Decibic

Local Web Audio diagnostic

Surround sound test

Send a short tone to one browser channel at a time, then compare what you hear with the browser-reported route. Channel labels describe conventional stream roles, not proven physical speakers.

Local only · no upload
Start with your system, receiver, and speakers turned down.

This tool starts at 8% internal gain, but a browser cannot limit amplification after your device. Remove headphones if you are checking room speakers, and stop if a cue is uncomfortable.

1. Prepare and enable

Audio begins only after your confirmation and button press.

8%

This caps only the generated signal. It does not read or change system, receiver, or amplifier volume.

Confirm the low-volume check to enable audio.
Web Audio
Not started
Reported maximum
Not checked
Active route
None
Sample rate
Not checked

2. Choose a route and cue

Only layouts at or below the current destination's browser-reported maximum are offered.

No route has been opened. The browser may expose only mono or stereo even when an operating system or receiver supports more channels.

Current cue No cue
Idle

Manual channel cues

One short tone per press

Enable audio to reveal channels reported for the current destination.

How to use

  1. Lower every volume control. Confirm the safety check, then enable audio with a deliberate press.
  2. Read the browser report. Choose only a route the tool offers; a higher operating-system setting does not make hidden browser channels addressable.
  3. Compare cues cautiously. Use the sequence for order, or press one channel repeatedly. The on-screen name is the intended stream role.
  4. Stop when finished. Stop audio closes the AudioContext. Hiding the page or moving focus away also stops it as a safety measure.

What this result means

  • Hearing a cue confirms that some audible path rendered that indexed browser channel. It does not identify the physical speaker, cable, amplifier input, or operating-system mapping.
  • Silence can come from browser limits, downmixing, disabled speakers, routing, bass management, or hardware. This page cannot isolate which layer caused it.
  • Headphones, spatial-audio features, and virtual surround may fold or reposition channels. Headphone direction is not proof of a discrete loudspeaker route.
  • This test does not validate codec passthrough, Dolby or DTS decoding, Atmos objects, timing alignment, level calibration, polarity, or acoustic phase.