Use HDMI ARC if your TV has it. It is one cable, it lets you control the speakers’ volume with the TV remote, and it carries everything optical can. Optical is the right choice when your TV has no ARC port, or when ARC refuses to behave. For normal TV audio through a pair of stereo speakers, the sound quality is the same on both, so this is a decision about convenience, not fidelity.
What is the difference between HDMI ARC and optical?
Both are ways of sending the sound from your TV to a separate speaker or amplifier. Both are digital, so the signal either arrives intact or it doesn’t. There is no “warmer” cable.
HDMI ARC stands for Audio Return Channel. It runs over an ordinary HDMI cable, in the opposite direction to the picture. Your TV sends its audio back out through one of its HDMI sockets, normally the one labelled “ARC” or “HDMI ARC”, and into your speakers. The same cable can also carry control signals, which is how the TV remote ends up adjusting the speaker volume.
Optical, usually called TOSLINK or “digital optical out”, sends the audio as pulses of light down a thin fibre. The plug is square, with a small dust cover, and it only fits one way round. It carries sound and nothing else: no volume commands, no on/off signals.
Does HDMI ARC sound better than optical?
For stereo speakers, no. Standard ARC and optical can both carry two-channel stereo and compressed surround formats such as Dolby Digital and DTS. Whichever you use, a pair of speakers receives the same stereo signal, converts it to analogue in the same way and plays it back. If anyone tells you one sounds richer than the other for ordinary TV, films and streaming, they are almost certainly hearing a difference in settings or volume, not in the cable.
The difference only appears with high-bandwidth surround formats. Optical does not have the capacity for lossless multichannel audio. Standard ARC is not built for it either. That is the job of eARC, the enhanced version, covered below. If you are listening to a stereo pair, you will never reach the limits of either.
Which is easier to live with day to day?
HDMI ARC, by a clear margin, for one reason: control.
When ARC is working properly, you switch the TV on and the speakers usually wake up. Press volume on the TV remote and the speakers’ volume changes. Switch the TV off and the speakers normally follow. You can leave the speakers’ own remote in a drawer.
Optical cannot do this. It carries sound only, so the TV has no way of telling the speakers to do anything. Many TVs also fix the volume on their optical output, which means the TV remote’s volume buttons change nothing. You will normally be using a second remote for the speakers, or teaching the TV remote to operate them, if your TV supports that.
If you share a living room with other people who just want to watch the television, this is the part that matters most.
When should you choose optical?
Optical earns its place in a few situations:
Your TV has no ARC socket. Some older sets have an optical output but no HDMI ARC. Optical will do the job perfectly well.
ARC is unreliable on your TV. The control side of HDMI can be fussy, particularly with several devices plugged in. If the speakers drop out, switch on late or lose volume control, optical is the stable fallback.
Your ARC socket is already taken or hard to reach. Some TVs have only one ARC port, and it may be used by a games console or a receiver you want to keep.
You prefer a simple signal path. With no control layer there is less to go wrong.
The trade-off is the one above: you lose remote control through the TV, and an optical cable is more fragile than an HDMI cable, so avoid sharp bends and never force the plug.
What about eARC?
eARC is a newer version of ARC with far more bandwidth. It can carry the lossless surround formats that standard ARC and optical cannot, and it also carries a more reliable control link. You will see it printed beside an HDMI socket on recent TVs, usually as “eARC/ARC”.
Do you need it? Only if you have a speaker system that decodes those lossless surround formats and you play content that uses them. For stereo speakers it makes no audible difference. A speaker with a normal HDMI ARC input will still work from an eARC socket, because eARC is backwards compatible with ARC. A standard HDMI cable usually works, though it is worth using a cable sold as High Speed if you want eARC to run reliably.
How do you set up HDMI ARC?
Find the HDMI socket on the TV marked ARC or eARC. It is usually one specific socket among several, not all of them.
Plug an HDMI cable into that socket and into the HDMI ARC input on your speakers.
In the TV’s sound menu, set the audio output to HDMI ARC or “external speakers” rather than “TV speakers”.
Switch on HDMI control in the TV’s settings. It has different names on different TVs, but it is often listed under external devices or HDMI-CEC.
If you get stereo but no surround, or no sound at all, set the TV’s digital audio output format to PCM or “stereo”. Stereo speakers do not need anything else.
Test the volume buttons on the TV remote.
Keep your other devices, such as your games console, streaming stick and set-top box, plugged into the TV’s other HDMI inputs. The TV sends their audio on to the speakers through the ARC connection.
How do you set up optical?
Take the small dust caps off both ends of the optical cable.
Plug one end into the TV’s “digital audio out” or “optical out” socket and the other into the speakers’ optical input. The plug only fits one way.
In the TV’s sound menu, set the audio output to “optical”, “digital out” or “external speakers”.
Set the digital audio format to PCM, or stereo, if you hear nothing or distorted sound.
Turn the TV’s own speakers off if the setting is available, so you don’t hear a second source.
Set the speakers’ volume using their own remote or the controls on the speaker.
Why is there no sound?
Most “no sound” problems are settings, not faults:
The TV is still sending sound to its own speakers. Check the audio output setting.
The wrong input is selected on the speakers. Make sure they are on HDMI ARC or optical to match the cable you used.
The format is set to something the speakers can’t decode. Switch the TV’s digital output to PCM.
The cable is in the wrong HDMI socket. If it is not the ARC one, nothing arrives.
HDMI control is switched off. The speakers may play sound but ignore the remote.
An optical cable is loose or has its dust cap on. Take the caps off and push the plug in until it clicks.
Which uStream speakers use which?
The uStream One, uStream Two and uStream Three each have both HDMI ARC and optical inputs, so you can use whichever your TV supports. The uStream Cube connects to a TV by HDMI ARC. Connect a uStream Cube or uStream One over HDMI ARC and you control them with the same remote you already use for the TV.
If you are still deciding what kind of speakers to put by your TV, our guide to the best kind of speakers for a TV compares the options, and the soundbar vs stereo speakers page explains why a pair beats one long box. You can see which model suits your room in the uStream range.
Frequently asked questions
Can HDMI ARC and optical be used at the same time?
You can connect both cables, but the TV will send audio to only one of them at a time, chosen in its sound settings. There is no benefit to running both. Pick one, and leave the other as a back-up if the first misbehaves.
Is HDMI ARC or optical better for a soundbar or speakers?
For stereo speakers or a soundbar playing normal TV, they sound the same. HDMI ARC is easier to use because the TV remote controls the volume, so use it if your TV has an ARC socket. Use optical if it does not, or if ARC is unreliable.
Do I need a special HDMI cable for ARC?
Normally not. A standard HDMI cable carries ARC. If your TV and speakers support eARC, a cable sold as High Speed is the safer choice, but an expensive cable makes no difference to the sound.
Why does the TV remote not change the volume with optical?
Optical carries sound only, with no control signals, so the TV cannot tell the speakers to change volume. Use the speakers’ own remote, or switch to HDMI ARC if your TV has the socket.
