HDMI ARC vs Optical Audio: Which Connection Is Better for TV Sound?

HDMI ARC and optical can both carry television audio to a soundbar, amplifier, receiver, or streamer. The decisive difference is not automatically sound quality. It is whether the connection also needs to handle remote control, power coordination, input switching, lip-sync information, and modern surround formats.

What HDMI ARC actually does

ARC means Audio Return Channel. A compatible HDMI port can return audio from the TV to an external audio device over the same cable used for video in the opposite direction. HDMI-CEC may add television-remote volume control, power coordination, and automatic input switching.

ARC must be enabled on both products, and the correct HDMI sockets must be used. A port labelled only HDMI is not necessarily the ARC port. Brand-specific CEC names can also make setup confusing.

What optical does

Optical TOSLINK carries S/PDIF audio as light. It is simple, widely supported, and electrically isolated. It normally carries stereo PCM and may carry compressed multichannel formats when both products support the same format. It does not normally transmit volume commands or power control.

ARC, eARC, and format support

Standard ARC has less bandwidth than eARC. eARC was designed for higher-bandwidth formats and improved device communication. The useful format is still limited by the TV, source app, TV audio settings, cable, and receiving device. A product saying “HDMI ARC” does not imply eARC, Dolby Atmos, lossless multichannel, or every codec.

For a two-channel music system, stereo PCM is often the correct setting. Some streamers and stereo amplifiers accept Dolby Digital 5.1 through HDMI ARC and downmix it, while others require PCM. Check the manual rather than assuming.

Remote control and everyday use

ARC is usually more convenient because the TV remote can control the connected audio system through CEC. Optical volume control depends on the television or receiver design and may require a second remote. CEC is useful but not perfectly standardized: mixed-brand systems can experience delayed switching, unexpected power behaviour, or lost handshakes.

Lip-sync and reliability

HDMI includes mechanisms intended to coordinate audio and video timing, but apps and devices can still introduce delay. Optical is independent of the HDMI chain and may be more predictable in a simple stereo setup, but lip-sync adjustment may need to be set manually in the TV or audio device.

When optical is the better choice

• You need electrical isolation to eliminate hum.
• The audio device has no ARC input.
• You want a simple stereo PCM link without CEC behaviour.
• An HDMI handshake problem is causing intermittent audio.

When HDMI ARC is the better choice

• You want one remote for TV power and volume.
• You want automatic switching when the television turns on.
• Your system needs formats or control features beyond optical.
• The receiving device is designed around TV integration and subwoofer management.

Setup checklist

1. Use the television port labelled ARC or eARC.
2. Enable CEC and ARC/eARC on both devices.
3. Start with stereo PCM if a two-channel device produces silence.
4. Confirm whether the receiver accepts Dolby Digital, not only whether the TV can output it.
5. Disable TV speakers if the television does not switch automatically.
6. Test lip-sync using spoken dialogue.

Bottom line

Choose HDMI ARC for integrated TV control and broader format capability. Choose optical for isolation, simplicity, or compatibility with older stereo equipment. For two-channel listening, a stable optical PCM connection can be entirely appropriate; ARC is mainly the more complete control system.

Editorial classification: connection and system-design guide. Verify current format support in the manuals for both products.