Speaker test: left/right, phase and bass
This speaker test checks speakers, headphones and your computer or car audio in four parts: left and right (a voice names the side and the beeps come only from that side), phase (normal and inverted, to catch swapped wires), a sweep from 20 Hz to 20 kHz with buttons to mark where you started and stopped hearing it, and bass and subwoofer from 20 to 120 Hz.
How to use it
- Turn your device volume down, set the page Volume to 30% and raise it gradually.
- Tap Left, Center and Right (or Sequence): the beeps must come from the highlighted side; on Center, from both sides equally.
- In Phase, play Normal and then Inverted: Normal should sound more solid in the middle and have more bass.
- During the sweep, tap Started hearing when the sound appears and Stopped hearing when it fades out.
- For the subwoofer, play the 20 to 120 Hz tones or the bass sweep and mark where the bass kicks in.
Help and explanations
Your browser generates the sound on the spot: nothing to download, no sign-up. For an exact frequency or another waveform, use the tone generator.
Left, right and phase
If the Left beep comes out of your right ear, the headphones are on backwards or the channels are swapped in the cable, the adapter or your settings. If it sounds the same on both sides, your device is set to mono audio (under Accessibility on iPhone and Android) or the speaker is mono. The voice plays on both channels because the browser can't pan speech; the beeps show the side.
The phase test plays the same hiss (pink noise) on both sides, first identical and then with one side inverted. Wired correctly, Normal sits in the middle with bass; Inverted sounds spread out, “outside your head”, and thinner. If Inverted sounds better on your speakers, one speaker has its + and − wires swapped. On a single speaker (a phone, a mono mini speaker) Inverted almost disappears because the two sides cancel out: that's expected.
Sweep: how low and how high you can hear
The sweep climbs from 20 Hz to 20 kHz, spending the same time on each octave. What you mark is the whole chain: your ears, the headphones or speaker, and the noise in the room. With the same ears, swapping headphones shows which pair goes lower and higher; with the same headphones, it hints at your high-frequency limit, which drops with age. It isn't a hearing test.
Bass and subwoofer test
Play 40, 60 and 80 Hz at the same volume: if one disappears or booms, it's usually the room or the sub's crossover. The bass sweep goes from 20 to 120 Hz in 20 seconds; mark where the bass appears and listen for rattling panels, doors or loose screws, which buzz at a single frequency. For Bluetooth speakers (JBL and others), the spec sheet lists the lowest bass: around 40 Hz for the big ones, over 100 Hz for pocket-sized ones.
Tips
- To compare two pairs of headphones or two speakers, use the same volume and the same spot.
- On a PC, first check that the right output is selected in the Windows or macOS sound icon.
- For car audio, set balance and fader to the center before the left/right test.
- Bluetooth adds a little delay: wait for the beeps before deciding a side is dead. Esc stops everything instantly.
Frequently asked questions
How do I check if my headphones play on both sides?
Tap Left and Right. If one side is silent, wiggle the plug and nearby cable while it plays: if the sound cuts in and out, it's the cable or the jack. With Bluetooth earbuds, put both back in the case and pair them again. There's also the left right headphone test, with a tone that switches sides by itself.
How do I run a bass test on my speaker?
With the volume low, play 60 Hz and raise it to a comfortable level. Then run the bass sweep and mark where the sound starts. If something buzzes at just one frequency, it's a loose part vibrating, not a faulty speaker.
How do I know if my speakers are out of phase?
In the phase test, Normal should sound centered and have more bass than Inverted. If it's the other way round, turn the amp off, swap the two wires on one side only and repeat.
Why can't I hear the bass on my phone?
Phone and laptop speakers are too small to play below about 150 to 200 Hz. The 20 to 120 Hz tones only show up on headphones, bigger speakers or a subwoofer.
Can the sweep be used as a hearing test?
No. It marks how far you can hear with those headphones, at that volume and in that place, which is useful for comparing gear. To check your hearing, see an audiologist or ENT doctor.
Can a speaker test damage my speakers or headphones?
Not at normal volume. A steady tone puts all its energy into a single frequency: very loud bass pushes the cone too far and loud treble heats up the tweeter. Turn it up gradually and back off at the first crackle.
Does it work on a PC, a laptop and a car stereo?
It works in any current browser. In the car, connect your phone by cable or Bluetooth; the phase test reveals a door speaker wired backwards.