Young Brunette Girl At The Old Piano

There are also non-standard variants. On some pianos (grands and verticals), the middle pedal can be a bass sustain pedal: that is, when it is depressed, the dampers lift off the strings only in the bass section. This pedal would be used only when a pianist needs to sustain a single bass note or chord over many measures, while playing the melody in the treble section. On the Stuart and Sons piano as well as the largest Fazioli piano, there is a fourth pedal to the left of the principal three. This fourth pedal works in the same way as the soft pedal of an upright piano, moving the hammers closer to the strings.
Unusual pedals
The rare transposing piano, of which Irving Berlin possessed an example, has a middle pedal that functions as a clutch that disengages the keyboard from the mechanism, enabling the keyboard to be moved to the left or right with a lever. The entire action of the piano is thus shifted to allow the pianist to play music written in one key so that it sounds in a different key.