How to use
- Put your headphones on the right way round (look for L and R) or turn on your speakers at a moderate volume.
- Click the Left, Center or Right speaker, or Play left → center → right.
- With a pair of speakers, compare the in-phase test with the out-of-phase test.
Options explained
- Center
- Both sides equally loud, so the sound should come from straight ahead. If it leans to one side, check the balance setting in your sound settings.
- Phase test
- Both channels play the same 120 Hz hum. In phase it sounds full and centred; out of phase it sounds hollow and hard to place. If out of phase sounds fuller, one speaker’s wires are reversed.
What each button plays
Each speaker button plays three short beeps, one every 0.4 seconds, so the whole test lasts about 1.2 seconds. The pitch differs by side, which makes it easier to tell the tests apart when you are not looking at the screen:
| Button | Pitch | Channels |
|---|---|---|
| Left | 523 Hz (C5) | Left only |
| Center | 587 Hz (D5) | Left and right equally |
| Right | 659 Hz (E5) | Right only |
Play left → center → right runs the three in turn. If you hear the 523 Hz beep in your right ear, the channels are swapped. If the 587 Hz beep sounds stronger on one side, the balance setting or one driver is at fault. A quiet or missing beep on one side that follows the headphones from one device to another points to the headphones; one that stays with the device points to the device.
Frequently asked questions
Left plays on the right. What now?
Check you are wearing the headphones the right way round, then look for a "swap left/right channels" option in your system or player, or swapped speaker cables.
One side is silent.
Try another pair of headphones or another port. If both pairs fail on one side, the problem is the computer or phone; if only one pair does, it is the headphones. Re-pair Bluetooth earbuds.
Why can't I hear left and right on my phone speaker?
Many phones have one speaker, or two very close together. Use headphones or separated speakers for this test.
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