A nice small freeware tool to display live microphone input levels (meaning audio gain and frequency - the starting point for audio quality control in a gain structure), plus a mic volume and mute switch, and a headset volume level switch
Try using an Amplifier with anEqualizer (built-in one) to boost the energy of some of the audio bands. Many are like guitar amplifiers (with a MIDI input for instruments), but look for softwares that have a Microphone input, like this one: