How to use a Unix PC as a Vocal Monitor
If you have a computer running on Linux or BSD, a microphone connected to it, and a desire not to spend $50 on a very small amplifier, you can use a one line shell script to listen to yourself sing instead.
Listening to yourself through a vocal monitor gives a better indication of the pitch and timbre of your voice than just listening to yourself, as the sound reaching your ears from your mouth is affected by resonating through your head, like listening to someone talk through a bone wall covered by a wet blanket. A monitor will therefore be a more accurate reproduction of what you sound like to everyone else than “directly” listening to your own voice.