translate English to German: Some upright pianos have a practice pedal or celeste pedal in place of the sostenuto. This pedal, which can usually be locked in place by depressing it and pushing it to one side, drops a strip of felt between the hammers and the strings so that all the notes are greatly muted — a handy feature for those who wish to practice in domestic surroundings without disturbing the neighbours.
Zusätzlich stammt von Christofori die Doppelsaite, bei der jeder Ton durch zwei gleich gestimmte Saiten erzeugt wird.