You own a 4K Ultra HD TV, QLED TV or OLED TV and want to play the sound on your AV reciever or on your sound bar. How do you recieve the sound from the TV on the home theater system? Which connection should you choose to achieve the best results? What are the differences between a Toslink optical connection, an HDMI ARC connection and an HDMI eARC connection?
Find out in this article!
How to connect your TV to an amplifier via an optical connection (toslink)
The vast majority of televisions have a digital audio output (S / PDIF), most commonly in Toslink optical format. If your amplifier or sound bar has a digital audio input, then you can directly connect it to the digital audio output of the TV using a Toslink optical cable.
The optical connector is convenient and almost universal as the majority of televisions, AV receivers, stereo amplifiers and sound bars have one. But it is not the best way to enjoy TV sound on your home theater.
Why isn’t an optical connection ideal?
Quite simply because of its bandwidth, which is too limited to let uncompressed HD soundtracks (Dolby True HD, DTS HD MA) and immersive 3D audio tracks like Dolby Atmos and DTS:X pass through.
In addition, an optical link connection only transmits sound, while an HDMI ARC or eARc connection, as we will see below, also makes it possible to control one of the two devices with the other’s remote control (volume, mute, etc…).
How to connect your TV to a sound bar via HDMI ARC?
Introduced with the HDMI 1.4 standard, the audio return channel called ARC (Audio Return Channel) allows you to use the HDMI input of a compatible television as audio output and the HDMI output of an amplifier or sound bar as an audio input. It is thus possible to send the sound from the television to the AV amplifier or to the sound bar without adding a cable.
All you need is an
On most TVs, the audio return channel allows you to output sound in stereo but also in up to 5.1 channels (compressed). Dolby Digital and DTS are therefore supported. However, Dolby True HD, DTS HD MA, Dolby Atmos and DTS:X which require a higher bandwidth are not supported by the HDMI ARC connection.
When you establish an HDMI ARC connection between two devices, you can also take advantage of the CEC control protocol which allows them to be controlled independently via their respective remote controls. You can therefore control the volume and mute the sound of the amplifier or the sound bar with the TV’s remote control.
CEC also allows the amplifier or the sound bar to be automatically powered on when the television is turned on, and vice versa.
Finally, the HDMI ARC connection allows you to manage the image / sound shift on certain TVs (check in the TV audio settings menu).
How to connect a home cinema to the TV using HDMI eARC?
The HDMI eARC (“enhanced ARC”) function is part of the specifications of the HDMI 2.1 standard. It incorporates all the ARC features plus support for uncompressed multi-channel audio formats requiring high bandwidth such as Dolby True HD and DTS HD MA as well as Dolby Atmos and DTS: X.
Note that the HDMI eARC functionality is mandatory with the HDMI 2.1 connector, but it is found on certain TVs and certain amplifiers or sound bars with HDMI 2.0 connectors or whose HDMI connectors are not yet HDMI 2.1 certified.
The control function of connected devices (CEC) is also included and management of the delay between the image and the sound (lipsync function) becomes mandatory.
Finally, HDMI eARC technology is fully backwards compatible with HDMI ARC. One can therefore take advantage of the audio return channel between an HDMI ARC amplifier and an HDMI eARC TV, and vice versa, but with the limitations inherent to HDMI ARC.
To take full advantage of the eARC HDMI connection, it is recommended that you use an HDMI cable that offers high bandwidth. HDMI High Speed or HDMI High Speed with Ethernet certified cables are sufficient to enjoy only the audio return channel.
Premium High Speed HDMI cables, Premium High Speed HDMI with Ethernet or even Ultra High Speed HDMI cables are recommended for bi-directional connections (HDMI output with 4K / 8K images from the receiver to the TV and audio return channel from the TV to receiver).
Comparative table: Toslink optical, HDMI ARC and HDMI eARC
| Function | TOSLINK: Good | HDMI-ARC: Better | HDMI-eARC: Best |
| Cable type used | S/PDIF optical | HDMI | HDMI with Ethernet |
| Stereo compatible | Yes | Yes | Yes |
| Compressed 5.1 | Yes | Yes | Yes |
| Uncompressed 5.1 | No | No | Yes |
| Uncompressed 7.1 | No | No | Yes |
| High bandwidth & acoustic objects up to 24-bit/192kHz (ex Dolby Atmos, DTS:X) | No | No | Yes |
| Maximum audio bandwidth | ~ 384 Kbps | ~ 1 Mbps | 37 Mbps |
| Communication between devices | No | CEC | eARC data channel |
| EARC compatibility (Audio EDID, etc.) | None | CEC | eARC data channel |
| Delay correction sound/image | No | optional | mandatory |
| The TV can mute and control the sound | No | Yes (CEC) | Yes (CEC) |
| Turning on the TV activates audio devices | No | Yes (CEC) | Yes (CEC) |
| ARC backwards compatibility | No | unknown | Yes |
See also: How to connect your home cinema to your Internet TV box?
