HDMI ARC Vs Optical – Which Is The Best Connection?

If you’re connecting a games console or Blu-ray player to your TV or gaming monitor, the connection of choice is simple – HDMI. However, when it comes to audio devices such as soundbars and AV receivers, the choice isn’t so simple.

One of the big questions we get asked around here is HDMI ARC or Optical audio, which is best for my audio requirements? And for that reason, we’ll be showcasing all the major differences that separate the two very capable audio transfer interfaces.

So, let’s waste no further time and dive straight into it!

What Is HDMI ARC?

HDMI, or High Definition Multimedia Interface, is the most popular consumer HD signal for transferring high-definition video and audio from a device to your TV or monitor. It’s the most widely used format for most consumer goods and is widely used in the commercial AV sector as well.

Several versions of HDMI have been developed and released since the technology was originally released, with the latest HDMI 2.1 version offering up enough bandwidth to allow console gamers to play in 4K @ 120Hz.

But what is HDMI ARC?

ARC stands for Audio Return Channel and connects your TV to your sound system via a single high-speed HDMI cable – eliminating the need for an additional composite or optical audio cable.

What Is Optical Audio?

Optical audio, or TOSLINK, is a standardized optical fiber connector system that allows the transfer of audio from a device to an AV receiver or soundbar. It is most commonly used in consumer audio equipment such as CD/DVD players, games consoles, and DAT recorders, allowing the transfer of audio from one device to an output source.

It was developed back in the ’80s by Toshiba and became hugely popular in the ’90s – quickly recognized as the easiest way of getting Dolby Digital and DTS from your cable/satellite box to your AV receiver.

HDMI ARC vs Optical – The Basics

Ultimately, HDMI ARC and optical audio both offer the same service – the high-speed transfer of audio from one device to an AV receiver or soundbar. They both allow the transfer of multi-channel audio, including Dolby Digital. Both HDMI ARC and optical offer better performance when compared to the aging analog format (red and white cables). Having said that, the major difference that separates the two interfaces is Optical’s lack of ability to transfer video signals. However, thanks to the nature of HDMI ARC, that isn’t really an issue for optical audio.

Alongside the lack of video transfer, optical audio and HDMI ARC also differ in the material construction they come equipped with. HDMI cables are primarily constructed using copper, which has been fairly standard across any electronic cable. Copper is a cheap manufacturing material and has been used within the consumer market for centuries now. However, it does have a small downside – electromagnetic interference.

Optical audio cables, on the other hand, are created using fiber optic strands – which when broken down, are made of glass. The main downside to this particular manufacturing process is cost. As the name suggests, optical transmits a signal via light instead of an electrical signal, meaning they don’t falter to electromagnetic interference.

HDMI ARC vs Optical – The Differences

So, whilst we’ve touched upon material makeup and potential interference, that still doesn’t tell us what audio and visual differences the two interfaces provide – if any. So, let’s explore that in a little more detail.

Audio Differences

Let’s be honest, for most entertainment systems, either optical audio or HDMI ARC are going to do the job just fine. They both support up to 5.1 multi-channel audio, which is more than enough for most soundbar requirements. However, if you’re the sort of person that has/or plans to invest in a 7.1 channel audio system, the optical audio cable simply won’t cut it.

Annoyingly, Optical audio cables are limited to 5.1 channel audio. Furthermore, the aging technology doesn’t support newer audio codecs such as TrueHD, DTS HD, or Dolby Digital Plus – and that’s a real negative when it comes to getting the most out of your sound system.

To really get the most out of your sound system in this day and age, you’ll need to make use of an HDMI ARC cable. HDMI ARC is incredibly versatile, supporting almost every type of audio format. It supports Dolby Atmos, Dolby Digital Plus, TrueHD,  and DTS HD – providing superior sound quality when compared to older codec options.

However, and like optical audio, the HDMI ARC cable won’t support 7.1 channel audio either. For that, you’ll need to invest in an eARC HDMI cable – with the ‘e’ standing for enhanced. This standard of HDMI is capable of transferring 7.1 channel audio signals for the more advanced home sound system. Alongside 7.1 audio, eARC also offers greater overall bandwidth.

Am I losing Audio Quality By Using Optical Over HDMI ARC?

In short, yes. However, it’s a little more complicated than that. If you have a sound system that doesn’t offer high-end audio, then optical audio will probably be more than enough for your need. However, if you’re using one of the latest audio codecs – mentioned above – you’ll definitely be experiencing worse sound quality.

Most modern TVs – especially the most expensive options – output compressed sound at a lower than the input. This effectively limits your sound quality regardless of whether or not you’re HDMI ARC. That being said, making use of HDMI eARC – an interface that utilizes ethernet technology – allows you to transfer the same quality audio as the input source. In other words, using an HDMI eARC cable allows you to enjoy rich, uncompressed audio without any annoying latency issues.

Video Differences

As you’ve probably guessed, video quality only applies to the HDMI standard in this scenario. However, it’s still worth mentioning as different versions of HDMI offer completely varying levels of performance. For example, if you want a 4K video experience, HDMI 2.0 will be more than enough for your needs. That being said, when it comes to gaming, you will be limited to 60hz – not great for the next-gen console players.

HDMI 2.1, the latest standard of HDMI, offers up enough bandwidth to allow gaming at 4K in 120hz. It even provides enough data transfer to view 8K at 60 frames per second – a huge jump from HDMI 2.0.

What About Cable Length?

Cable length is actually hugely important when it comes to audio systems – mainly because audio/video transfer can be lost along the way. For most home users, any cable around 2m will probably offer the best performance. Most AV Receivers or soundbars are placed directly under the TV, meaning the cable only needs to travel roughly half a metre anyway. That being said, for more elaborate stereo setups, you may need to run a cable several meters – if not more.

Before we discuss the limitations of both interfaces, it’s worth mentioning that, when setting up your audio system, you should always utilize the smallest cable possible. As we said before, audio and video signals can run into interference with longer cables – with the chance increasing as cable length goes up. Furthermore, if you’re making use of multiple cables for different speakers, you should always use the same length cable – for the same reason as above. This will also make the AV receiver work harder and can lead to interrupted/laggy audio output.

An HDMI cable is limited to a maximum length of roughly 15 metres. One of the reasons for this is the interference that we just spoke about above. Secondly, the HDMI signal makes use of an extremely low voltage (5V) – and as a result, cables can only carry this signal so far. Ultimately, at these voltages, after 15 metres the signal will start to degrade quite exponentially.

An Optical cable is limited to a maximum length of roughly 10-30 metres. As no material is completely transparent, the light source used in optical cables will begin to degrade after 10-30 metres. This will lead to interference, latency, and potential interruption during audio experiences.

HDMI ARC Vs Optical – The Bottom Line

So, what’s the best for my needs? Well, as a general consumer who is using a soundbar or AV receiver, you have to go with the HDMI ARC option. Simply put, an HDMI ARC connection will offer up the best sound quality and supports high-performance audio codecs like Dolby Atmos, Dolby Digital Plus, TrueHD,  and DTS HD. Furthermore, HDMI ARC will also enable CEC technology as well – allowing you to utilize the same remote across multiple devices or systems.

Having said that, there’s always the old compatibility issue. Many modern TVs are limited when it comes to the number of HDMI outputs they have to offer. So, in the case where all HDMI ports have been taken, the easiest resolution will be to make use of an optical audio cable. This will still allow a decent audio performance and should supply enough quality to please most home systems.

Final Thoughts

So, there you have it, our complete rundown of HDMI ARC vs optical audio interfaces. Ultimately, it all comes down to your needs and what kind of audio system you are using. If you’re using an elaborate home audio system, chances are you’ll need to use the more advanced HDMI ARC (or eARC) cable. That being said, for individuals that are lacking input ports, the optical audio cable still offers good performance and should suit most home-consumer needs.