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At What Speed Should a Piano Roll be Played?

Author: David Back, May 2012.

Playing Piano Rolls

At what speed should a piano roll be played? The obvious answer is the "roll speed" which is often printed on the roll. This is generally somewhere between 50 and 120, the units are (feet per minute) X 10, i.e. between 5 and 12 feet per minute.

This is all very well when the roll is being played in a pianola which could be calibrated by making markings on the roll a known distance apart say 10 feet and measuring the time the roll takes to move from one mark to the other. In this case if the roll speed is 100 then the playing speed should be adjusted so that it takes 1 minute to cover this distance.

Piano Rolls as Midi Files

When the roll has been scanned and is presented as a midi file the roll speed can be safely ignored as a measurement of speed because the roll is no longer available and feet per minute means nothing to a midi file whose speed is judged by musical tempo in beats per minute.

What you should look out for is the roll tempo which, if it has been correctly calculated and inserted in the midi file, is the playing tempo to which the midi file should be set.

If the midi file does not contain accurate textual roll tempo information or if the playing tempo has been left at the midi default of 120 beats per minute then you are on your own with regard to playing tempo. You can put up with it as it is or use vanBasco's Karaoke Player which can be speed adjusted to whatever you think is right while the music is playing.

However a better way would be to find the musical score and check what the composer said. This is likely to be something like Andante, Allegro or Tempo di Marcia; but what do these mean?

Fortunately musicians have over the centuries agreed on a scale of speeds for these terms as indicated in the table.

Musical Speeds
Musical TermBeats per Minute
Larghissimo less than 20
Grave 20-40
Lento or Largo 40-60
Larghetto 60-66
Adagio 66-76
Adagietto 70-80
Andante Moderato A bit slower than Andante
Andante (Walking Pace) 76-108
Moderato 108-120
Allegretto Less than Allegro
Allegro Moderato 112-124
Allegro 120-168
Vivace (Lively and Fast) 140
Presto (Very Fast) 168-200
Prestissimo Greater than 200

Unfortunately the publishers of Scott Joplin's music used these terms only rarely in their published music but there are some clues:
Eugenia is annotated Slow March 72bpm
Sugar Cane and Pineapple Rag are annotated Slow March 100bpm
Bink's Waltz is annotated Andante 144bpm which you see from the table is a musical contradiction.

What is a Beat?

Musically a beat is the duration of a quarter note or a crotchet so beats per minute is equal to the number of crotchet notes per minute.

These beats may be typically made up from mixtures of crotchets, quavers (half as long as a crotchet) or semiquavers (quarter as long as a crotchet) or rests. For simplicity I have omitted notes of other durations.

Most piano rolls which have been converted to midi files use the midi default time signature of 4/4 which means four crotchets per bar, the midi default key of C which has no sharps or flats and often the midi default of 120 beats per minute. This nonconformity to normal musical practice does not affect the music when the file is played at the correct speed.

Conclusion

You will gather from the above information that the speed a midi file should be played (especially midified piano rolls) is not necessarily the speed which is encoded in the file but should be adjusted (You can use Cakewalk or any other midi editor) to the roll tempo if it is known or to be within the general ranges above according to the annotations in the printed music. This speed is not critical to the enjoyment of the music provided it is adjusted within reasonable limits.

Note 1. Do not edit the master roll files. Edit a copy and change the file name so it is obvious it is not a master roll file.

Note 2. Some piano rolls, in particular Maple Leaf Rag Uni-Record 202705 have been wrongly converted to midi. All the note durations are out by a factor of two. This means roll tempo and the bpm displayed by Cakewalk are also out by the same factor. This does not affect the music when the file is played at the right speed. Do not be fooled by this type of error.

Note 3. I have noted during this research that some of the midi files which I have computer processed for this web site could perhaps be slightly speed adjusted and then re-processed. I will be looking into this in due course but have already noticed that the music does not always sound "right" when played at the speed annotated by the publishers.