HDMI eARC vs ARC vs Optical vs USB Audio: Which Connection Should You Use?

Audio connection guide

HDMI eARC vs ARC vs optical vs USB audio

Shortlist at a glance

These products illustrate three different jobs. Buy only the route your source and audio device both support.

HDMI eARC vs ARC vs optical vs USB

How we chose these examples

We compared the connection requirements in official HDMI and device guidance with exact Australian retail listings checked on 28 September 2026. This is research-led guidance, not hands-on testing. The connection type is the main decision; cable branding does not confer unsupported features.

Three connection examples

HDMI eARC / ARC

Gtek Gaming Ultra Certified V2.1B HDMI Cable, 2 metres

An exact Australian retail example when you actually need a new HDMI cable.

TV-to-soundbar routeResearch-led example

Why choose it

• Certified Ultra High Speed option for a demanding video setup
• One HDMI connection can carry TV audio and control when the ports support ARC/eARC

Check first

• No benefit from replacing a working compliant cable solely for stereo sound
• eARC requires support in the TV and sound system

Best for: Modern TVs and soundbars with matching ARC or eARC ports.

Gtek HDMI 2 mJB Hi-Fi

Optical audio

ALOGIC TL-AD-02 Premium 2m Fibre Toslink Cable

A straightforward optical connection when both devices have TOSLINK sockets.

Legacy TV audioResearch-led example

Why choose it

• Good for stereo PCM and compatible compressed surround
• Avoids HDMI CEC control and electrical ground-loop paths

Check first

• No high-bandwidth lossless surround
• TV remote volume control generally needs another method

Best for: Older soundbars, DACs and amplifiers with optical input.

ALOGIC TL-AD-02Scorptec

Computer / phone

FiiO KA11 Type-C DAC and Headphone Amplifier, Silver

An exact-model USB audio example for personal listening from a compatible host.

USB DAC exampleResearch-led example

Why choose it

• Small USB-C path from a compatible phone or computer to wired headphones
• Useful where the host supports external USB audio

Check first

• Does not make an ordinary TV USB port a live audio output
• Check device, connector and headphone compatibility

Best for: Compatible USB-C phones, tablets or laptops and wired headphones.

FiiO KA11 USB-CJB Hi-Fi

What is HDMI ARC?

ARC stands for Audio Return Channel. It allows a television to send audio back through a compatible HDMI connection to a soundbar or AV receiver.

Without ARC, an HDMI cable may carry video and sound from a source into the television, but a separate audio cable may be needed to return sound from the TV’s apps or tuner to the audio system.

For ARC to work:

• the television must have an HDMI port marked ARC or eARC;
• the soundbar or receiver must have a compatible HDMI output marked ARC or eARC;
• the HDMI cable must be connected to those specific ports;
• ARC must be enabled in the device settings; and
• HDMI control or CEC may also need to be enabled.

HDMI CEC is the control system that allows connected devices to communicate. Manufacturers use different names for it, including Bravia Sync, Anynet+, Simplink and Viera Link.

What is HDMI eARC?

eARC stands for Enhanced Audio Return Channel. It improves on ARC by providing much greater audio bandwidth and more robust handling of modern audio formats.

HDMI Licensing Administrator states that eARC can support high-bitrate formats, including uncompressed multichannel audio, Dolby TrueHD, Dolby Atmos, DTS-HD Master Audio and DTS:X when the complete equipment chain supports them.

That makes eARC the preferred connection for:

• higher-end soundbars;
• AV receivers;
• multichannel home-theatre systems;
• lossless audio from Blu-ray or compatible media sources;
• modern game consoles; and
• televisions used as the central connection point for several devices.

Is eARC noticeably better than ARC?

It depends on the content and equipment.

For ordinary stereo television, news, free-to-air broadcasts and many streaming services, ARC may sound identical to eARC. The difference becomes important when passing high-bandwidth or lossless multichannel sound.

ARC can carry common formats such as stereo PCM and compressed surround audio under compatible conditions. Some equipment can also carry Dolby Atmos when it is packaged within a compressed Dolby Digital Plus stream.

eARC is required when you want to pass formats such as lossless Dolby TrueHD with Atmos or other high-bandwidth multichannel audio through the television.

What is optical audio?

Optical digital audio—also called TOSLINK or optical S/PDIF—uses light to send a digital audio signal through a fibre-optic cable.

It is widely found on televisions, older soundbars, stereo amplifiers, DACs and home-theatre equipment.

Optical can commonly carry:

• two-channel PCM stereo;
• compressed Dolby Digital surround sound; and
• compressed DTS on compatible devices.

It generally cannot carry the high-bandwidth lossless formats supported by eARC, such as Dolby TrueHD or DTS-HD Master Audio. Format support also depends on the source and receiving device.

When optical is the better choice

HDMI eARC is more capable, but optical can still be the smarter practical option when:

• the soundbar or amplifier has no HDMI ARC connection;
• HDMI control repeatedly turns devices on or off unexpectedly;
• ARC suffers from dropouts or unreliable handshaking;
• you need only stereo sound;
• the audio system supports the required compressed format over optical; or
• you want a simple connection without HDMI device control.

Optical also creates electrical isolation between devices because the signal travels as light. This can help avoid some electrical ground-loop noise, although it does not solve every type of hum or interference.

What is USB audio?

USB audio allows a computer, phone, tablet or another compatible host device to send digital audio directly to a USB DAC, amplifier, powered speaker or headphone system.

Unlike optical, USB can support two-way communication. The source and audio device may exchange information about available formats, sample rates, volume and device status.

USB audio is particularly useful for:

• desktop computers connected to a DAC;
• laptops connected to powered speakers;
• compatible phones or tablets connected to a portable DAC;
• headphone listening; and
• high-resolution stereo music playback.

The achievable format and resolution depend on the source, operating system, application, DAC, driver requirements and USB connection.

Why a TV’s USB port usually is not an audio output

Television USB sockets are commonly provided for:

• powering small accessories;
• playing media from storage devices;
• recording broadcasts on supported models;
• firmware updates; or
• service functions.

A USB socket does not automatically mean the television can transmit live sound to a USB DAC, soundbar or headphones.

Some televisions support selected USB audio devices, but this must be confirmed in the model’s manual or official specifications. Do not buy a USB DAC for a TV until compatibility is verified.

Which connection supports Dolby Atmos?

A Dolby Atmos logo on one device does not guarantee that the whole system will play Atmos. The content, app, source device, television, selected output mode, connection and sound system must all support a compatible format.

Which connection supports lossless audio?

HDMI eARC is the appropriate TV audio connection for high-bandwidth lossless multichannel formats. It can support Dolby TrueHD, DTS-HD Master Audio and uncompressed multichannel PCM when the devices support them.

Optical is normally limited to stereo PCM or compressed multichannel formats. It is not designed for modern lossless multichannel soundtracks.

USB audio can support lossless and high-resolution audio in a compatible computer or mobile audio system, but it is not usually the correct connection for sending television sound to a soundbar.

Will HDMI improve ordinary stereo sound?

Not necessarily. If both connections deliver the same stereo PCM data correctly, HDMI and optical may produce no meaningful audible difference.

The benefit of HDMI is more often:

• support for additional formats;
• greater bandwidth through eARC;
• volume control from the TV remote;
• automatic power control;
• lip-sync communication; and
• simpler switching between TV sources.

Do not replace a reliable optical connection purely because HDMI is newer if you use only stereo and need none of those additional features.

What cable do you need for ARC or eARC?

ARC does not usually require an expensive cable. A sound, compliant HDMI cable suitable for the equipment and cable length should work.

For eARC and modern high-bandwidth video equipment, use a properly certified cable recommended for the required features. An Ultra High Speed HDMI cable is a sensible choice when the same cable may also need to support demanding video modes.

Avoid paying extra for vague claims such as “audiophile HDMI” or promises that a very expensive digital cable will create richer bass or more detail.

How to connect HDMI eARC or ARC

1. Find the correct TV socket. Use the HDMI port specifically marked eARC or ARC.
2. Find the correct sound-system socket. On a soundbar, it is commonly labelled HDMI OUT, TV eARC or TV ARC.
3. Connect the HDMI cable. Push both ends in firmly.
4. Turn on HDMI control. Enable CEC on the television and audio system if required.
5. Enable eARC or ARC. Set it to Auto or On in the relevant menus.
6. Select the external audio system. Change the TV’s speaker output from internal speakers to audio system or receiver.
7. Choose the digital audio format. Start with Auto or Pass-through if every device supports the source format.
8. Test volume and power control. Confirm that the TV remote operates the sound system correctly.

How to connect optical audio

1. Remove the protective caps. New optical cables may have small clear caps on the ends.
2. Check the socket orientation. The plug fits in one direction and should not be forced.
3. Connect TV Optical Out to the audio system’s Optical In.
4. Select optical input on the soundbar, DAC or amplifier.
5. Change the TV speaker setting. Select optical or external audio output.
6. Start with PCM if there is no sound. Then test other formats only if the receiving device supports them.
7. Set the volume correctly. Optical output may be fixed, requiring the sound system’s remote for volume control.

Why is there no sound over HDMI ARC?

Work through these checks in order:

1. Confirm both ends are connected to ports marked ARC or eARC.
2. Set the soundbar or receiver to its TV audio input.
3. Enable HDMI CEC on both devices.
4. Enable ARC or eARC in both devices.
5. Select Audio System or Receiver in the TV’s speaker menu.
6. Change digital audio output temporarily to PCM.
7. Restart both devices by disconnecting power briefly.
8. Test another known-good HDMI cable.
9. Install current firmware updates.
10. Disconnect other HDMI devices temporarily to identify a CEC conflict.

Manufacturers use different menu names, so consult the manuals for the exact television and audio model.

Why does HDMI sound keep dropping out?

Intermittent sound can be caused by:

• a damaged or marginal HDMI cable;
• loose connections;
• firmware problems;
• HDMI CEC conflicts;
• unsupported audio formats;
• eARC settings that do not match;
• a source changing formats between programs; or
• an unreliable HDMI switch or adaptor.

Test a direct connection with a short known-good cable. Temporarily select PCM stereo. If the problem disappears, reintroduce the preferred settings and connected devices one at a time.

Why is optical connected but silent?

Check that:

• the cable is connected to Optical Out on the TV and Optical In on the audio device;
• the audio system is set to its optical input;
• the TV is set to external speakers or optical output;
• the digital audio format is set to PCM for initial testing;
• the cable is not sharply bent or damaged; and
• the connectors are fully inserted.

If you disconnect the cable from the receiving device while the TV is producing sound, red light is often visible at the end. Avoid staring directly into it. Light confirms a signal source is active but does not prove that the audio format is compatible.

What causes lip-sync problems?

Video processing and audio decoding take time. If the TV delays the picture differently from the sound system, voices may not match lip movement.

Try:

• enabling the television’s automatic lip-sync option;
• adjusting audio delay on the TV, soundbar or receiver;
• using eARC where supported;
• connecting the source directly to the sound system;
• disabling unnecessary video processing for testing; and
• changing the audio format to determine whether decoding adds delay.

Be careful with delay controls: many can delay audio further but cannot make already-late audio arrive earlier.

Should devices connect to the TV or the soundbar?

Connecting devices to the television is usually simplest. The TV handles video switching and sends audio to the soundbar through eARC or ARC.

Connecting a source directly to the soundbar or receiver may be better when:

• the TV cannot pass the source’s preferred audio format;
• ARC bandwidth is inadequate;
• the source requires lossless multichannel audio;
• the sound system provides sufficient HDMI inputs; or
• a pass-through problem has been identified.

However, the soundbar or receiver must also pass the required video resolution, refresh rate, HDR format and gaming features to the television.

Which connection should you use?

Common buying mistakes

• Connecting HDMI to a port that is not marked ARC or eARC
• Assuming every device with HDMI supports ARC
• Expecting optical to carry lossless Dolby TrueHD Atmos
• Assuming a TV’s USB port outputs live audio
• Buying an expensive HDMI cable without checking certification
• Using Auto or Pass-through with a soundbar that cannot decode the format
• Forgetting to enable HDMI CEC
• Blaming the cable before checking the TV’s audio-output setting
• Expecting the TV remote to control volume over every optical connection
• Assuming an Atmos logo means every source and connection will deliver Atmos