HDMI ARC and Digital Optical are very different as far as what they can support. Basically here's what each supports! Digital Optical: 2 channels of uncompressed PCM audio or up to 5.1 channels of compressed audio. End of story. This is the max that digital optical is capable of supporting. HDMI ARC: All TVs: 2 channels of uncompressed PCM audio or up to 5.1 channels of compressed audio. TVs made around or after 2018 may support up to 7.1 channels of compressed audio, including height or upward-firing channels. Follow me on Instagram! http://bit.ly/JonahMatthes_IG Most Recommended High-End Soundbars on Amazon: Sonos Arc System (paid link): https://geni.us/YCOhC Samsung HW-Q950T (paid link): https://geni.us/otbvO JBL Bar 9.1 (paid link): https://geni.us/YNFZ Nakamichi Shockwafe Ultra (paid link): https://geni.us/ICkm Most Recommended High-End Soundbars in the United States: Sonos Arc System (paid link): https://shop-links.co/1724442808276614387 Samsung HW-Q950T (paid link): https://shop-links.co/1724442870987287012 JBL Bar 9.1 (paid link): https://shop-links.co/1724442888311453956 Nakamichi Shockwafe Ultra (paid link): https://shop-links.co/1724442957780731452 Purchases made through some store links may provide some compensation to us. SUBSCRIBE to the Channel: https://bit.ly/2UyfDlS My Website: https://thehometheaterdiy.com/