What Is a Coaxial Cable?
A coaxial cable is a shielded copper cable used to transmit electrical signals, including digital audio signals between hi-fi components.
In home audio systems, coaxial cables are commonly used for digital audio connections between devices such as CD players, streamers, TVs, and external DACs.
How does a coaxial cable work?
A coaxial cable consists of four main layers:
- Central conductor – Carries the signal
- Insulating layer – Surrounds the conductor
- Metal shielding – Protects against interference
- Outer jacket – Protective covering
The shielding helps prevent electromagnetic interference (EMI), making coaxial cables suitable for digital signal transmission.
What is digital coaxial audio?
Digital coaxial audio uses a 75-ohm coaxial cable with RCA connectors to transmit digital audio data.
Unlike analogue RCA cables, which carry variable voltage signals, digital coaxial cables transmit encoded digital data.
Coaxial vs optical (TOSLINK)
Coaxial
- Uses electrical signal over copper
- Typically 75-ohm impedance
- Physically robust
Optical (TOSLINK)
- Uses light transmission
- Immune to electrical interference
- More fragile cable construction
Both formats transmit digital audio. In most home audio setups, audible differences are minimal if the signal is transmitted correctly.
What audio formats does coaxial support?
Digital coaxial connections typically support:
- PCM stereo audio
- Dolby Digital
- DTS surround sound
Like optical connections, coaxial digital cables do not usually support higher-bandwidth formats such as Dolby TrueHD or DTS-HD Master Audio.
Is a coaxial cable the same as an RCA cable?
They may look similar, but they are not the same.
A digital coaxial cable uses RCA connectors but is specifically designed with 75-ohm impedance for digital transmission. Standard analogue RCA cables are not always suitable substitutes.
When should you use a coaxial cable?
A coaxial cable is commonly used when:
- Connecting a CD transport to an external DAC
- Linking a streamer to a DAC
- Connecting certain TVs to audio systems
Frequently Asked Questions
Is coaxial better than optical?
Both transmit digital audio data. Performance differences are typically minimal in standard home audio systems.
Can coaxial carry surround sound?
Yes. Coaxial digital cables support Dolby Digital and DTS surround formats.
Does a coaxial cable affect sound quality?
Since the signal is digital, sound quality depends primarily on the receiving device's DAC, provided the data transmission is error-free.
In simple terms
A coaxial cable is a shielded copper cable used to transmit digital audio between hi-fi components using electrical signals.