Testbench

Speaker test — play left, centre or right

Channel—
Frequency—Hz
Channel test
Tone generator
440 Hz
30%

Rear panel

SPK Speaker test

Measures
Left / right / center channels, tone generator, sweep
Browser API
Web Audio StereoPannerNode · AudioContext.setSinkId
Known quirks
Picking an output device works in Chrome and Edge only. Bluetooth headsets drop to low quality while a mic is open.

Operating procedure

Press Left, Center or Right. The sound should come only from that side. Then try the sweep to hear how low and high your speakers go.

  1. Turn your system volume down to about a third, then press Left. The sound should come only from the left speaker or earcup.
  2. Press Right, then Center. Center should sound equally loud on both sides, as if it came from the middle.
  3. Press Sweep to glide from 20 Hz to 20 kHz. Listen for rattles and buzzing, and note where the sound becomes audible and where it disappears.
  4. Use the Tone generator to hold one frequency, for example to find a resonance or to compare two speakers.
  5. On Chrome and Edge, pick the device in Output to test a second pair of speakers or headphones without changing system settings.

Fault codes

  1. SPK-E1

    Left and right are swapped

    Fix Check the plugs on the back of the speakers or the L/R marks on the headphones. On Windows, open Sound settings › your device › Properties and turn off any "swap channels" option in the driver's audio app. Bluetooth headsets sometimes swap channels after a firmware update.

  2. SPK-E2

    Sound comes from both sides on Left

    Fix Mono audio is turned on. On Windows: Settings › Accessibility › Audio › Mono audio. On macOS: System Settings › Accessibility › Audio › Play stereo audio as mono. On iPhone/Android, look under Accessibility › Audio.

  3. SPK-E3

    No sound at all

    Fix Check that the tab isn't muted (right-click the tab), the system output is the device you expect, and the volume isn't at zero. Some browsers block audio until you click on the page; pressing a button here counts.

  4. SPK-E4

    Low frequencies are missing

    Fix Small laptop and phone speakers usually can't play below 100–150 Hz. That's normal. With a subwoofer, check its crossover and that it's switched on.

  5. SPK-E5

    Crackling or buzzing

    Fix Crackling at all volumes often comes from a loose cable or a Bluetooth connection with interference. Buzzing on low tones is usually something rattling: a loose grille, screws or an object resting on the speaker.

Service notes

How do I test left and right speakers?
Press Left and listen: the sound must come only from the left speaker or earcup. Then press Right. If the sides are swapped or both play, check cables, mono-audio settings and the L/R marks.
What frequency range can people hear?
Roughly 20 Hz to 20,000 Hz for young ears. The top limit drops with age; many adults stop hearing somewhere between 14 and 17 kHz. That's why the sweep may go silent before the end.
Is this speaker test safe for my speakers?
Yes at reasonable volume. Start low. Loud, high tones and long low-frequency tones at full volume can damage small speakers and tweeters, and your ears.
Can I choose which speakers to test?
In Chrome and Edge on desktop, yes: use the Output list. Other browsers always use the system default output, so change it in your operating system's sound settings.
Does it work with Bluetooth headphones?
Yes. Expect a short delay between pressing a button and hearing the sound; that's normal Bluetooth latency.