Mini-Spectra
Mini-Spectra is a small and lightweight spectrum analyzer for Windows. It stays on right side of the taskbar without affecting your productivity and it will make your desktop much more attractive than before!
You can change the color of the spectrum to match your current theme. Also you can adjust the opacity if needed. Mini-Spectra can capture audio samples in real-time from any(render/capture) audio device of your PC. You can set it to capture audio samples from PC speaker or microphone.
(Since the installer made with NSIS, some AVs may report false positives)