If you‘ve shopped for soundbars or glanced at your TV‘s ports, you‘ve likely seen HDMI ARC and optical audio connections. But what do these actually do? What can each transmit? This guide examines the key distinctions in plain terms, so you can determine which works best for your needs.
First, let‘s define these two cable types on a basic level:
HDMI ARC – Stands for High Definition Multimedia Interface Audio Return Channel. It‘s an enhanced version of HDMI that allows 2-way audio transmission between your TV and an external speaker system.
Optical Audio – Also called TOSLINK or SPDIF. Uses fiber optic cables to send digital audio signals as pulses of light in one direction. Common in older home theaters.
Now, on to the nerdy differences…
Audio Format Support and Quality
If you want the very best sound quality from modern movie and music formats, HDMI ARC is the winner. Why? Because it supports higher bandwidth and advanced compression codecs that optical connections lack.
| Audio Format | HDMI ARC | Optical |
|---|---|---|
| Stereo | ✅ | ✅ |
| Dolby Digital 5.1 | ✅ | ✅ |
| DTS 5.1 | ✅ | ✅ |
| Dolby TrueHD | ✅ | ❌ |
| DTS-HD Master | ✅ | ❌ |
| Dolby Atmos | ✅ | ❌ |
| DTS:X | ✅ | ❌ |
As you can see in the table, optical is limited to basic 5.1 surround sound in Dolby and DTS formats. These are compressed to fit within optical‘s lower 384 kbps bandwidth ceiling.
HDMI ARC supports uncompressed, immersive Dolby Atmos and DTS:X sound thanks to far higher bandwidth capacity. This allows precise placement of audio objects in 3D space. Perfect for movies or gaming!
According to audio experts at Dolby, HDMI ARC also minimizes audio degradation issues that optical connections can suffer from. So advantage, HDMI.
Video Signals? Only HDMI Can Play
Here‘s a monumental difference many shoppers overlook: optical connections can only transmit audio! HDMI carries both digital video and audio.
So if you want to route 4K HDR video from your media streamer or gaming console through your soundbar to the TV, HDMI ARC is mandatory. Optical audio connections simply cannot pass through any video signal information. Keep this in mind!
Cable Length and Interference Resistance
When it comes to cable runs, optical audio has a key advantage. The fiber optic material is inherently resistant to electromagnetic interference (EMI). This allows reliable audio transmission at lengths over 50 feet without degradation.
Copper HDMI cables succumb to interference more easily. Picture dropout and audio hiccups become likely beyond 30-40 feet, especially at high Ultra HD bandwidths. Long HDMI runs may need active repeaters.
So if you have a long cable run between media rack and TV, optical‘s resilience can prove useful. Locate gear closer together though, and HDMI is less problematic.
Automatic Control Convenience
This is a cool bonus feature of HDMI ARC. It supports advanced Consumer Electronics Control (CEC) integration between connected devices. This means your TV remote can also control volume, mute and power on your soundbar automatically. No extra soundbar remote needed!
With optical audio connections, no such control integration exists. You‘ll be juggling multiple remotes, and likely needing to manually sync audio delay as well. HDMI ARC really simplifies an advanced home theater system into one neat package.
Real-World Usage Recommendations
For streaming music to a simple bluetooth speaker or soundbar, optical should work reasonably well. But add 4K video or Dolby Atmos to the mix, and HDMI ARC ultimately outpaces optical audio.
Here are some usage guidelines:
- Watching movies with Dolby Atmos sound → Choose HDMI ARC
- Gaming in 4K HDR → HDMI ARC Required
- Basic music listening → Optical OK
- Connecting TV beyond 30 ft → Consider Optical
The added functionality of HDMI ARC does come at a small price premium over basic optical cables. But for robust home theaters, improved audio and total control integration make HDMI ARC easily worth the spend.
Hopefully this clear guide helps explain what distinguishes these two audio options. Simply put, HDMI ARC is the way of the future thanks to more advanced format support and connectivity conveniences. Make sure your next AV gear investment is HDMI ARC enabled!
