Microphone hum near a charger: what to check

Your microphone sounds clear until you plug in a charger, then a low buzz or steady hum appears in recordings or calls. The noise may be coming from the charger itself, or it may be electrical interference entering through the microphone, cable, or computer.

Compare recordings with the charger connected and disconnected using the Microphone Test. The test shows whether the noise reaches the microphone, but it cannot identify the exact electrical cause on its own.

Test the microphone near the charger

1. Open the Microphone Test and press Start microphone. Allow microphone access when your browser asks.
2. Choose the microphone you normally use. Keep the microphone, its cable, and your position still while you speak a short phrase or sit quietly for a few seconds.
3. Check the signal meter and waveform. Press Record 5 seconds, then play the recording back and listen for a steady hum or buzz.
4. Repeat the same short recording with the charger unplugged from the wall. Keep the microphone and computer in the same positions, and use the same microphone each time.
5. If the noise changes, repeat the comparison once more. You can also select another microphone from the list to see whether the noise follows one device or appears on several.

For a fair comparison, avoid changing several things at once. If the microphone is built into a laptop, unplugging its charger may also change the computer's power mode, so note that difference. Do not touch exposed wiring or use a damaged charger during the test.

What the result means

The hum stops when you unplug the charger

The charger or the powered setup is involved, but that does not prove the charger is defective. The microphone may be picking up an audible buzz from the charger, or electrical noise may be entering through the computer, USB connection, or audio cable. Try the fixes below to narrow it down.

The hum stays about the same

The charger is less likely to be the main cause. Check the microphone's input level, cable, and nearby sources of sound such as a fan or lamp. If the hum is present in only one calling or recording app, check that app's selected microphone and audio settings.

The noise changes when you move the microphone

The microphone may be hearing a sound made by the charger, or its cable may be picking up interference. A small charger can produce a faint buzz or high-pitched whine that is hard to hear in the room but clear in a recording. Move the charger farther away and route its power cable away from the microphone cable to see whether the recording improves.

The meter moves, but the noise is hard to hear

A moving meter only shows that the microphone is receiving sound. It does not mean the sound is a problem. Listen to the recording at a comfortable volume, and compare the same quiet section with and without the charger connected.

How to reduce charger-related hum

1. Move the charger away from the microphone. Put the charger and its power cable farther from the microphone and audio cable. Avoid coiling the microphone cable around the charger cable.
2. Try battery power briefly. If it is safe and practical, unplug the computer's charger and repeat the test. If the hum disappears, reconnect the charger and try a different wall outlet. Do not use an outlet that is loose, damaged, or sparking.
3. Check the input level. A very high input level can make quiet background noise more noticeable. On Windows 11, open Settings › System › Sound, select your microphone under Input, and lower its input volume a little. On macOS, open System Settings › Sound › Input and adjust the input volume. Retest after each change.
4. Reconnect the microphone. For a USB microphone, try another USB port and connect it directly to the computer instead of through a hub. For an analog microphone, check that the plug is fully seated and the cable is not sharply bent.
5. Compare with another microphone or charger. If possible, test the microphone on another computer, or use a compatible, reputable charger with the correct specifications. Change one item at a time so you can tell which change affects the hum.
6. Close other audio apps and retest. A calling app may apply noise processing or select a different input. Close other recording and calling apps, then check the chosen microphone in the app where you noticed the problem.

Is it sound from the charger or electrical interference?

If you can hear the buzz near the charger without recording, the microphone may simply be capturing a real sound in the room. Some chargers make a faint mechanical whine or buzz, which can become more noticeable when the microphone is close. Moving the charger away is the simplest check.

If the recording contains a low hum that is difficult to hear directly, the noise may be entering through an electrical connection. This can happen with some combinations of charger, computer, microphone, and connected audio equipment. Mains-related hum often has energy around 50 or 60 Hz, depending on the region, and may include higher harmonics. A browser recording cannot confirm the source or diagnose a grounding fault, so treat this as a clue rather than a verdict.

Do not remove a ground pin, open a charger, or use an adapter intended to defeat electrical safety grounding. If a charger is unusually hot, damaged, buzzing loudly, or smells burnt, stop using it and replace it with a suitable charger or contact the device maker.

When the microphone or charger may be faulty

If the hum follows the microphone to another computer, even with the charger far away, inspect the microphone and cable. If it appears only with one charger, test that charger with another compatible device if the maker's guidance allows it. A damaged cable, microphone, or charger may need replacement. For a device under warranty, contact the manufacturer before opening it or attempting a repair.

The Microphone Test processes the check in your browser, and recordings stay on your device.