In this guide
HDMI ARC carries bidirectional audio and video over one cable and supports up to Dolby Atmos via eARC. Optical audio is audio-only, limited to compressed 5.1 surround sound, and works well with older devices.
- Both devices have matching ARC or eARC ports (HDMI ARC)
- CEC is enabled on TV and soundbar for volume sync
- Optical used for stereo or basic 5.1 with older gear
- Cable is undamaged and connectors click firmly into place
- One device lacks an ARC/eARC port
- CEC is disabled, breaking sync between devices
- You need lossless 7.1 or Dolby Atmos over optical
- Optical cable is bent sharply or the end is cracked
How Each Connection Works
HDMI ARC (Audio Return Channel) was introduced in HDMI 1.4. It lets a TV send audio back down the same HDMI cable connected to a soundbar or AV receiver, eliminating a separate audio cable. The upgraded eARC standard (HDMI 2.1) adds enough bandwidth for lossless Dolby TrueHD and Dolby Atmos.
Optical audio, also called Toslink, uses a fiber optic cable that transmits light pulses. It carries audio only, has no video capability, and tops out at compressed Dolby Digital or DTS 5.1. It cannot handle the higher bitrates required for lossless surround formats.
Format Support Comparison
| Setup | Works? | Need | Note |
|---|---|---|---|
| Dolby Atmos via HDMI eARC | Yes | eARC TV + soundbar, HDMI 2.0+ cable | Best quality option |
| 5.1 surround via HDMI ARC | Yes | ARC ports on both devices, CEC on | Compressed formats only on ARC |
| Stereo via Optical | Yes | Toslink cable, matching ports | Reliable for simple setups |
| Dolby Atmos via Optical | No | — | Optical bandwidth too low |
| 7.1 lossless via Optical | No | — | Not supported over Toslink |
When to Choose HDMI ARC
Choose HDMI ARC if your TV and soundbar both have ARC or eARC ports and you want the cleanest setup. One cable handles everything, and CEC lets the TV remote control your soundbar volume. If you want Dolby Atmos or TrueHD, eARC is the only consumer cable option that delivers it. See the full HDMI ARC vs optical breakdown at Cable Matters for more technical detail.
If your TV has a USB-C port instead of HDMI, check whether USB-C can connect to HDMI before buying a soundbar with only HDMI ARC input.
When to Choose Optical
Optical is the right pick when one of your devices is older and lacks HDMI ARC, or when you are connecting a game console or Blu-ray player directly to a receiver without a TV in the chain. It is immune to electrical interference and simple to configure — no CEC settings to troubleshoot.
Optical is also a reliable fallback if you run into adapter or HDMI handshake problems with a newer display. Just keep the cable straight — Toslink fiber cracks under sharp bends and the connection fails silently.
Quick Checklist Before You Connect
- Confirm both devices show ARC or eARC labels on the port
- Enable HDMI-CEC in TV settings (may be called Anynet+, Bravia Sync, or Simplink)
- Use a quality HDMI 2.0 or higher cable for eARC bandwidth
- For optical, inspect both ends for cracks and seat them until they click
Bottom line: HDMI ARC is the better choice for modern home theater setups — it supports higher audio formats, reduces cable clutter, and enables device sync. Optical remains a dependable fallback for older equipment or basic stereo and 5.1 needs where simplicity matters more than format support.