Optical vs Aux for Soundbars: Which Input Wins?

Digital vs analog: what changes

Optical and aux are two ways to carry sound from a TV or music player to a soundbar, and the main difference is the signal type. Optical sends a digital stream as light through a cable. Aux sends an analog electrical signal through a mini-jack or RCA-style cable. The soundbar converts either one into sound, but the signal type affects which devices you can connect and which formats the bar can receive.

Most soundbars include optical and aux inputs. The right choice starts with the output on your source device. If the source has an optical output and the soundbar has an optical input, that is the path to use for TV audio. Aux is the fallback for devices that only provide an analog line-level output. For a full tour of what a soundbar accepts, see inputs and outputs.

Why optical is usually the right choice for TV

For an older TV with an optical output, optical is the strongest wired connection short of HDMI ARC. It keeps the audio digital from the TV to the soundbar, which avoids an extra analog conversion inside the TV. That matters most when the TV is passing compressed surround audio to the bar.

Optical also uses a single cable that is easy to run from a TV to a soundbar. Set the TV audio output to the format your soundbar supports; many TVs label this as PCM or bitstream. If you see a Dolby Digital option and your soundbar can decode it, use it. The PCM vs bitstream choice explains the difference.

One limitation is that optical does not carry the newest object-based audio formats that demand the most bandwidth. For a modern TV, HDMI ARC or eARC is the upgrade path.

When aux still makes sense

Aux is not a defect; it is simply the analog option. It makes sense for source devices that only output analog line-level audio, such as a portable music player, laptop headphone jack, cassette deck, or older CD player. If one of those is your main source, connect it to the aux input on a soundbar and you get a straightforward stereo signal.

Turntables need a little extra care. Most turntables require a phono preamp before a line-level aux input. If the turntable has a built-in phono stage, aux can work; if not, add a phono preamp first. Remember that aux is normally a stereo connection and does not replace a multichannel optical or HDMI hookup for surround TV audio. For advice on music-focused bars, see soundbars for music.

What about HDMI and Bluetooth?

On a newer TV, HDMI ARC is usually better than both optical and aux. HDMI is a digital interface managed by the HDMI Forum and HDMI LA, and the specification continues to add bandwidth for audio and video. ARC uses the same cable for audio return from the TV and can carry more formats than optical. See HDMI connections for the details.

Bluetooth is a separate path for music and casual listening. Bluetooth Classic is the radio used mainly for wireless audio streaming by speakers, headphones, and in-car systems, according to the Bluetooth SIG. It is useful when you want to play music from a phone without docking it, but it is not a substitute for a wired TV connection. If you rely on Bluetooth, check the Bluetooth versions on your soundbar.

Connection standards also matter beyond a single product. The Consumer Technology Association helps set standards for audio and video equipment, which is one reason input labels like optical, aux, and HDMI remain consistent across brands.

How to choose the input on an older TV

Check the back of your TV. If it has an optical output, use optical before aux. If it has an HDMI ARC port, use ARC before optical. If the TV only has a headphone jack or RCA analog outputs, aux is your wired option, and it is still a reliable way to get stereo sound into a bar.

Match the TV audio format to the soundbar. A stereo soundbar or stereo bar with a subwoofer works with stereo PCM. For a multichannel soundbar, choose the bitstream Dolby Digital output on the TV if it is available. The same guidance applies to any bar with surround support.

After you connect the cable, select the matching input on the soundbar. Some bars label it Optical or Aux; others use Input 1, Input 2, or similar names. Use the soundbar remote or app to switch.

Keep volume sensible on any input

Whichever input you choose, the soundbar is capable of reproducing loud sound. Long or repeated exposure to sounds at or above 85 dBA can cause hearing loss, according to the National Institute on Deafness and Other Communication Disorders. If you find yourself turning the volume up to hear dialogue, work on the source level or the soundbar dialogue settings instead.

See maximum output levels and dialogue enhancement for more guidance.

What to pick for your use

Questions

Which is better for a soundbar, optical or aux?

For TV audio, optical is better if your TV has an optical output, because it carries digital audio and can support compressed surround formats. Aux is the better choice for analog-only music players and line-level sources.

Does optical sound better than aux?

It can sound cleaner when the source is digital, because the TV sends a digital stream instead of converting it to analog first. With well-made source devices and a good soundbar, the practical difference is usually small for stereo music.

Can aux carry surround sound?

No. Aux is normally a stereo analog connection. Optical can carry multichannel compressed audio from a TV, while HDMI ARC or eARC can handle more demanding formats.

Why is there no sound from the optical input?

Check the TV audio output setting and choose PCM or a bitstream format the soundbar can decode. Make sure the soundbar is set to the optical input. See no sound troubleshooting.

Can I use both optical and aux at once?

Most soundbars play the input you select at any given time, but you can connect both and switch between them. That setup lets you keep the TV on optical and a music player on aux.