Mic volume changes when another app starts a call

Your voice sounds fine until another app starts a call, then it gets quieter, louder, or starts cutting out. The cause may be automatic gain control in the calling app, a microphone setting, or the operating system handing the microphone to a different app.

Compare the microphone before, during, and after the call. The Microphone Test shows the input level and waveform, so you can check whether the signal itself changes or whether only the call sounds different.

Check whether the microphone input changes

Open the Microphone Test, choose the microphone you use for calls, and press Start microphone. Allow microphone access when your browser asks.
Speak a short sentence from your usual position. Note how far the signal meter moves and what the waveform looks like. Keep your voice and distance similar for each comparison.
Start the other app's call without closing the test. Say the same sentence again and watch the signal meter. If the browser test loses access, note the message and continue to the next step.
End the call and repeat the sentence once more. Check whether the meter returns to its earlier level.
Try Auto volume in the test both on and off. This helps show whether automatic level adjustment changes the result. Do not change your speaking distance between tries.

The meter is useful for comparing the same setup, not for measuring your voice in a studio. Room noise, speaking distance, and the microphone's direction can all change the reading.

What the result means

The test level changes when the call starts

The signal reaching the browser really is changing, or access to the microphone is being affected. The call app may be adjusting input gain, switching to another microphone, or applying noise processing. Check the selected input and automatic gain settings in the call app.

The test level stays the same, but people hear you differently

The microphone itself is probably producing a steady signal. The call app may be changing its own input level, noise suppression, or echo cancellation, or the people on the call may have different playback levels. Check the app's microphone preview and input selection rather than raising the system input volume immediately.

The test stops or reports that another app is using the microphone

The other app may have exclusive access, or the browser and app cannot use the microphone at the same time in that setup. Close the call app and test again. If the microphone works once the app is closed, focus on its audio settings and permissions rather than assuming the microphone is broken.

The level changes even after the call ends

An app or device setting may have changed the input level and left it there. Check the system input volume, then restart the app and compare again. For more on automatic gain, see how to check if microphone automatic gain is too aggressive.

How to stop the volume changing

Choose the same microphone in both apps. In the call app's audio settings, select the headset or built-in microphone you tested. Do not leave it on an automatic device choice if the app keeps switching inputs.
Check automatic input adjustment. Look in the call app's audio or microphone settings for automatic gain, automatically adjust microphone volume, or similar wording. Turn the adjustment off for a test, then speak at a steady distance. App labels vary, so do not change unrelated noise controls at the same time.
Set a sensible system input level. In Windows 11, open Settings › System › Sound, select your microphone under Input, and check its input volume. On a Mac, open System Settings › Sound › Input, select the microphone, and check its input level if that control is available.
Allow microphone access. In Windows 11, open Settings › Privacy & security › Microphone and enable microphone access and desktop app access. On a Mac, open System Settings › Privacy & Security › Microphone and allow access for the browser and call app.
Check Windows communications behavior. Windows can lower the volume of other sounds when it detects a call. This normally changes playback, not the microphone input. To change it, open Control Panel, choose Hardware and Sound › Sound › Communications, and select Do nothing if you do not want Windows to lower other sounds.
Check app permissions on a phone. On Android, open Settings › Apps › [call app] › Permissions › Microphone. On iPhone, open Settings › Privacy & Security › Microphone and allow the app. Mobile apps may adjust the microphone internally, with fewer controls than desktop apps provide.
Reconnect the microphone and restart the apps. Unplug and reconnect a wired headset, or disconnect and reconnect a Bluetooth headset. Then close and reopen the browser and call app so each can detect the same input device.

When the microphone may be faulty

Test the microphone with the call app closed, then try it on another computer or phone if possible. If the level still jumps, crackles, or drops when you move the cable, the headset, cable, port, or built-in microphone may be failing. A replacement headset is a useful comparison. If the built-in microphone fails across multiple apps and after a restart, contact the device maker or a repair shop.

Why a call can change what you hear

Microphone input and speaker playback are separate signals. A call app can raise or lower your microphone level before sending your voice, while Windows may lower music or other playback when a call begins. Noise suppression can also reduce a quiet voice if it mistakes it for background noise. Compare the browser test meter with the call app's own microphone preview to see which part of the path is changing.

The Microphone Test runs in your browser. Any short recording you make there stays on your device.