If your computer is running a Mac OS, check to make sure your headsets are compatible with Apple products. Macs use a different type of microphone input technology compared to other operating systems. This means that, even if you are using a headset with a built-in microphone, your Mac may not detect it and instead use the computer’s internal microphone.
An easy way to check if your headset is Mac-compatible is to plug it in and go to System Preferences → Sound → Input tab. If your computer is picking up the microphone from your headset, it should read “External Microphone”: