Draft ARC/eARC story

Author: jlian

content/posts/arc-downgrade.md

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+---
+title: "When “downgrading” to ARC fixes everything"
+date: 2025-11-20T09:00:00-08:00
+draft: true
+tags: [home theater, hdmi, arc, samsung, denon]
+featured_image: "/images/posts/arc-downgrade/featured-new.png"
+description: "Backing away from Samsung eARC on the S95B made the audio stack calm down."
+---
+
+In the [HDMI-CEC post](/posts/hdmi-cec/) I mentioned that my Samsung TV is on **ARC (not eARC)**. This is the backstory: eARC wouldn’t stay put, so the “downgrade” was the only way to make the stack boring again.
+
+## Setup
+
+The living-room rack looks like this:
+
+- Samsung **S95B** on its eARC HDMI port
+- **Denon AVR-X1700H** acting as the switch for every input
+- CEC left on everywhere, no exotic cabling
+
+With **HDMI eARC Mode = Auto**, the S95B would:
+
+- Boot to **TV Speakers** instead of “Receiver (HDMI-eARC)”
+- Quietly flip back to TV Speakers after app changes
+- After the 1651 firmware update, *always* wake up in TV Speakers even with an ARC/eARC device attached ([Samsung Community][1])
+
+This was before the Raspberry Pi CEC automation from the other post, so the goal was simply to stop burning energy on eARC.
+
+## The nudge
+
+While doomscrolling for answers I ran into a Sonos Community thread titled something like **“Samsung S95C and Sonos Arc – issues with eARC”**. Different hardware, same failure mode: random dropouts, TV defaulting to its own speakers, general unreliability. The replies that reported success all did the same thing—force the Samsung back to ARC and leave everything else alone. ([Sonos Community][2]) Good enough for an experiment.
+
+## The actual change
+
+On the **Samsung S95B**:
+
+- `Settings → Sound → Expert Settings → HDMI eARC Mode` → **Off**
+- Leave **Anynet+ (HDMI-CEC)** on
+- `Sound Output` now lists **Receiver (HDMI)** without the eARC badge—select that
+
+On the **Denon X1700H**:
+
+- **HDMI Control = On**
+- **ARC = On**
+
+Then power-cycle the Denon, power-cycle the TV, and let them renegotiate.
+
+After that sequence the TV consistently booted to **Receiver (HDMI)** and stopped randomly switching back mid-app-hop. Still not perfect, but the issue fell from “daily” to “rare enough to ignore.”
+
+## What changed (and what didn’t)
+
+ARC can’t send Dolby TrueHD / DTS-HD MA / multichannel LPCM from TV apps to the receiver. It still carries Dolby Digital / Dolby Digital Plus 5.1 and DD+ Atmos, which is already the ceiling for Samsung’s streaming apps. ([AVForums][3]) Anything lossless that I care about (Apple TV, consoles) plugs into the Denon directly, so the audio-path downgrade cost nothing.
+
+## Why this matters for the CEC post
+
+Only *after* the ARC switch did I start the Raspberry Pi + `cec-client` automation described elsewhere. That work attacks a different pile of bugs: consoles waking the TV without waking the receiver, inputs drifting, etc. Trying to automate around that while the TV kept defecting to TV Speakers would have been unhinged.
+
+So if your setup looks similar—a Samsung S95-series panel, eARC-capable AVR or soundbar, recurring “why is it on TV Speakers again?” moments—the lowest-effort move is still the one I stole from Sonos: disable **HDMI eARC Mode**, let the TV fall back to ARC, and see if the system calms down before layering in automation.
+
+[1]: https://eu.community.samsung.com/t5/tv/s95b-update-1651-defaults-the-output-to-tv-speakers-at-startup/td-p/11349869?utm_source=chatgpt.com "S95B Update 1651 defaults the output to TV Speakers at startup"
+[2]: https://en.community.sonos.com/home-theater-228993/samsung-s95c-and-sonos-arc-issues-with-earc-6888562?utm_source=chatgpt.com "Samsung S95C and Sonos Arc – issues with eARC"
+[3]: https://www.avforums.com/threads/samsung-tv-s95b-and-soundbar-q990b-settings.2420641/?utm_source=chatgpt.com "Samsung TV S95B and Soundbar Q990B Settings"