These hammers are covered with felt so they don’t damage the strings. The strings of the piano are stretched across a metal frame. The frame is made up of iron or steel, and it is bolted to the wooden soundboard of the piano.
When the hammers strike the strings, they cause the entire soundboard to vibrate. The soundboard is a large, thin piece of wood that is made of spruce or another resonant wood. The vibration of the soundboard amplifies the sound from the strings.
The soundboard also has a number of holes in it, which helps to project the sound. The sound from the soundboard travels through these holes and into the air, where it can be heard by listeners.
The strings are mounted over a sounding board which acts like a big amplifier, magnifying the sound produced by the vibrating strings. The pitch (how high or low a note sounds) of each note is determined by the length and thickness of the string. In general, the longer the string, the lower the pitch; and the thinner the string, the higher the pitch.
Additionally, the action of pressing a key does not only cause a hammer to strike a string. It also causes a damper (a small felt or rubber pad) to be lifted off of the string. Dampers are crucial components in stopping notes after they are played. When the key is released, the damper stops the vibration of the string and the note is no longer heard.
There are pedals at the bottom of the instrument which can be pressed by the player’s feet to change the instrument’s sound and sustain notes when desired.