-Ray Set-Top Boxes -
Amazon.com: Tensun 4K HDMI to HDMI Optical SPDIF TOSLINK Converter Adapter with 3.5mm RCA R/L Stereo HDMI Audio Extractor Splitter for Blue-ray PC Laptop Xbox One HDTV : Electronics
HDMI vs. Optical: Which Digital Audio Connection to Use? - CNET
Amazon.com: HDMI Audio Extractor 4K, Hdiwousp HDMI to HDMI Audio Optical Stereo 3.5mm Jack, HDMI Audio Converter with HDMI Cable to Toslink SPDIF AUX Output Support HDCP1.4 3D for PS4/Roku/Bul-Ray : Electronics
Sonos Optical Audio Adapter for Sonos Beam and Arc OPADPWW1BLK