If all you’re looking for is basic sound output from your speakers, it doesn’t matter what connections you use. However, if you’re looking for quality in your home audio system, the HDMI ARC vs. Optical cable debate becomes far more relevant.
Here’s everything you should know about these two types of connections, including how they work and when to choose one over the other.
What Are HDMI ARC Cables?
HDMI ARC connections have an extra component known as an audio return channel that allows them to transmit audio alongside their video. You can’t use just any connections, though. You need both ports and cables that are ARC-compatible.
HDMI ARC cables use a traditional copper wire inside of a protective casing. This means the cables are affordable and easy to find, although they are subject to electromagnetic interference, and low-quality production can significantly worsen the cable’s lifespan and performance.
Things like radio frequencies, microwaves, lights, and power lines can all cause electromagnetic interference. It’s hard to move or stop some sources of these, so the location of your home theater is typically what determines if this is relevant.
HDMI ARC cables have a maximum effective range of 50 feet without extension systems. That’s not a problem if you’re putting your sound system right next to your audio source (usually a television), but it can be an issue if you’re routing cables around your room to reach distant areas.
These cables support almost any audio format your TV can output, which means they’re extremely compatible with other systems as long as there’s an ARC port on each end. The primary limit is that regular ARC cables don’t support 7.1 surround sound. For that, you’ll need the enhanced eARC cable, but only a few devices currently support that.
HDMI ARC cables are the only option here that also transmits video. How much video you can transfer depends mainly on the cable. An HDMI 2.1 cable is good enough for almost any household setup, allowing up to 120 frames per second in 4K resolution.
Outside of all that, HDMI ARC has one significant advantage over Optical in that it lets you connect other devices somewhere besides your television and have the input travel to the TV. For example, you could link a Blu-Ray player to your soundbar, then use HDMI ARC to transfer the video and audio to the television before the audio goes back to the soundbar to play.
This can reduce the total number of cables you need, providing a cleaner and simpler appearance. It’s particularly helpful if it’s hard to access the ports on your television and you want to use something more accessible for switching cables.
What Are Optical Cables?
Optical cables, which are also known as Toshiba-Link or TOSLINK after their original manufacturer, are the primary alternative audio output option that most people have access to on their televisions.
This format has been around since about 1983, and the fact that it’s still in use says a lot about its practicality. More importantly, Optical cables also have a lot of compatibility. Practically every audio system made over the last few decades supports Optical connections, but only a few modern systems allow HDMI ARC.
If you don’t want to replace existing audio gear, Optical cables may be your only choice.
The cables themselves use fiber-optic strands, which is the same technology used in many high-speed internet cables. However, rather than transmitting basic data, these cables use pulses to convert audio signals into pulses of light and transfer them to the receiver.
The maximum length for Optical cables depends on their construction quality. Higher-quality cables can reach about 99 feet, while lower-quality cables may only work up to 33 feet before the signal starts degrading. The main reason there’s a length limit is that no material is perfectly transparent, so light can only travel so far in these cables before it gets deflected.
Optical cables generally support up to 5.1 surround sound but not 7.1 setups. Further, Optical cables don’t support many newer audio formats like Dolby Digital Plus. That’s a significant problem if you want to get the latest and greatest audio output from modern devices.
Also, since the signals are light-based, Optical cables are immune to electromagnetic interference that can render HDMI ARC audio distorted or even unusable. Optical might be your only realistic option for getting an audio quality you can accept.
HDMI ARC vs. Optical: A Summary
Optical cables are the older format, existing on most devices since the mid-1980s. They’re highly compatible with different devices and work well for audio up to compressed 5.1 surround sound. High-quality optical cables work over longer distances than HDMI but don’t support the newest audio formats or transfer video data.
HDMI ARC cables are much newer, so they aren’t anywhere near as compatible with older devices. They’re also subject to electromagnetic interference in some areas, but they support far more audio formats, and the enhanced version will offer even more support in the future.
Ultimately, HDMI ARC is the better format in most situations if your devices are compatible. However, both formats are perfectly suitable for regular audio and the difference is only truly meaningful with advanced setups.
Deciding Between The Formats
Here are some more things to consider for the HDMI ARC vs. Optical connection debate in your area.
The first and most obvious consideration for picking cables is device compatibility. Optical is easily more compatible than HDMI ARC. This is less of a debate and more the natural result of having a format that’s several decades old and has worked outstandingly well across that period.
If you have anything but the oldest audio devices, it probably supports Optical. We can’t say the same for HDMI ARC, which has only been around since about 2009. It’s not brand-new, but many people still have and use older audio systems instead of replacing them all the time.
There’s no point in choosing a cable that doesn’t work with your devices. You can get a converter that splits HDMI ARC audio into HDMI video and Optical audio, but the Optical cable still won’t work with certain newer audio formats.
Most devices that support HDMI ARC also support Optical, so the question here is whether you can use the advanced format or not. If you can, you should. If not, you’ll need to settle for the older format or upgrade your equipment.
The next major consideration is the number and placement of speakers. Both HDMI ARC and Optical cables support 5.1 surround sound setups, although Optical systems may need to compress the audio a little. That results in a slight loss of quality, but not so much that it’s distracting for most people.
However, only enhanced ARC cables support 7.1 audio.
Beyond the number of speakers, we also need to consider those locations. As mentioned above, HDMI ARC only works well up to 50 feet, after which we start getting significant loss in signal quality. This won’t be an issue in a small living room or if you’re using a soundbar, but if you’re making a large home theater, you could easily exceed that limit.
The important thing to remember here is that it’s best to use the same type of cable as much as possible. Otherwise, things might not work at all. This is why you should measure the expected distance for your cables when deciding how to configure your home audio system.
Are There Any Other Types Of Audio Cables?
Yes. HDMI ARC and Optical cables are the best options for most people, but they’re not the only choices on the market. While most people won’t want or need the options below, we include them here for reference.
Stereo RCAs were the standard audio format for many years, and you’ll still see them on some older devices. These are distinguished by their red and white paired design, representing left and right audio. As the name implies, these cables exclusively produce two-speaker stereo sound and nothing else.
Despite their age, Stereo RCA cables are surprisingly good for many audio formats. Notably, they allow for lossless transmission in most cases, which is generally better than compressing or losing audio through digital formats.
The major limit on using Stereo RCA is the limited number of speakers. You might be able to get around this with a box that takes the RCA and changes it to something you can send to more speakers, but that rarely works out too well because the source only specifies two speakers.
Most high-quality home audio systems are at least 5.1 speakers these days, and Stereo RCA simply can’t keep up with that.
Coax Digital S/PDIF
Coaxial cables are another common alternative for speaker setups. Notably, this is the type of cable that usually brings television signals into houses, complete with both high-quality audio and video.
A good coaxial cable can carry six channels of audio, which is suitable for common 5.1 surround sound setups. However, since this is a digital signal, you may see a little bit of quality loss compared to lossless transmission formats. Most people won’t notice enough of this to be bothered by it, but it can happen.
Digital coaxial cables are also available in different sizes, and this is where picking one can start to get confusing. Generally, thicker coaxial cables have less signal loss than thinner cables, so you can run them over longer distances while maintaining quality. Some coaxial cables are only viable over 6 feet, while others can work well across a room.
How Long Should My Audio Cables Be?
Always try to keep your audio cables as short as possible, even if this means you have to trim the wires. The main reason for this is signal loss as data moves over the wire. Signal loss occurs regardless of the type of wire you’re using, although for different reasons.
Electrical connections have impedance from the physical wiring that reduces the signal strength. Essentially, it takes energy to push a connection down a wire because the wire pushes back against that.
Optical cables also have signal loss because there are no perfectly transparent materials useful for fiber-optic cables. The further a cable goes, the more signal loss we can expect.
Even so-called “lossless” connections will lose some of their quality if the cables are too long. They’re fine for short distances, but the longer the cable goes, the worse things will get.
Factors outside the wires can cause loss, too. Electromagnetic interference and heat are common problems, so it’s important to be sure you put all of your cables in a well-ventilated area.
The good news is that most home audio setups aren’t big enough to reach the practical limits of wires. Even if you’re hitting that limit, you can get around the issue of cable lengths by using an audio amplifier system. This essentially adds electricity to a signal or duplicates the signal by starting it over again, allowing you to extend your cables to any length you need.
Planning For The Future
One final consideration for the HDMI ARC vs. Optical debate is what you plan to do in the future. It’s usually a bad idea to invest exclusively in older technology, only to have to throw it out as new wires and formats emerge.
Everything becomes obsolete eventually, but HDMI ARC is more than just a newer format. It’s fundamentally better than Optical for carrying high-definition signals, and chances are we’ll see far more manufacturers focusing on HDMI ARC and eARC in the future.
Optical probably isn’t going away as a format anytime soon, but it’s no longer the option of choice for most people.
To put it another way: Optical is good if you want to use devices from the past, while HDMI ARC is better if you want to use devices coming out in the future. Only you can determine whether backward or forwards compatibility is more important for your home audio system.