An optical cable, also called Toslink, sends digital audio from a TV to a soundbar through a thin fiber-optic connection. It is a dependable option when HDMI ARC is unavailable or unreliable.
Optical setup is simple, but both devices must be set correctly. The TV needs to send audio through Optical or External Speaker, and the soundbar must be on its Optical input.
Does this affect you?
Use this if your TV and soundbar both have ports labeled Optical, Toslink, Digital Audio Out, or Optical In, or if an already-connected optical cable produces no sound.
Connect the optical cable
- Find the TV port labeled Optical, Optical Out, Toslink, or Digital Audio Out (Optical).
- Find the soundbar port labeled Optical In or Digital Audio In.
- Remove the small plastic caps from both ends of the optical cable.
- Insert one end into the TV and the other into the soundbar. The plug fits only one way, so do not force it.
- Turn on the soundbar and choose Optical or OPT as the input.
Optical cable ends are small and squared off. If the connector will not seat, rotate it rather than pushing harder.
Set the TV audio output
Open the TV sound menu and select Optical, External Speaker, Digital Audio Out, or a similar output. Samsung, LG, Sony, and other brands use slightly different names, but the setting is normally under Sound, Sound Output, Sound Out, or Speakers.
If the TV is still set to TV Speaker, the soundbar can be connected perfectly and still stay silent.
Fix no sound or distorted sound
- Confirm the soundbar is on Optical input, not Bluetooth, HDMI, or Aux.
- Re-check the TV sound output and make sure it is not set to internal speakers.
- If sound crackles, cuts out, or is distorted, set the TV’s digital audio format to PCM or Dolby Digital.
- Turn off advanced passthrough formats such as Dolby Digital Plus or Dolby Atmos passthrough when using optical.
- Inspect the cable ends and try another optical cable if the fiber appears bent, cracked, or damaged.
Optical has less bandwidth than HDMI eARC. It can carry stereo and standard 5.1 surround, but not modern object-based formats such as Dolby Atmos or DTS:X.
Know the optical limitations
Unlike HDMI ARC/eARC, optical usually does not let the TV remote control soundbar volume automatically. You may need the soundbar remote unless your TV offers universal remote setup.
If your soundbar has only red/white RCA or a 3.5mm AUX input, that is analog audio, not optical digital audio. It can still work, but it will not carry digital surround formats.
Sources
- Samsung Support – Connecting a soundbar using an optical cable (2025)
- LG Support – Digital audio output settings for external sound systems (2025)
- Sonos Support – Connect Sonos to your TV using an optical cable (2025)