HDMI ARC vs Optical: What are the Differences?

In the past, a coaxial cable was used to transmit audio and video. But then it was gradually replaced by HDMI and digital optical. It is known that the quality of audio can largely affect your experience. With the birth of HDMI ARC, you may struggle to choose HDMI ARC or digital optical. To better understand the differences between HDMI ARC и digital optical, you need to dive into our article.

Что такое HDMI ARC?

HDMI ARC means Audio Return Channel, first introduced in HDMI 1.4 standard. Before the introduction of HDMI 1.4, the HDMI port only allows for one-direction transmission from source equipment to displays. HDMI ARC allows for bi-directional transmission, so you never need an extra audio cable. Audio and video signals are transmitted from the source device to the display, then the audio signal will be transmitted by HDMI ARC back to the A/V receiver. For example, if you use the стандартный кабель HDMI, you need to use one HDMI cable to connect the sound bar and TV and another audio cable to transmit audio signals from the TV to the soundbar. HDMI ARC has totally changed this condition as it allows for video and audio transmission through a single HDMI cable.

HDMI ARC allows for high-quality audio transmission and supports various multi-channel audio formats like Dolby and DTS. However, the compatibility of certain audio formats with your soundbar may vary depending on the manufacturer.

HDMI ARC can also help you remote control the volume of your AV equipment through HDMI CEC (Consumer Electronics Control). Now there is eARC which stands for Enhanced Audio Return Channel. It is the next version of ARC, delivering better-quality audio and video.

Note: The eARC standard is introduced by the latest HDMI 2.1 with broader bandwidth and higher speed. It supports 24-bit/192kHz, uncompressed 5.1 and 7.1 data streams and 32-channel audio. Different from HDMI ARC, eARC can support Dolby® TrueHD and DTS-HD. Moreover, eARC has improved an automated lip-sync function so that you don’t need to make any adjustments yourself.

What is Digital Optical?

Digital optical is also known as TOSLINK cables, and they have been commonly used in audio and video devices since 1983. Digital optical is generally composed of optical fiber, transmitting audio signals using light. The optical cables are not easy to get ground loop and are resistant to exterior interference, widely used in home entertainment devices such as CD players and DVD players. Though they have been replaced by more modern cables like HDMI in some applications, digital optical is still used for older devices. Despite HDMI accounts for more of the market now, optical cables have their advantages. They transmit audio via the multichannel surround sound mode, which gives people a better experience.

Please note that digital optical is only capable of transmitting audio data. These cables can support uncompressed and compressed audio over long distances.

HDMI ARC and optical share the same purposes, for example, they both support multi-channel audio from one device to many other devices. But they also have some differences and we’ll further explore them in the following content.

Differences between HDMI ARC and Optical