the introduction of HDMI ARC on smart TVs, soundbars, and AV receivers has established HDMI as a comprehensive solution for transmitting and receiving audio data between a host device and AV components. However, this does not imply that optical is outdated: For those with older home theater systems, it might even be the sole connection available.
Nonetheless, digital optical supports a maximum of 5.1 for surround sound processing. Thus, even if you aspire to connect a pre-HDMI ARC era TV with a modern Atmos-enabled soundbar, you’ll encounter a steep limitation quickly.
Optical simply lacks the bandwidth required to transmit object-based audio. If you desire those overhead channels, immersive effects, and the entire Atmos experience, HDMI is the only pathway to achieve that. Additionally, object-based surround formats like Dolby Atmos and DTS:X are not the sole benefits of connecting your sound system through HDMI. HDMI eARC has also played a role in standardizing lip-sync correction and HDMI CEC. This results in a more seamless home theater experience that allows you to use your TV remote to control the volume of your soundbar or speaker system.
In fact, if you intend to set up a fully uncompressed 7.1 audio system or higher — and budget is not a concern — you should ensure that all your home theater equipment is utilizing HDMI eARC. While HDMI ARC can manage stereo and 5.1 surround formats like Dolby Digital and Dolby Atmos, it does so with compression. The only way to experience formats like Dolby Atmos and Dolby TrueHD in their authentic, lossless versions is through HDMI eARC with an Ultra High Speed HDMI cable.
