SPDIF Coaxial Cable– How SPDIF Coaxial Cables Actually Work


When working with audio and digital hi-def systems, having a SPDIF coaxial cable is a must.

These cables connect audio consumer equipment like home theatre systems and TVs, allowing them to output audio from one another.

Whether you are, this information may come in handy.

Learn how spdif coaxial cables work, the interchangeability factor between digital and analog cables and more.

Expand your knowledge in the area and have fun enjoying the beauty of high-fidelity audio in any equipment available.

Table of Contents

1. Understanding SPDIF

Understanding SPDIF

Spdif is a digital audio protocol that transfers compressed digital audio signals between various pieces of equipment. It then turns the compressed sound from the source into a surround sound. The protocol uses an amplifying receiver to make it happen.

As it’s based on the AES3 audio protocol, spdif does the same AES3 does for professional studio audio equipment. However, spdif made using RCA and TOSLINK connectors cheaper than the XLR ones AES3 devices commonly use.

Although SPDIF is a digital protocol, it is also physical, as it uses cables to carry its function. These cables are coaxial or optic fiber, yet, SPDIF coaxial cables with RCA connectors are more common than others.

Their distinctive orange-colored connectors allow people to tell RCA coaxial cables from cables used for composite video.

Jitter, on the one hand, is unavoidable. Yet, this timing error in the audio signal can augment or decrease according to the cable type.

Coaxial and optic fiber send audio signals in the same way.

But, optic fiber cables tend to show higher jitter than coaxial cables when reproducing the transferred data.

This jitter may cause the loss of one or more bits.

2. Digital Audio Connection for S/PDIF signal

Sony/Philips Digital Interconnect Format coaxial cables come in different types and materials for different uses.

This makes learning to discern between coaxial, optical, or HDMI and which one to choose mandatory.

Coaxial audio cables

These are the most common spdif cables known to humanity but are not the only ones.

They have a conducting copper shield surrounding an insulator, which covers an inner conductor core.

Coaxial cables use RCA jacks and plugs to send the audio signals.

Cables have one jack for digital transmission and two jacks for analog transmission.

Optical audio cables

Optical audio cables

Optical fiber cables use light instead of electricity to transfer the data.

People use them to transfer DTS surround sound and Dolby Digital audio from a source to a DAC with excellent results.

But, although coaxial cables are better than optical ones, these still lack the bandwidth to send HD audio signals.



HDMI has the best of both worlds, as it carries HD audio and video signals using one single connection.

This allows it to support more audio channels and lossless audio formats for clearer and high-fidelity audio playback.

That means that this technology improves and evolves at a rapid pace with no current rival.

Which one to choose


Choosing one or the other depends on what you like or the audio equipment you own.

Whether digital or analog, coaxial has a raw and better audio quality than its optical counterpart.

Nonetheless, HDMI cables offer a comfortable and quick way to transfer audio, as most equipment today has an HDMI connection.

3. Analog Audio Connection

Purists consider analog audio better than digital audio.

That includes everything from the recording process to the transmission and final reproduction of it.

These analog audio connections use composite RCA cables that transfer two sides of the same data to complete the stereo sound.

SPDIF Coaxial Cables

Composite RCA cables

A common RCA connector usually transmits audio and video using three RCA jacks.

However, composite RCA cables used for an analog audio connection carry the audio’s left and right stereo channels.

This type of cable does not support HD content of any kind.

Introduced in the 1930s, people used RCA connectors to join phonograph turntables to a radio receiver.

Nowadays, people use these cables in almost any audio component or equipment like DVD, VCD, and CD players.

These cables come with white and red-colored jacks, white for the left/mono channel and red for the right channel.

Difference between coaxial audio cables and composite RCA cables

There are a few main differences between the two types of audio cables. 

First, both carry audio signals; spdif coaxial cables are digital, and composite RCA cables are analog counterparts.

Second, coaxial cables being a digital transferring option, transmit 5.1-channel audio with high fidelity. Composite RCA cables cannot do this.

Third, coaxial cables shield from external noise, making it a great cable for RF usage, while RCA doesn’t.

Fourth, people still use coaxial cables, while most equipment using RCA cables is now obsolete. 

4. Interchangeability between digital cables and analog cables

SPDIF Coaxial Cables

While all RCA coaxial cables may look, the same digital and analog versions exist.

Each impedance is different (around 50ohm on the analog and about 75ohm on the digital ones).

Said impedance factors make the signals captured by these cables distort or get damaged.

When connecting your DAC, the right cable is best to ensure proper performance.

Although both cables may work by substituting each other, following the natural flow of things is recommended.

Analog devices should go with analog cables, and digital devices should go with digital ones.

However, spdif coaxial cables can work on many analog devices and vice versa when using high-quality cables.

Avoid cheap and flimsy-looking RCA or coaxial cables to ensure the correct functioning and data transmission.


There is no doubt that you have a clear picture of the audio connection.

And as you can see, coaxial cables can support good audio quality, whether digital or analog.

Take the right actions to purchase the cables that best suit your needs.

We are here to provide the perfect coaxial cable assemblies with connectors.

So, if you have any questions, feel free to contact us.