Regulation and Voicing of the piano centers around the “action” of the piano. People are amazed at just how complex the inner workings of the piano are. There are over 25 different points of adjustment for each note to play. And they all have to be in proper adjustment to work properly. If your keys are sticking, or it feels uneven, you hear a clicking sound, then you may need to have your action regulated.
Voicing is the sound of your piano, it is when the “hammer” strikes the string. Over time a hammer will develop “grooves and cuts” from striking the strings. They also may become hard. This will cause a piano to sound bright, brash, not sweet. There are many different techniques in “voicing the hammer”. Sometimes they will help and sometimes they will need to be replaced.