Here is an example of a piano before voicing:

The piano after voicing

This was a well made piano from Yamaha, made under the Cable & Nelson brand. The piano was very abrasive sounding, and the owner agreed to voice it. They have since been happy with the results.

The art of voicing is task of manipulating the hammers to alter the felts density, and therefore either soften or harden the impact it has on the strings.

If you want to go beyond simply tuning, regulating and voicing are the next steps to take to improve your experience.