Sample rate
Also called kHz · 48kHz · 44.1kHz
Sample rate is how many times per second audio is measured when it is recorded, given in kHz. Most microphones run at 44.1kHz or 48kHz, which is plenty for speech.
The microphone test shows the sample rate your browser negotiated with the device.
In practice
Sample rate is rarely the cause of a bad sounding microphone. 44.1kHz and 48kHz both capture everything a voice produces. Problems arise mostly when different apps or devices expect different rates and audio is converted between them, which can occasionally cause crackle or a robotic sound.
How to check
The microphone test shows the sample rate your browser negotiated with the device. If you hear crackling, set the microphone and your speakers to the same rate in your operating system’s sound settings and test again. A rate far below 44.1kHz usually means a Bluetooth headset in call mode.