<P> The soft pedal, or una corda pedal, was invented by Bartolomeo Cristofori . It was the first mechanism invented to modify the piano's sound . This function is typically operated by the left pedal on modern pianos . Neither of its common names--soft pedal or una corda pedal--completely describe the pedal's function . The una corda primarily modifies the timbre, not just the volume of the piano . </P> <P> Soon after its invention, virtually all makers integrated the una corda as a standard fixture . On Cristofori's pianos, the una corda mechanism was operated by a hand stop, not a pedal . The stop was a knob on the side of the keyboard . When the una corda was activated, the entire action shifted to the right so that the hammers hit one string (una corda) instead of two strings (due corde). </P> <P> Dominic Gill says that when the hammers strike only one string, the piano "...produces a softer, more ethereal tone ." </P> <P> By the late 18th century, piano builders had begun triple stringing the notes on the piano . This change, affecting the una corda's function, is described by Joseph Banowetz: </P>

What does the 3 pedals on a piano do