Why Is My Sonos Arc Not Producing Surround Sound?

Problem Description

Your Sonos Arc soundbar is failing to produce surround sound or Dolby Atmos effects, resulting in a less immersive audio experience. This can be due to TV settings, content limitations, or incorrect Sonos setup.

Why This Happens in Real Homes

The Arc can decode Dolby Atmos and Dolby Digital 5.1, but only when the audio is delivered correctly over eARC. If you are on a standard ARC connection, the bandwidth caps at about 1 Mbps, which means you get compressed Dolby Digital at best — no Atmos, no TrueHD. Even on eARC, the TV has to be set to Passthrough or Bitstream so it sends the untouched surround stream instead of downmixing to stereo PCM internally. Streaming apps are another gotcha — Netflix sends Atmos but only on its Premium plan, and the TV's native app must support it. Check the Sonos app under System > About My System to see what audio format the Arc is actually receiving in real time.

Symptoms

• Audio sounds like stereo, not surround
• No overhead or side effects
• Sonos app shows "Stereo PCM" instead of Dolby Atmos
• Specific movies/shows lack surround sound
• Happens after TV settings change
• Other Sonos features work fine

Recognize these? Here's what usually causes it.

Common Causes

• TV audio output settings (PCM vs Bitstream)
• Content is not surround sound compatible
• Incorrect HDMI ARC/eARC connection
• Outdated TV or Sonos firmware
• Trueplay tuning issues
• External device audio settings

Tools & Requirements

Step-by-Step Solution

1

Adjust TV Audio Output Settings

Access your TV"s audio settings menu. Make sure the audio output format is set to "Bitstream", "Dolby Digital", "Dolby Digital Plus", or "Passthrough" instead of "PCM" or "Stereo". For Dolby Atmos, make sure your TV"s HDMI eARC port is enabled and set to "Passthrough" or "Auto".

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2

Verify Content is Surround Sound Compatible

Not all movies, TV shows, or streaming services offer surround sound or Dolby Atmos. Make sure the content you are playing explicitly states it supports these formats. Check the audio settings within the streaming app or Blu-ray player.

3

Check HDMI ARC/eARC Connection

Make sure your Sonos Arc is connected to your TV"s dedicated HDMI ARC (Audio Return Channel) or eARC port. This port is usually labeled and is essential for transmitting high-quality audio formats like Dolby Atmos. Disconnect and reconnect the HDMI cable firmly.

4

Update TV and Sonos Firmware

Make sure both your TV and your Sonos Arc have the latest firmware. Outdated firmware on either device can cause compatibility issues with surround sound formats. Check your TV"s settings for software updates and your Sonos app (Settings > System > System Updates) for Arc firmware.

5

Re-run Trueplay Tuning

After verifying all connections and settings, re-run Trueplay tuning in the Sonos app (Settings > System > Trueplay). Trueplay calibrates the Arc to your room"s acoustics, optimizing the soundstage and surround effects for your specific environment.

Quick Solutions

Still having issues? This is usually the deeper cause below.

Need More Help? Sonos Support

Note: The contact information below connects you directly to Sonos's official customer support team, not Trunetto. They can help with warranty claims, device replacements, and advanced technical issues.