Best audio technology: Toslink, HDMI ARC and eARC

Digital audioWhen we connect a new soundbar or home theater system to the TV we need to choose a connection cable that maintains the audio quality of the original source, particularly if we really love watching movies via Blu-ray, DVD, or via streaming apps like Netflix or Amazon Prime Video. While the choice may seem obvious, the technology has advanced so far over the last few years that it has made one of the most famous digital connection methods such as the optical cable (also called S / PDIF or Toslink) obsolete, in favor of the new HDMI. ARC (and its most recent evolution, namely HDMI eARC).In this guide, we will show you the differences between Toslink, HDMI ARC, and eARC and what is the best technology for digital audio, so as to be able to benefit from multimedia contents at a much higher than average quality compared to analog connections (now totally obsolete for multimedia contents available to cinema and TV series enthusiasts).

READ ALSO -> Place the 2.1, 5.1, and 7.1 home theater surround sound speakers

Which cable to use for digital audio output

The technologies that we will examine in the following chapters are present on practically any soundbar, Hi-Fi stereo system, or home theater amplifier, we just need to get the right cable and make the connection as indicated. For each technology, we will show you strengths and weaknesses, complete with a link to buy a high-quality cable to make the chosen audio connection.

Connessione Toslink o S/PDIF

The oldest and most compatible digital audio connection is the optical audio output, present behind the televisions also with the writings Toslink OUT, Optical DIGITAL OUT, Audio Digital OUT O S/PDIF OUT.


This technology uses optical fiber and a red light beam, capable of carrying the audio signal digitally through a succession of light pulses. The digital optical output allows for excellent audio quality in all scenarios and is compatible with stereo audio and compressed digital audio (Dolby Digital 5.1), but it has very obvious limitations: it is not possible to control the final playback device (soundbar or system) with the TV remote control, forcing us to use the device’s dedicated remote control to be able to raise or lower the volume and turn it on or off; with the optical audio output we cannot even take advantage of modern technologies such as automatic sound synchronization with the video being played (Lip Sync) or Dolby Atmos / DTS: X.

However, it remains the most compatible technology even on old TVs or Hi-Fi systems with a few years on their shoulders. To make the connection just insert the Toslink cable in the appropriate optical ports: on TV we must use the port Digital OUT or similar, while on the breeding plant we have to find Digital IN O Optical IN; after the connection let’s go to the TV settings, open the audio menu and set the optical audio output for listening. If we want to use this technology we advise you to focus on a quality cable such as theiVANKY Optical Digital Audio Toslink Cable 1.8 m, available on Amazon for less than 10 €.

HDMI ARC connection

Modern technology for making digital audio connections is the HDMI ARC, present on virtually all televisions produced after 2009.


With this technology, we use a dedicated HDMI port to send the audio “backward” compared to the standard HDMI stream (which we remember only goes towards the TV), exactly as the name of the technology suggests (ARC stands for Audio Return Channel or Audio Return Channel). Taking advantage of the HDMI we will get a high audio quality, we keep the support for Dolby Digital 5.1 e we will remedy all limitations of optical output: thanks to CEC (another technology integrated into HDMI) we can control the output volume with the TV remote control and switch on / off the soundbar or the system together with the TV, greatly facilitating the usability of the contents. Optionally HDMI ARC also supports Lip Sync, but only if it is provided for by the settings of the TV and the chosen system. The only limitation of this technology is the perennial occupation of an HDMI port, which will reduce the number of HDMI devices we can connect to the TV.

It is currently the reference method for connecting soundbars and home theater systems, as it is simple to set up and provides complete control with a single remote control. To make this connection we identify the port on the back of the TV HDMI ARC (not all HDMI ports on the same TV are ARC compatible) so we use a standard HDMI cable to connect this specific port to the port HDMI ARC IN soundbar or system in use. If we want to use a quality cable to make this connection we recommend that you buy the cable Amazon Basics – Ultra HD HDMI 2.0 High-Speed ​​Cable with Audio Return Channel, 1.8m, available on Amazon for less than 10 €.

READ ALSO: HDMI 2.1 ARC: what it is and how to best use it

HDMI eARC connection

The most advanced technology for connecting audio devices is HDMI eARC, which as the name suggests is the evolution of the previous HDMI ARC technology and is present on Smart TVs on the market in recent years.


This technology makes it possible to obtain audio at the highest possible quality, with support for Dolby Digital 5.1 and 7.1 audio, support for uncompressed multichannel audio, and support for more powerful audio codecs such as Dolby Atmos e DTS:X. The incomparable sound quality also adds the mandatory support for Lip Sync, so as to always have the audio synchronized with the video.

HDMI eARC retains the benefits of ARC in single remote control and is backward compatible with HDMI ARC ports on older devices. Obviously, it also maintains the disadvantage of traditional ARC, which is to always keep an HDMI port occupied for audio. Making the connection is simple: we identify the HDMI eARC port behind the TV and we use a high-speed HDMI cable to connect to the port HDMI eARC IN on the soundbar or home theater system.

We cannot use a traditional HDMI cable for this technology, but we must use the latest generation HDMI 2.1 cable, the only one able to guarantee support for all the features described; if you use a simple HDMI cable we will only be able to take advantage of the traditional HDMI ARC, failing to support the new features. The best cable we can use for eARC HDMI is the Snowkids HDMI Cable 8K @ 60Hz Braided High Speed ​​48 Gbps, available on Amazon for less than € 20.


For fans of cinema and TV series at home and fans of new audio technologies, it is time to update: the optical cable can be permanently retired, replaced with great results by the HDMI cable with the return audio channel, which allows you to achieve extremely high-quality levels and providing the most requested feature by all fans, namely universal control via a single remote control (that of the TV.

If we are going to buy a new TV, make sure it supports HDMI ARC or better yet HDMI eARC so that we are ready to connect a soundbar or home theater system in the future. To learn more we can also read our guides How to choose and buy the best Smart TV e How to choose the right HDMI cable.

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