Digital Coaxial Cable for TV: Surround Sound from Your TV
A digital coaxial cable for TV is the simplest way to move surround sound from a TV with a coaxial (orange) digital output to a soundbar, receiver or speaker system – one cable, no power, no configuration beyond a menu or two. Yet the connection still produces a steady stream of no-sound and mono-only support questions. This guide covers which TV port to use, the cable spec that matters, the exact settings on both devices, why some TVs still ship coax in the HDMI era, and the troubleshooting order that resolves the common failures.
Quick Answer
Plug a 75 ohm S/PDIF digital coax cable (orange RCA plugs) from the TV’s ‘Digital Out Coaxial’ port to the soundbar’s or receiver’s ‘Digital In Coaxial’ port, then select that input on the receiving device. In the TV’s audio menu, choose bitstream for 5.1 decoding on the soundbar, or PCM for stereo. The cable carries PCM up to 24-bit/192 kHz and compressed 5.1 at 48 kHz – no power is needed, the signal is one-way, and no video travels on the line.
Finding the Coaxial Port on Your TV
On the back panel, look for the orange RCA socket labeled ‘Digital Out Coaxial’, ‘Coaxial Out’ or ‘S/PDIF Out’, usually paired with a clear optical socket under a ‘Digital Audio Out’ group. Not every TV has one: the newest slim panels are dropping the coax out in favor of HDMI eARC and optical only, so check the panel before buying the cable. A related warning: the TV’s ‘audio return’ direction matters – the coax out sends the TV’s audio out, and it cannot receive the soundbar’s return signal; that return path is HDMI eARC’s job. For the port-level spec, see our digital audio out coaxial guide.
TVs that dropped coax: the HDMI-only era
Current-generation panels increasingly expose only optical and HDMI audio. If your TV lacks the coax out, the options are the optical output (same S/PDIF ceiling, different plug), HDMI eARC from a compatible bar, or an active optical-to-coax converter where the soundbar truly needs coax. The cable you already own does not change the port the TV has.
The Right Cable: 75 Ohm S/PDIF Build
The cable is a digital coax cable: 75 ohm coaxial with RCA plugs, orange by convention. Length is the main decision – measure the actual route with a serviceable drape and add 30 cm; a TV-to-wall-mount-bar run is commonly 2 to 5 meters. Build quality matters at the long end: foil plus braid shield, oxygen-free copper, clean crimps. A thin budget cable that works on the bench can crackle once it is dressed along a cable tray, because the shield is what rejects the TV’s own switching noise. The spec checklist is in our digital RCA cable guide, and the input-side pairing in coaxial digital inputs.
TV Plus Soundbar/Receiver Settings
Two menus decide whether the chain delivers surround. On the TV: set the digital audio output format to bitstream for 5.1 content (the soundbar decodes) or PCM for stereo; set the sample rate to 48 kHz if the bar is picky; and confirm the TV is not routing audio to its built-in speakers simultaneously if you want the bar to own the sound. On the soundbar or receiver: select the coaxial/digital coax input, enable the decoder, and set the surround mode to auto or the matching format. A quick verification: play a 5.1 test track and confirm the receiving device displays ‘Dolby Digital 5.1’ or ‘DTS’.
Troubleshooting TV Coaxial Audio
No sound: confirm the input selection on the bar, confirm the cable is in the coax out (not the headphone jack or the optical neighbor), and confirm the TV’s audio output is not disabled. Sound but mono: the TV is sending PCM because the content has no 5.1 track, or the bar’s decoder is disabled – check the source track first. Crackle under load: a marginal cable or loose plug – reseat, then swap in a known-good 75 ohm cable. Nothing at 96/192 kHz: the bar likely caps at 48 kHz; lock the TV rate lower. When in doubt, the optical input on the same bar is the control experiment – if optical works and coax does not, the coax cable or plug is the fault.
TV Digital Output Options Compared
| Port | Audio ceiling | Surround | Notes |
|---|---|---|---|
| Coaxial out (S/PDIF) | 24/192 PCM | 5.1 at 48 kHz | One-way, no video, most robust |
| Optical out (TOSLINK) | 24/192 PCM | 5.1 at 48 kHz | Ground-isolated, fragile fiber |
| HDMI ARC / eARC | Per spec version | 7.1 and HD codecs | Two-way, needs compatible bar |
| 3.5 mm headphone | Analog stereo | Stereo only | Fallback, low quality at distance |
Real-World Applications
The TV coax path is the default in specific rooms: a living room where the TV’s digital out feeds a wall-mounted soundbar and HDMI is reserved for the streaming stick; a bedroom TV paired with a compact bar where the coax run hides in the wall chase; a rental or hospitality property where the cheap, durable coax standardizes every room; a gaming setup where the console’s audio rides the TV’s coax out to the receiver; a kitchen TV feeding a single under-cabinet speaker amp; and a commercial display wall where the panel’s coax out drives a small PA zone. In each case the value proposition is identical: one unpowered cable, a spec that has not changed in decades, and a connection that outlives both devices at the ends of it.
Related Guides
Frequently Asked Questions
Can a digital coaxial cable carry both TV audio and video?
No – audio only. S/PDIF carries one audio stream. Video needs HDMI, optical is audio-only too, and the old RF antenna path is a separate technology.
Why does my TV’s coax out sound worse than optical?
It should not – the ceilings are identical. A perceived difference almost always means the coax cable or plug is marginal: longer run, thinner shield, or a loose crimp. Swap in a known-good 75 ohm cable before changing anything else.
Do I need to change TV settings after plugging in the cable?
Yes: select the coax input on the receiving device, and set the TV’s digital output format (bitstream or PCM) and sample rate to match. Most ‘no surround’ complaints are this menu pair, not the cable.
Will this work with smart TV streaming apps?
Usually, yes – most apps expose their audio to the TV’s digital out. Some apps or codecs output PCM-only or cap the rate; if 5.1 is missing, check whether the content itself is encoded 5.1 before blaming the chain.