A piano roll is a music storage medium used to operate a player piano, piano player or reproducing piano. A piano roll is a continuous roll of paper with perforations (holes) punched into it. The perforations represent note control data. The roll moves over a reading system known as a 'tracker bar' and the playing cycle for each musical note is triggered when a perforation crosses the bar and is read.
The majority of piano rolls play on three distinct musical scales. The 65-note (with a playing range of A1 to C♯7) format was introduced in 1896 in the USA specifically for piano music. In 1900 an American format playing all 88 notes (A0 to C8) of the standard piano scale was introduced. In 1902 a German 72-note scale (F1, G1 to E7) was introduced. All of these scales were subject to being operated by piano rolls of varying dimensions. The 1908 Buffalo Convention of US manufacturers standardized the US industry to the 88-note scale and fixed the physical dimensions for that scale.
Piano rolls were in continuous mass production from around 1896 to 2008, and are still available today, with QRS Music claiming to have 45,000 titles available with "new titles being added on a regular basis". Largely replacing piano rolls, which are no longer mass-produced today, MIDI files represent a modern way in which musical performance data can be stored. MIDI files accomplish digitally and electronically what piano rolls do mechanically. Software for editing a performance stored as MIDI data often has a feature to show the music in a piano roll representation.
The Buffalo Convention of December 10, 1908 established two future roll formats for the US-producers of piano rolls for self-playing pianos. The two formats had different punchings of 65 and 88 notes, but the same width ( inches or 286 millimetres); thus 65-note rolls would be perforated at 6 holes to the inch, and 88-note rolls at 9 holes to the inch, leaving margins at both ends for future developments. This made it possible to play the piano rolls on any self-playing instrument built according to the convention, albeit sometimes with a loss of special functionality. This format became a loose world standard.
Metronomic or arranged rolls are rolls produced by positioning the music slots without real-time input. The music, when played back, is typically purely metronomical. Metronomically arranged music rolls are deliberately left metronomic so as to enable a player-pianist to create their own musical performance via the hand controls that are a feature of all player pianos.
Hand played rolls are created by capturing in real time the hand-played performance of one or more pianists upon a piano connected to a recording machine. The production roll reproduced the real-time performance of the original recording when played back at a constant speed. It is industry convention for recordings of music intended to be used for dancing to be regularized into strict tempo despite the original performance having the slight tempo fluctuations of all human performances.
Reproducing rolls are the same as hand-played rolls but have additional control codes to operate the dynamic modifying systems specific to whichever brand of reproducing piano it is designed to be played back on. The roll plays back at a fixed constant speed to preserve the inter-relationship of these control codes and the time it takes for the pianos dynamic mechanisms to operate between sequential control codes.
The player piano gives the opportunity to create music that is impossible for humans to play, or, more correctly, music that was not conceived in terms of performance by hand. Over one hundred composers wrote music specially for the player piano during the course of the 20th century. Many mainstream composers experimented with its possibilities, including Igor Stravinsky, Alfredo Casella, and Paul Hindemith; others, including Conlon Nancarrow, made it their primary milieu.
The Duo-Art, Ampico, and Welte-Mignon brands were known as "reproducing" piano rolls, as they could accurately reproduce the touch and dynamics of the artist as well as the notes struck, when played back on capable pianos.
Rolls for the reproducing piano were generally made from the recorded performances of famous musicians. Typically, a pianist would sit at a specially designed recording piano, and the pitch and duration of any notes played would be either marked or perforated on a blank roll, together with the duration of the sustaining and soft pedal.
Reproducing pianos can also re-create the dynamics of a pianist's performance by means of specially encoded control perforations placed towards the edges of a music roll. Different companies had different ways of notating dynamics, some technically advanced, some secret, and some dependent entirely on a recording producer's handwritten notes, but in all cases these dynamic hieroglyphics had to be skillfully converted into the specialized perforated codes needed by the different types of instrument.
Recorded rolls play at a specific, marked speed, where for example, 70 signifies 7 feet (2.1 m) of paper travel in one minute, at the start of the roll. On all pneumatic player pianos, the paper is pulled on to a take-up spool, and as more paper winds on, so the effective diameter of the spool increases, and with it the paper speed. Player piano engineers were well aware of this, as can be seen from many patents of the time, but since reproducing piano recordings were generally made with a similar take-up spool drive, the tempo of the recorded performance is faithfully reproduced, despite the gradually increasing paper speed.
The playing of many pianists and composers is preserved on reproducing piano roll. Gustav Mahler, Camille Saint-Saëns, Edvard Grieg, Teresa Carreño, Claude Debussy, Manuel de Falla, Scott Joplin, Sergei Rachmaninoff, Sergei Prokofiev, Alexander Scriabin, Jelly Roll Morton and George Gershwin are amongst the composers and pianists who have had their performances recorded in this way.
Duo-Art featured artists such as Ignace Jan Paderewski, George Gershwin, Maurice Ravel, Teresa Carreño, Percy Grainger, Leopold Godowsky and Ferruccio Busoni. The Ampico brand's featured artists included Sergei Rachmaninoff, Leo Ornstein, Mischa Levitzki, Winifred MacBride, and Marguerite Volavy. Welte-Mignon, the earliest reproducing system, recorded artists such as Gustav Mahler, Camille Saint-Saëns, Claude Debussy, Manuel de Falla, Alexander Scriabin, Enrique Granados, Eugen d'Albert, Josef Lhévinne, Raoul Pugno, and Carl Reinecke (who was the earliest-born pianist to record in any media format).
There were hundreds of companies worldwide producing rolls during the peak period of their popularity (1900–1927). Some other non-reproducing rolls makers of live performances are listed below together with their most memorable recording artistes.
White-Smith Music Publishing Company v. Apollo Company, 209 U.S. 1 (1908), was a decision by the Supreme Court of the United States which ruled that manufacturers of music rolls for player pianos did not have to pay royalties to the composers. The ruling was based on a holding that the piano rolls were not copies of the plaintiffs' copyrighted sheet music, but were instead parts of the machine that reproduced the music.
This case was subsequently eclipsed by Congress's intervention in the form of an amendment to the Copyright Act of 1909, protecting them and introducing a compulsory license for the manufacture and distribution of such "mechanical" embodiments of musical works.
In most modern digital audio workstation software, the term "piano roll" is used to refer to a graphical display of, and means of, editing MIDI note data; as well as entering the pitch, length and velocity of notes manually, instead of recording the output of a keyboard or other device for entering note data. Usually a means of manually editing other aspects of the MIDI data, such as pitch bend or modulation, is also present, although not strictly part of the piano roll itself.