Turn a television around, and you will find a cluster of ports with abbreviated labels that are rarely explained in the manual and seldom explained in the store. Getting this right matters more than most people realise, because plugging a device into the wrong port genuinely limits what it can do.
HDMI — The Baseline
Standard HDMI ports are labelled HDMI 1, HDMI 2, HDMI 3, or similar. Any HDMI cable carrying video and audio signals works in any of these. The version of HDMI the port supports (1.4, 2.0, 2.1) determines the maximum resolution and refresh rate it can carry.
HDMI 1.4 supports 1080p at 60Hz. HDMI 2.0 handles 4K at 60Hz. HDMI 2.1 handles 4K at 120Hz and 8K. If you have a gaming console from the current generation and you want 4K at 120fps, you need to plug it into an HDMI 2.1 port. Not all ports on a TV are the same version — typically, only one or two ports on a modern TV support HDMI 2.1. Plugging your console into the wrong one caps your frame rate at 60fps regardless of your TV or console settings.
ARC — Audio Return Channel
ARC is the port to use for your soundbar or AV receiver. Without ARC, you need a separate audio cable to send TV sound to your external speakers. With ARC, the HDMI cable you already have between the TV and the soundbar carries audio in both directions — video into the TV from the soundbar’s HDMI input, and audio out to the soundbar from the TV. One cable handles everything.
The limitation: ARC supports compressed audio formats (Dolby Digital, DTS) but not the uncompressed or object-based formats (Dolby TrueHD, DTS:X, Dolby Atmos in its full form). If your soundbar supports Atmos and you want the full quality, you need eARC.
eARC — Enhanced Audio Return Channel
eARC is ARC with significantly more bandwidth. It supports lossless audio passthrough, meaning Dolby TrueHD and full Atmos tracks from streaming services and 4K Blu-ray players come through at their full quality rather than a compressed version.
To use eARC, both your TV and your soundbar or receiver need an eARC-compatible port, and they need to be connected with a High Speed HDMI cable (not the older Standard Speed cables that might be in a drawer somewhere). The ports are labelled — the TV’s eARC port is almost always HDMI 1 or a dedicated port with an ‘eARC’ label beside the port number.
HDMI 2.1 and eARC Together
On many modern televisions, the HDMI 2.1 port and the eARC port are the same physical port. This creates a real-world conflict: if you have a current-generation gaming console and a soundbar, they both want that port. The workaround is an AV receiver that has HDMI 2.1 passthrough — your console connects to the receiver, the receiver connects to the TV via eARC, and everything routes through correctly. It is a slightly more expensive setup, but it eliminates the port conflict entirely.
Why Getting This Wrong Is Common
TV manufacturers’ manuals list these specifications but do not clearly explain their practical implications. Retailers sell the hardware without walking through the connection requirements. The result is that many people with high-quality TVs and soundbars are running connections that actively limit the performance of both devices.
If you are having a TV installed professionally, specifying your soundbar and any gaming consoles or streaming devices in advance allows the installer to plan the cable routing and connections correctly from the start — rather than discovering on the wall that the only accessible port is the wrong one.