Every grand and upright piano requires dampers to stop the vibrations of the string after the key is pressed and released. Dampers prevent the vibration of the string from continuing to resonate once the key is released.
We have replaced the felt on these Steinway dampers and are preparing to install them back into the piano and regulate them to concert specifications. Regulating dampers is part of the rebuilding process.
This is a set of dampers in a new Baldwin grand.
In the video below you can see the dampers in the piano moving and working properly.