Fig 4Dampers, sustain and sostenutoHold 1–6 or a key · P sustain · O sostenutoall dampers down
Dampers off their strings, and what holds themKeys, underlevers, wires and sostenuto tabsStrings: their motion drawn eight times largerA damper is a felt block resting on its strings; while it rests there no string can ring. A key lifts its own damper through the key's tail and an underlever: after about 4.8 mm of the 10 mm dip, the damper starts to rise, 5.0 mm in all. Let the key go and the damper drops back, stopping the string within a tenth of a second. The sustain pedal raises a tray under every underlever, so all dampers lift 8.0 mm together and everything you play keeps ringing. The middle pedal, sostenuto, turns a rod whose lip slides in under the tabs of the dampers that are up at that moment. Those dampers stay up and their notes ring on, while every key played afterwards damps as usual, because its tab is below the lip. A held damper rests 4 mm up, with its tab on the lip.