What is a sustain pedal

The right pedal, also called the sustain pedal, also called the resonance pedal. It was invented by the Englishman John Broadwood in 1783. It is usually the rightmost inner pedal under the piano. It is also called "amplifier" in the book. When the sustain pedal is pressed, it is usually pressed on the strings. The damper (Damper) on it immediately raised. Make all the strings continue to vibrate, and after the pedal is released, all the dampers are all pressed on the strings to stop the sound. Since pressing the damper pedal will expand the sound to a certain extent, it is also called the Loud Pedal.