Thomas Loud (1802) introduced diagonal stringing in upright pianos. By varying the proportions and adjustment of parts, piano makers have been able to produce differences in tone, power and touch. Certain essential parts are common to all pianos. Besides the case there is the 'frame,' which sustains the tension of the strings; the 'sounding-board,'; which is the voice of the instrument; and the 'action,' which is the mechanism that sets the strings in vibration.
Music for the piano is written on the bass and treble staves, and like
the organ, the piano is tuned to the system of equally tempered intervals.
Equal Temperament is the mode of tuning now applied to all fixed-tone instruments.
In it, the octave is divided into twelve steps, each note being the same
ratio to the one immediately above and below it. In 1936, a piano keyboard
with a 17 note octave was introduced by A.C. Ogolenet, a Moscow musician.
His inspiration came from the fact that the present keyboard did not differentiate
between sharps and flats. The first method of playing an ordinary piano
by mechanical means seems to have been invented by Debain of Paris about