Coaxial and Optical Digital Audio Cables Differences

Your equipment dictates which set of cables to use

Coaxial and optical cables are used to make audio connections between a source such as a DVR, Blu-ray Disc player, game console, and other components such as an amplifier, receiver, or speaker in home entertainment setups. Both cable types transfer a digital signal from one component to the other.

Not all audio equipment supports both options, so you may not have a choice, but if you do, you want to make an informed choice about which cable will perform best in your home. The answer varies depending on the source you ask, and many professionals agree that the difference in performance is usually negligible. To make the most informed decisions, some basics about coaxial and optical digital cable connections are useful to know up front.

Illustration of a coaxial digital audio cable and an optical digital audio cable
 Lifewire / Tim Liedke

Both cables support 5.1 surround sound systems with a difference in sound quality that is nearly indistinguishable.

Coaxial Digital Audio Cables

A coaxial (coax) cable is a shielded copper wire that is manufactured to be rugged. It is a single wire that can transfer a signal, unlike other wired components such as speakers. Coaxial cables do not require being connected in a specific orientation. Each end of a coaxial cable uses familiar RCA jacks, which are reliable and stay firmly connected.

Coaxial cables may be susceptible to radio frequency interference (RFI) or electromagnetic interference (EMI). If any existing hum or buzz sound problem is present within a system, such as a ground loop, a coaxial cable may transfer that noise between components. Coaxial cables are known to lose signal strength over long distances, which is usually not a concern for the average home user. However, if distance is an issue, then optical cables are the better choice.

Optical Digital Audio Cables

An optical cable (also known as Toslink) transfers audio signals via light that is beamed through a glass or plastic fiber optic medium. The signal that travels through the cable from the source must first be converted from an electrical signal to an optical one. When the signal reaches the receiver, it undergoes a conversion to an electrical signal again.

Optical cables are not susceptible to RFI or EMI noise or signal loss over distances, because light does not suffer from the resistance and attenuation that occurs in copper cables.

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.

Your Choice

The decision about which cable to purchase is most likely based on the type of connections available on the electronics in question. Not all audio components can use both optical and coaxial cables.

Some users argue a preference of coaxial over optical, due to a presumed improvement of overall sound quality. While such subjective differences may exist, the effect is likely subtle, notable only with high-end systems, if that. As long as the cables themselves are well made, you should find little performance difference between the two types, especially over short connection distances.

HDMI cables transfer both audio and video. If your equipment supports HDMI connections, this advanced option provides uncompressed audio to eight channels for 7.1 surround sound systems, and it handles 3D and 4K content. As HDMI cable prices have come down, they have replaced optical and coaxial cables in many home entertainment systems.