The HT-X8500 is a single-bar 2.1 soundbar that fakes height with Sony's Vertical Surround Engine — so "Atmos working" means it's receiving a Dolby Atmos signal and virtualizing it, not driving real up-firing drivers. When it won't engage, the break is almost always upstream: the TV's digital output set to PCM, or the source not sending Atmos at all. Confirm what the bar is getting before you change anything.
The two ways to feed it
The HT-X8500 has an HDMI input and an HDMI eARC output, so there are two paths:
- TV apps → bar: the TV passes Atmos back over (e)ARC to the bar's HDMI OUT. eARC is best (it carries the full Atmos); plain ARC carries lossy Atmos via Dolby Digital Plus.
- Source → bar → TV: plug an Apple TV/player into the bar's HDMI IN, and the bar passes video through to the TV on its HDMI OUT. This route hands Atmos straight to the bar and sidesteps the TV's audio settings.
Fix it
- Set the TV's digital audio output to Pass-Through / Bitstream / Auto — not PCM. PCM strips the Atmos metadata, and it's the single most common cause of "no Atmos." (On a Sony Bravia: Settings > Display & Sound > Audio output > Digital audio out > Auto — the full TV-side path is in Sony Bravia eARC not passing Atmos.)
- Use the eARC port and a certified Ultra High Speed cable. If you're going TV-to-bar over ARC, you'll only get lossy Atmos at best; eARC carries the full signal. Make sure the cable is in the TV's eARC-labeled port.
- Turn Atmos on at the source. The streaming app or player must be set to output Dolby Atmos / Dolby Digital Plus, and the content has to be an Atmos title. It's often off by default.
- Check what the bar is actually receiving. Press the AUDIO / Display button on the HT-X8500 remote — the front display shows the incoming format ("Dolby Atmos," "Dolby Audio," "PCM"). If it reads PCM, the TV is decoding instead of passing — go back to step 1.
- Power-cycle in order. Unplug the TV and bar for at least 30 seconds, power the TV first, then the bar, to re-run the handshake.
The simplest fix when the TV fights you
If your TV's passthrough settings are a maze, route the source through the bar instead: Apple TV / player → HT-X8500 HDMI IN → HDMI OUT → TV. Now the bar receives Atmos directly and the TV only handles video, so the TV's audio menu stops mattering. (Remember the Apple TV's Atmos needs eARC if you go the other way, TV-to-bar — this input route avoids that entirely.)
FAQ
The bar's display says PCM, not Atmos — why? The TV is decoding to PCM instead of passing the bitstream. Set the TV's digital audio output to Pass-Through/Bitstream and it switches to Dolby.
Does the HT-X8500 have real height speakers? No — it's a 2.1 bar that virtualizes height with Vertical Surround Engine. It still needs a true Atmos signal to do it. For bars with real up-firing drivers, see the best Dolby Atmos soundbars.
ARC or eARC for Atmos? eARC carries the full Atmos; plain ARC only the lossy Dolby Digital Plus version. Use the TV's eARC port with a certified cable — ARC vs eARC and the cables you need breaks down the difference.
Atmos won't pass from my Apple TV. Going TV-to-bar, the Apple TV's Atmos needs eARC. Easier: plug the Apple TV into the bar's HDMI IN so it feeds the bar directly.