There are many factors to what makes your piano sound like it does. The age of the string, the bridge, and the hardness of the hammers to name a few. The hardness or softness of a hammer can make a piano sound bright and harsh or mellow and muted. Through various methods a piano can be voiced to your preference of brightness. If your 20 or 30 year old Yamaha Grand hurts your ears and sounds like you're playing in a tin can voice it!
Depending on the use of your piano, some regulation may be needed to properly voice the Hammers. Your piano also needs to be in tune to voice the hammers correctly. You will be surprised to hear the difference voicing can make and how it can change the enjoyment you get out of clean your piano.
Voicing starts at 175