Bluetooth Audio Test

What is this tool?

The Bluetooth Audio Test plays audio to whatever output your system has selected. If that output is a paired Bluetooth device, you are testing the Bluetooth path — but the page is doing it the only way a browser can: by generating known signals and asking you what you hear.

It includes a six-step stereo sequence and separation audit, a playback stability test where you report dropouts, a pulse-stutter check, frequency band checks for bass (40–250 Hz) and treble (4–18 kHz), a ten-round blind speaker identification game, an A/B comparison between system audio and Bluetooth audio, and an interactive delay check. The guided paths are an eight-step quick test and a fourteen-phase full test.

The signal chain is pure Web Audio: an oscillator through a gain node and a stereo panner, split into independent left and right analysers for two digital dBFS meters, then merged back to the destination. Pan runs from 100% left to 100% right and gain is ramped over 0.015 s at each change so nothing pops.

How to use it

1. Pair and select the device in your operating system firstThis page cannot pair anything. Connect the headphones or speaker in your OS Bluetooth settings and make sure it is the selected output device, then come back and reload if you switched outputs mid-session.
2. Confirm sound, then check stereoStart playback and run the six-step stereo sequence. Left, right and centre should be unambiguous. Many Bluetooth speakers are physically mono even when they accept a stereo stream, so a centred image on both sides is expected on those.
3. Run the stability test and report dropoutsThe stability test plays continuously while you mark any interruption you hear. Nothing is detected automatically — your reports are the data. Walking away from the source during this test is the fastest way to find a range limit.
4. Run the pulse-stutter checkRegular pulses make small gaps far easier to notice than continuous tone does, because a missing pulse breaks an obvious rhythm.
5. Check the bass and treble bandsThe bass check covers 40–250 Hz and the treble check 4–18 kHz. These are the two regions where a lossy Bluetooth codec and a speaker's own DSP make the biggest difference, so they are where a wired comparison is most informative.
6. Try the delay check and the A/B comparisonThe delay check flashes the screen and plays a synchronised beep, and you respond — so the number includes your own reaction time. The A/B comparison lets you switch between system audio and the Bluetooth device to hear the difference directly rather than from memory.

What the results mean

The two dBFS meters

The left and right meters come from independent analyser nodes reading the signal this page generated, before it ever reaches the Bluetooth radio. They confirm that stereo content is being produced and panned correctly; they are not a measurement of what your headphones emitted.

Dropouts you reported

Each dropout you mark is a real audible interruption, and the pattern matters more than the count. Dropouts that increase with distance point at range or interference; dropouts that happen at a fixed spot point at a physical obstruction; dropouts that only start after several minutes often point at a power-saving or connection-stability problem.

The delay figure

Read this as “flash to my response”, not as “codec latency”. It bundles the Bluetooth link delay together with your visual reaction time, which for most people is 200–300 ms on its own. It is useful for comparing two devices under the same conditions and useless as an absolute latency number. The page states this under its own latency FAQ.

Bass and treble outcomes

Missing bass usually reflects driver size; a dull or absent top end more often reflects the codec or the speaker's tuning. Comparing the same band wired against Bluetooth is what separates the two, and the A/B control exists for exactly that.

Stereo separation and identification

If the identification game is easy, separation is good. If it is guesswork, the device is either mono, downmixing, or applying a spatial effect that blurs the image.

What it can detect

• A Bluetooth device that is connected for media but producing no sound
• Audible dropouts and stutters, with the pattern you observed while they happened
• A mono device, a downmixed stream, or swapped channels
• Weak bass or a dull top end, comparable directly against wired output
• A perceptible audio delay relative to on-screen events, measured with your reaction included

Limits worth knowing

A browser can only report what the platform gives it. These are the honest boundaries of this page, so a result is never read as more than it is.

• This page never touches the Web Bluetooth API. There is no navigator.bluetooth call and no device request anywhere in its engine — it simply plays audio to whatever output your operating system has selected. Every Bluetooth-specific conclusion comes from what you hear, which is what the page's “WHY BROWSER CANNOT PROBE BLUETOOTH INTERNALS” section explains.
• It cannot report the codec in use. SBC, AAC, aptX and LDAC negotiation happens between your operating system and the device, below anything a web page can observe. The page's “Can this tool detect Bluetooth codecs?” FAQ answers this directly.
• It cannot report signal strength, packet loss, link quality, battery level, firmware version or device model. Those live in the Bluetooth stack, not in the browser, and the page's own FAQs say so for each of them.
• The delay figure is not a latency measurement of the Bluetooth link. It is a visual-flash reaction test, so it includes your reaction time; treat it as a relative comparison only.
• A dropout heard here cannot be attributed to a cause by the page. Interference from 2.4 GHz Wi-Fi, distance, obstructions, USB 3 radio noise and the host's own power management all produce the same audible symptom.

Tips

• Test wired first with the same tools, then Bluetooth. Any difference between the two runs belongs to the wireless path; anything present in both belongs to the device or your ears.
• For the stability test, walk your normal route — to the kitchen, around a wall, behind a monitor. Dropouts that only happen where you actually sit or walk are the ones worth solving.
• If the audio delay bothers you in video, check whether your device supports a low-latency mode and whether your player has an audio-offset setting; the delay itself is a property of the link, not of this page.

Troubleshooting

Related documentation

• AudioHeadphone TestEars, balance, separation, bass and treble checks built for headphones and earbuds.
• AudioSpeaker TestLeft, right, stereo, bass, treble and sweep tones for laptop or desktop speakers.
• AudioAudio Bass Test20 Hz to 250 Hz tones for sub-bass reach, rattle hunting and distortion checks.
• AudioStereo TestChannel isolation, balance, separation and phase checks for any stereo setup.
• AudioMic Latency TestObserved acoustic loopback latency over ten rounds, with jitter and P95.