Razer Blade 15 microphone isn't working or doesn't pick up any sound. Don't worry its a simple fix, follow the steps below. The Razer Blade 15 comes with a Realtek Microphone installed near the camera in the bezel. The issue arises from the Realtek software that comes pre-installed on the Razer Blade 15.
Head to Realtek Audio Console and open the microphone section
Turning off Microphone Effects 'All Off' fixed the issue. The microphone started working correctly again.