Tempo
In classical music, tempo is typically indicated with an instruction at the start of a piece (often using conventional Italian terms) and, if a specific metrical pace is desired, is usually measured in beats per minute (BPM).
In modern classical compositions, a "metronome mark" in beats per minute, indicating only measured speed and not any form of expression, may supplement or replace the normal tempo marking, while in modern genres like electronic dance music, tempo will typically simply be stated in BPM.
This measurement and indication of tempo became increasingly popular during the first half of the 19th century, after Johann Nepomuk Maelzel invented the metronome.
[5] In classical music, it is customary to describe the tempo of a piece by one or more words, most commonly in Italian, in addition to or instead of a metronome mark in beats per minute.
Italian is typically used because it was the language of most composers during the time these descriptions became commonplace in the Western musical lexicon.
[6] Some well-known Italian tempo indications include "Allegro" (English "Cheerful"), "Andante" ("Walking-pace") and "Presto" ("Quickly").
The beats per minute (bpm) values are very rough approximations for 44 time, and vary widely according to composers and works.
Originally it implied a tempo very slightly faster than Andante, whereas now it is often used to indicate one that is just a little slower than Allegro.
Robert Schumann followed afterwards with increasingly specific markings, and later composers like Hindemith and Mahler would further elaborate on combined tempo and mood instructions in German.
9 is marked Im Tempo eines gemächlichen Ländlers, etwas täppisch und sehr derb, indicating a slowish folk-dance-like movement, with some awkwardness and much vulgarity in the execution.
In jazz and popular music lead sheets and fake book charts, terms like 'fast', 'laid back', 'steady rock', 'medium', 'medium-up', 'ballad', 'brisk', 'brightly', 'up', 'slowly', and similar style indications may appear.
In some lead sheets and fake books, both tempo and genre are indicated, e.g., 'slow blues', 'fast swing', or 'medium Latin'.
His English contemporaries Flanders and Swann have similarly marked scores, with the music for their song "The Whale (Moby Dick)" shown as 'oceanlike and vast'.
[citation needed] It is also possible to indicate a more or less gradual change in tempo, for instance with an accelerando (speeding up) or ritardando (rit., slowing down) marking.
Several terms, e.g., assai, molto, poco, subito, control how large and how gradual a change should be (see common qualifiers).
Although they are Italian, composers tend to employ them even if they have written their initial tempo marking in another language.
From the viewpoint of Kolmogorov's complexity theory, this means such a representation of the data that minimizes the amount of memory.
As shown in the bottom row of the table, the rhythm without pitch requires fewer bytes if it is "perceived" as it is, without repetitions and tempo leaps.
On the contrary, its melodic version requires fewer bytes if the rhythm is "perceived" as being repeated at a double tempo.
Generally speaking, the more redundant the "musical support" of a rhythmic pattern, the better its recognizability under augmentations and diminutions, that is, its distortions are perceived as tempo variations rather than rhythmic changes: By taking into account melodic context, homogeneity of accompaniment, harmonic pulsation, and other cues, the range of admissible tempo deviations can be extended further, yet still not preventing musically normal perception.
[31] Such tempo deviations are strictly prohibited, for example, in Bulgarian or Turkish music based on so-called additive rhythms with complex duration ratios, which can also be explained by the principle of correlativity of perception.
[32]Twentieth-century classical music introduced a wide range of approaches to tempo, particularly thanks to the influence of modernism and later postmodernism.
[citation needed] While many composers have retained traditional tempo markings, sometimes requiring greater precision than in any preceding period, others have begun to question basic assumptions of the classical tradition like the idea of a consistent, unified, repeatable tempo.
Polytemporal compositions deliberately utilise performers playing at marginally different speeds.
