How to test left and right speakers, step by step
To test stereo, play sound that is clearly separated: a tone or voice in the left channel, then in the right. If only one side plays, the cause is usually a balance setting, a mono accessibility option, a loose plug or a Bluetooth earbud that is not connected. Start at a low volume before you run any test, because some test tones are loud and a sudden loud sound can hurt your hearing.
Speaker testIs sound coming from both sides?OpenRun a left-right test
Use the speaker test to play tones in each channel. Headphones separate the channels most clearly, so start with them if you have a pair. Sound should come from one side, then the other. If both channels seem to come from the same spot, the output may be mono. If one side is silent, work through the causes below in order. If the sides seem reversed, with left sounds coming from the right, the cable, adapter or headset may have its channels swapped, so try a different cable or device to confirm.
Set the system volume to about a quarter before you start, then raise it gradually. Never begin at full volume with headphones on.
Balance and mono settings
A balance setting can push all the sound to one side, which sounds exactly like a dead speaker. On macOS, the balance slider is in the sound output settings. On Windows, the balance control sits in the properties of the output device, reached from the sound settings. Centre it, then test again.
Mono audio
Operating systems include an accessibility option that plays stereo sound as mono, so both sides carry the same audio. It helps some people with hearing differences in one ear. If it is on, a stereo test will sound like one channel, centred. Look for the audio options under Accessibility in your system settings, and turn the mono option off unless you need it.
Inspect the jack and cable
A 3.5 mm headphone plug has separate rings, and each ring carries a channel. If the plug is not pushed fully in, one ring may not connect, so one side is cut or crackles. Push the plug in firmly, then gently move the cable while a sound plays. If the crackle changes with the movement, the jack or cable is worn. Try another port or another cable before you assume the speaker is faulty.
Bluetooth earbuds and speakers
With true wireless earbuds, the two buds link to each other and to your device. If one is out of battery, out of the case, or not fully paired, you can hear sound from one side only, or mono sound. Put both buds back in their case, charge them, and reconnect. Some Bluetooth speakers play in stereo only when two units are paired as a stereo pair, so check the speaker's manual or app if you expect stereo from a single unit.
Using a sweep to find rattles
A frequency sweep plays tones that slowly move from low to high pitch. Its job is to reveal rattles, buzzes and distortion that a single steady tone can hide. A loose panel, a grille or a damaged cone often rattles only at particular pitches. Listen for a sound that appears at one point in the sweep and stops once the sweep passes it. Note the pitch if you can, then check that part of the case or enclosure.
Keep the volume low while you listen, and raise it only if you can hear the sweep clearly.
What a sweep cannot tell you
Your own hearing sets limits:
- Healthy young ears typically hear from about 20 Hz to 20 kHz. The top of that range fades with age, so you may hear nothing above some point even while the speaker is still producing sound. That says nothing about the speaker, so ask someone with better hearing to check the highest tones.
- Small laptop and phone speakers reproduce low bass poorly. A quiet bottom end is normal for them, and not a fault.
| What you hear | Probable cause | Next step |
|---|---|---|
| Only the left or only the right | Balance, mono option, or jack | Balance, then mono option, then the plug |
| Crackle when the plug moves | Worn jack or cable | Try another port or cable |
| Rattle at one pitch | Loose part or cone | Note the pitch, then check the case |
| Both sides, but thin | Mono option or wrong output device | Check the output device and the mono option |
If the problem is on the microphone side of a call instead, the microphone checklist walks through that.
Quick answers
Why does only one earbud play?
Often that bud is out of battery or not connected, or a mono setting is on. Charge both, reconnect, and check the mono option.
Should I test speakers at full volume?
No. Start low and raise the volume gradually, because some test tones are loud.
Is it a fault if I cannot hear the highest tones?
Not by itself. Hearing at the top of the range fades with age, so have someone with better hearing check.
