Optical vs HDMI—Which Should You Be Using?

By Greg Martinez / October 5, 2020
Two HDMI cables side by side

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Imagine this: you’ve just purchased a state-of-the-art home theater system that’s guaranteed to give you the movie theater experience.

You want to connect it to your big screen TV to complete the set up. But you’re in a dilemma; both gadgets have optical and HDMI ports, and you want to get the most out of your investment.

You’re torn between using optical vs HDMI cable options to pair up your toys.

Fear not; many have found themselves in this predicament but made the right choice.

In this article I’ll expound both options to help you make an informed decision.

Optical Audio Cable

An optical audio cable can be a good way of connecting components in your system.

It’s used in audio equipment to stream sound in digital format from components such as CD and DVD players, digital audio tape recorders, computers, and video game consoles to an audio/ video receiver that decodes the signal and powers your speakers.

It’s also referred to in certain circles as a Toslink (or “Toshiba Link”) cable because Toshiba originally developed it.

An excellent optical cable I use is the one from KabelDirect. You can order it in varying lengths so as to not have those useless coils near your equipment.

KabelDirekt Optical Digital Audio Cable

Admittedly this is somewhat higher quality and you could find cheaper but your sound equipment will thank you for it.

High Definition Multimedia Interface (HDMI)

We’ve all seen and used this type of cable. HDMI is a single cable solution for transferring high-definition audio and video.

It’s used in homes to connect devices such as Blu-ray players, DVD players, Xbox, PlayStation, digital TV, and Apple TV with your television. It’s actually an improvement on analog solutions that require separate audio and video cables.

HDMI is more than a physical cable and a port on the back of your TV. It’s a global standard (i.e., a set of rules) allowing high-definition electronic devices to communicate with each other.

With the right set up, HDMI can greatly improve your home theater system. The current standard carries up to 1080p high definition signals and up to eight uncompressed audio channels, sufficient for a 7.1 surround system.

To put it simply, it cuts down on both the number of cables required to connect components, and the number of remote controls needed to watch a movie in your home.

For a good example of HDMI cable, Amazon makes a decent product that’s both affordable and works with the latest standard.

AmazonBasics High-Speed HDMI Cable

NOTE: HDMI and optical cables both transmit multi-channel audio signals from one device to another. The glaring difference in terms of their functionality is that the optical cable doesn’t transmit video.

But missing out on digital video isn’t something you’ll ordinarily miss in your home theater system as you already have video from your HDTV.

Materials

So, our comparison of optical vs HDMI would be incomplete without delving into their material construction:

  • Like most electronic cables, HDMI cables are made primarily of copper because of its high electrical conductivity, ease of production, and low cost of production. This makes it the most popular non-precious metal for electronic use. The only downside is its susceptibility to electromagnetic interference.
  • Optical cables are made of fiber optic cable strands that transmit signals through light instead of electric current, making them impervious to outside interference. They are, however, relatively expensive to manufacture in comparison to copper cables.

Optical cables will function well enough for most home entertainment systems. They should comfortably support surround sound of up to 5.1 channels.

But they’re not always the perfect solution for more complex sound systems.

They don’t have the bandwidth to carry the lossless versions of Dolby True HD, Dolby Digital Plus, and DTS-HD Master Audio, which are increasingly popular in home entertainment equipment like Blu-ray Disk players.

They also can’t carry more than two channels of PCM (Pulse Code Modulation).

Most of what’s transmitted over optical cables is digital in two main formats: Dolby Digital Format and PCM.

Dolby Digital Decoders

These are designed to not transmit signals that are less than perfect. In fact, they’ll cut out the entire signal rather than risk damage to the speakers if they detect any anomaly.

Therefore, bandwidth is a significant limitation for someone who has invested in an advanced, powerful sound system.

This digital decoder by Prozor will convert digital audio to analog, for instance:

PROZOR Digital to Analog Audio Converter Support Dolby/DTS Decoder

Care of Optical Cables

Optical audio cables have to be handled carefully; they appear sturdy like other cables but are actually made of delicate fibers and wires.

They’re also susceptible to breakage when performing generic everyday acts such as bending and twisting.

Maybe your audio set up requires you to bend cables to follow the outline along a wall. If the optical audio cable stops working suddenly, the bend could have caused a break in the cable.

The breakage occurs inside a protective sheath that usually covers the cable, so you may not see it with the naked eye. When this happens, there’s no option but to buy a new cable.

Connecting Optical Cables

Optical cables connect to other components via a special connector, which is very sensitive and should be inserted carefully. If these are tightened too much, they’ll most likely break but on the other hand, if it’s not inserted properly, the components won’t connect.

As much as optical audio cables won’t experience interference, they have a high attenuation of light, limiting their effectiveness to between 30 and 60 feet for the more common plastic ones.

There are less common glass or silica optical audio cables that can push this tolerance up to 100 feet perhaps, but these are relatively expensive and less popular.

HDMI Cables

HDMI cables, on the other hand, have a maximum run range of 50 feet. This is caused first of all by the interference we referred to earlier.

Secondly, HDMI signals use very low voltages (5 volts), which hinders how far a signal can be transmitted. The signal will generally lose clarity or degrade after 50 feet.

HDMI gives you better quality audio than you’ll get from an optical cable; which makes it very popular.

It also enables CEC technology that allows the use of the same remote across all your HDMI connected devices.

There’s a catch to enjoy such HDMI benefits, though: all components of your home theater system must be compatible with these functions.

Optical can be a good alternative when you have such compatibility issues. It’s also a better choice for longer cable runs, like wiring your entire home’s audio system.

Optical vs HDMI: Conclusion

Both technologies have their strong points. An HDMI cable will give you the best audio quality while supporting all the latest audio formats. It’ll also let you enjoy using the remote across all compatible devices.

Optical cables give you decent sound and are immune to interference, and are thus suitable for longer cable runs.

So the best cable for you will be dictated by what you need and the equipment you have at hand.

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