Some time ago I noted the availability of installable audio metering for Windows. Today I stumbled upon a similar free application called “VUMeter” that provides old school stereo VU meters.
The meters can be resized from 50%, 100% or 200% of normal size, where normal size is 1500 x 300 pixels.
They can be set to stay on top of all windows. They can also be set to display the signal from any available sound recording or playback device.