On the rear panel of our TVs, even the most modern ones, there is often a rather strange connector. From its profile you can see a glow of red light, its shape is trapezoidal and a label indicates the presence of a connector TOSLINK or an optical audio output (digital audio out, optical).
Very little known both in the past and today, the TOSLINK port generally remains completely unused although it is good to be aware of its potential. In some cases, in fact, theoptical audio output it can really “take the chestnuts out of the fire”.
What do you mean by optical or TOSLINK audio output
The vast majority of connection cables that we use every day use electrical signals. Whether analog or digital, the signal is transmitted in the form of an electrical pulse over a conductive medium.
Unlike other cabling standards, the optical audio system uses fiber optic cables and laser light to transmit digital audio between connected devices. TOSLINK, short for “Toshiba Link“, was presented by the Japanese company way back in 1983 and was originally intended for use with Compact Disc players of the time.
Optical or TOSLINK audio output has never achieved great success for various reasons. At the time of presentation it exceeded the needs of the average user while after a few years TOSLINK found in the HDMI cable a substitute for any need.
On the other hand, HDMI it is not only simpler and more effective, because it allows you to transfer both the audio signal That video on a single cable, but also supports high resolution formats. In the case of audio, for example, we mention Dolby TrueHD e DTS HD Master Audio. TOSLINK does not allow any of this.
When does it become useful to use TOSLINK nowadays
Of course, HDMI is and will remain an irreplaceable tool. However, TOSLINK does not deserve to be thrown into “oblivion” alongside many standards of the past, which are now completely outdated.
Despite dating back to the early 1980s, TOSLINK is still capable of Support 7.1 audio and high-resolution configurations. Support for 7.1 audio suggests that the TOSLINK connection can carry up to 8 separate audio channels, typical format for 7.1 surround sound. This allows you to create asurround sound experience complete, where sound can come from multiple directions for greater immersion when watching movies, playing video games and listening to music.
While this may seem like an out-of-place observation to purists, in most consumer configurations, there is no discernible difference in terms of audio quality in situations where an HDMI cable is used and those in which a TOSLINK optical connection is used.
Connect a soundbar to your TV
The best way, indisputably, to connect a soundbar with your television, consists of using an HDMI ARC connection (Audio Return Channel).
HDMI ARC supports greater bandwidth compared to TOSLINK, which means it can transmit higher quality audio. It also allows the TV to check the soundbar through the protocol Consumer Electronics Control (CEC). With HDMI ARC it is therefore possible to use the TV remote control to control the soundbar volume and other functions, simplifying the user experience.
Thanks to HDMI ARC, the sound signal coming from TV sources (such as built-in apps or devices connected to the TV) can be turned to the soundbar without the need for a separate audio cable.
Furthermore, as we have already seen, HDMI ARC transmits not only audio but also the video signal through the same HDMI cable. This reduces the number of cables necessary and simplifies installation and connection management.
Not everyone, however, owns “flashing” modern TVs and soundbars. In these cases, HDMI ARC is not supported and optical digital audio, transferable via TOSLINK cable, is often the solution.
Sometimes you have devices that on paper should support HDMI ARC that show obvious problems with some types of audio signals (or with some sound sources). Here TOSLINK can be very useful indeed.
Perfect solution for isolating audio
In some cases you may need to separate the audio. With an HDMI cable, the operation is anything but simple: you have to use decoders, adapters and other tools to adapt the operation of the devices you have available. There are also so-called HDMI audio extractors on the market but the result may not be satisfactory.
Also because, in many cases, one could find oneself a victim of technology HDMI HDCP (High-bandwidth Digital Content Protection), a solution of DRM (Digital Rights Management) used to protect digital content from incorrect, unexpected or unauthorized use. HDCP was developed by Intel and is used not only with HDMI, but with a variety of digital video standards such as DisplayPort and Digital Visual Interface (DVI).
If you had some reason to isolate the audio signal from a digital source it is almost always much simpler to do so by equipping yourself with TOSLINK cables.
You have a nice set of speakers which you have been fond of for a long time but cannot use digital inputs because they are not present? You can use an audio converter with TOSLINK interface. In general, you can use these types of cables to “free up the audio” and free yourself from the hassles of HDMI content protection standards.
How to eliminate mass feedback hum
Il buzz own of mass return it is a phenomenon that can occur with some types of audio connections, especially when using audio/video cables connected between devices such as TVs, speakers, DVD players, game consoles and so on. This disorder can be described as a constant and annoying sound, similar to background noise particularly annoying.
This situation arises when there is a potential difference electrical power between the connected components: there is therefore a current flow through the cables. This current is the cause of electromagnetic interference (EMI) amplified and perceived as an audible hum. One of the most common causes of hum in multimedia devices is imperfection grounding of equipment, with the various cables using different circuits.
In a perfect world, we would need to track down who was responsible and fix the grounding problem. In practice, it is often possible to completely eliminate the annoying hum from your audio system by isolating the device where the problem is most evident using a TOSLINK cable.
Being about fiber optic cablesmade using exclusively plastic and glass, removes the problem of electrical conductivity which transfers the interference of the ground circuit to the speaker system.
Therefore, although HDMI has acquired the place it deserves in the management of any multimedia configuration, TOSLINK can really solve specific needs and problems that cannot otherwise be addressed.
Some additional information on TOSLINK
The TOSLINK standard has a limit in terms of maximum length of the cable. We are talking about about 10 meters although the advice is to always stay below 5 meters if possible, making sure to always use quality connection cables.
TOSLINK compatible devices take care of automatically selecting and managing the audio format supported. Those supported are as follows: PCM 2.0, Dolby Digital 2.0 to 5.1, Dolby Digital EX 6.1, DTS Digital Surround, DTS-ES Matrix 6.1, DTS-ES Discrete 6.1 and DTS 96/24 (96 kHz audio, 24 bit).
The consumer version of the TOSLINK interface has remained essentially unchanged for decades. A TOSLINK optical audio cable from the 1990s will work just like one that can still be found on the market today. There is a variant called MINI-TOSLINK which, as the name suggests, is an even more compact version.
Most TOSLINK devices consist of a port protection mechanism (sometimes a rubber plug): you need to remove this, of course, before you can insert the cable into its slot.
Opening image credit: iStock.com – popovaphoto