Coaxial vs. Optical Digital Audio Cables

Coaxial and optical cables are used in home entertainment systems to connect an audio source (such as a set-top box, Blu-ray player, or video game console) to a component (such as an amplifier, audio receiver, or speaker system). Both types transfer a digital audio signal from one device to the other.

Not all audio devices support both coaxial and optical cables, so you may not have a choice. If you do have a choice, it still may not matter much. Many experts say the difference in audio quality and performance is negligible. That being said, it's a good idea to learn the basics about coaxial and optical cable connections.

Coaxial Digital Audio Cables Pros and Cons

A coaxial (coax) cable is a shielded single copper wire used in many audio interfaces and connections, although it is not quite as common as optical connections in modern sound systems. While coaxial cables promise theoretically superior sound—by means of a greater bandwidth—the difference probably isn't noticeable to most people.

Coaxial cables look and operate much like traditional RCA jacks, which are favored for their ruggedness and durability. They may be susceptible to radio frequency interference (RFI) or electromagnetic interference (EMI). If any existing humming or buzzing is present within a system, a coaxial cable may transfer that noise between components. Coaxial cables are known to lose signal strength over long distances, which is not a concern for the average home user. However, if distance is an issue, then optical cables are the better choice. Finally, coaxial cables do not have enough bandwidth to support high-end surround lossless formats like Dolby TrueHD and DTS-HD Master Audio.

Optical Digital Audio Cables Pros and Cons

Optical or "Toslink" cables use light to transfer audio through optical fibers. Audio signals must be converted from an electrical signal to an optical one before traveling through the cable. Once the converted signal reaches the receiver, it is converted back into an electrical signal.

Optical cables tend to be more fragile than their coax counterparts; optical cables can't be pinched or bent tightly, for example. The ends of an optical cable use an odd-shaped connector that must be inserted correctly, and the connection is usually not as tight or secure as a coaxial cable's RCA jack.

Like coax cables, optical cables do not have enough bandwidth to carry lossless or uncompressed audio formats, such as those used on Dolby surround sound systems.

Your Choice

The decision about which cable to use should be based on what is available to you. Not all audio components can use both optical and coaxial cables, and HDMI is increasingly the standard for most home entertainment systems and components.

Some users prefer coaxial over optical because it can support slightly higher resolution audio, but those differences are likely only noticeable on very high-end sound systems, if at all. As long as the cables themselves are well made, you should find the sound they produce to be indistinguishable.