Mono Test
Is your audio mono or stereo? Two quick sounds tell you. A chime sent only to the left channel is heard on both sides when the output is mono, and a special out-of-phase noise almost disappears in mono. Answer one question after each sound and the page tells you what you have, then how to switch.
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Step 1: one-sided sound
Step 2: cancellation check
Put on headphones if you have them, then press Left only.
How to check for mono audio
- Put on headphones or earphones if you have them; they make the answer obvious. On speakers, sit in the middle.
- Press Left only and answer where you heard it. On a stereo output it is only in your left ear; on a mono output it is in both.
- Press Normal noise, then Out-of-phase noise, and compare. In stereo both are about as loud; in mono the out-of-phase noise nearly vanishes.
- Read the result in the status line, then use the steps below to turn Mono Audio on or off.
What the results mean
The two steps check the same thing in different ways, so together they leave little doubt:
| Left only | Out-of-phase noise | Your output is |
|---|---|---|
| Left ear only | About as loud as normal | Stereo |
| Both ears | Nearly silent | Mono (Mono Audio on, or a mono device) |
| Both ears | About as loud | Mono by a different route, such as a single-speaker device that mixes in hardware |
| Right ear only | About as loud | Stereo with the channels swapped |
The out-of-phase noise is the same sound in both channels with one copy turned upside down. When a device mixes the two channels into one, the copies cancel, which is why it disappears in mono. For a full speaker check after switching, use the stereo test.
How to turn Mono Audio on or off
iPhone and iPad: Settings > Accessibility > Audio & Visual > Mono Audio. Android: Settings > Accessibility > Audio adjustment (or Hearing enhancements on Samsung) > Mono audio. Windows 11: Settings > Accessibility > Audio > Mono audio. Windows 10: Settings > Ease of Access > Audio > Turn on mono audio. Mac: System Settings > Accessibility > Audio > Play stereo audio as mono. Chromebook: Settings > Accessibility > Audio and captions > Play the same audio through all speakers.
When mono audio helps
Mono sends everything to both ears. It is the right choice if you hear better in one ear, wear a single earbud, or share a pair of earphones, because in stereo some instruments or a speaker in a video may be only in the ear you are not using. It is also safer for some podcasts and calls recorded with a voice on one side. For music, games and films, stereo gives you direction and space, so turn mono off unless you need it.
Common problems and fixes
Mono Audio is off but the test still says mono
The device itself may be mono: a single Bluetooth speaker, a phone in portrait, or a headset in hands-free (call) mode. On Bluetooth headphones, pick the "stereo" or "A2DP" device, not "Hands-Free".
I hear nothing on one side
That is a dead channel, not mono. Check the balance setting, the plug and the headphones with the headphone test.
The out-of-phase noise sounds odd on speakers
On speakers some cancellation happens in the room, especially in bass, so it can sound thin even in stereo. Headphones give the clearest result.
Frequently asked questions
How do I know if my audio is mono or stereo?
What is mono audio?
Is mono or stereo better?
Why does my phone play in mono?
Does a mono test work on speakers?
Do AirPods or Bluetooth earbuds play mono?
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