Темп в музыке: скорость и обозначения

Musical concept indicating to the speed of interpretation

In musical terminology, tempo (Italian for 'time'; plural 'tempos', or tempi from the Italian plural), also known as beats per minute, is the speed or pace of a given composition. In classical music, tempo is typically indicated with an instruction at the start of a piece (often using conventional Italian terms) and is usually measured in beats per minute (BPM). In modern classical compositions, a "metronome mark" in beats per minute may supplement or replace the normal tempo marking, while in modern genres like electronic dance music, tempo will typically simply be stated in BPM. Tempo may be separated from articulation and meter, or these aspects may be indicated along with tempo, all contributing to the overall texture. While the ability to hold a steady tempo is a vital skill for a musical performer, tempo is changeable. Depending on the genre of a piece of music and the performers' interpretation, a piece may be played with slight tempo rubato or drastic variances. In ensembles, the tempo is often indicated by a conductor or by one of the instrumentalists, for instance the drummer.

Although tempo is described or indicated in many different ways, including with a range of words (e. g., "Slowly", "Adagio", and so on), it is typically measured in beats per minute (bpm or BPM). For example, a tempo of 60 beats per minute signifies one beat per second, while a tempo of 120 beats per minute is twice as rapid, signifying two beats every second. The note value of a beat will typically be that indicated by the denominator of the time signature. For instance, in time, the beat will be a crotchet, or quarter note. This measurement and indication of tempo became increasingly popular during the first half of the 19th century, after Johann Nepomuk Maelzel invented the metronome. Beethoven was one of the first composers to use the metronome; in the 1810s he published metronomic indications for the eight symphonies he had composed up to that time. With the advent of modern electronics, beats per minute became an extremely precise measure. Music sequencers use the bpm system to denote tempo. In popular music genres such as electronic dance music, accurate knowledge of a tune's bpm is important to DJs for the purposes of beatmatching. The speed of a piece of music can also be gauged according to measures per minute (mpm) or bars per minute (bpm), the number of measures of the piece performed in one minute. This measure is commonly used in ballroom dance music.

In different musical contexts, different instrumental musicians, singers, conductors, bandleaders, music directors or other individuals will select the tempo of a song or piece. In a popular music or traditional music group or band, the bandleader or drummer may select the tempo. In popular and traditional music, whoever is setting the tempo often counts out one or two bars in tempo. In some songs or pieces in which a singer or solo instrumentalist begins the work with a solo introduction (prior to the start of the full group), the tempo they set will provide the tempo for the group. In an orchestra or concert band, the conductor normally sets the tempo. In a marching band, the drum major may set the tempo. In a sound recording, in some cases a record producer may set the tempo for a song (although this would be less likely with an experienced bandleader). Differences in tempo and its interpretation can differ between cultures, as shown by Curt Sachs when comparing Tunisian with Western Classical melodies, while certain genres display rhythmic variation in line with its forms, as occurs with flamenco and its palos.

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. Some well known Italian tempo indications include "Allegro" (English "Cheerful"), "Andante" ("Walking pace") and "Presto" ("Quickly"). This practice developed during the 17th and 18th centuries, the baroque and classical periods. In the earlier Renaissance music, performers understood most music to flow at a tempo defined by the tactus (roughly the rate of the human heartbeat). The mensural time signature indicated which note value corresponded to the tactus. In the Baroque period, pieces would typically be given an indication, which might be a tempo marking (e. g. Allegro), or the name of a dance (e. g. Allemande or Sarabande), the latter being an indication both of tempo and of metre. Any musician of the time was expected to know how to interpret these markings based on custom and experience. In some cases, however, these markings were simply omitted. For example, the first movement of Bach's Brandenburg Concerto No. 3 has no tempo or mood indication whatsoever. Despite the increasing number of explicit tempo markings, musicians still observe conventions, expecting a minuet to be at a fairly stately tempo, slower than a Viennese waltz; a perpetuum mobile quite fast, and so on. Genres imply tempos, and thus, Ludwig van Beethoven wrote "In tempo d'un Menuetto" over the first movement of his Piano Sonata Op. 54, though that movement is not a minuet. Many tempo markings also indicate mood and expression. For example, presto and allegro both indicate a speedy execution (presto being faster), but allegro also connotes joy (from its original meaning in Italian). Presto, on the other hand, simply indicates speed. Additional Italian words also indicate tempo and mood. For example, the "agitato" in the Allegro agitato of the last movement of George Gershwin's piano concerto in F has both a tempo indication (undoubtedly faster than a usual Allegro) and a mood indication ("agitated"). Often, composers (or music publishers) name movements of compositions after their tempo (or mood) marking. For instance, the second movement of Samuel Barber's first String Quartet is an Adagio.

English indications, for example 'quickly', have also been used, by Benjamin Britten and Percy Grainger, among many others. 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'. The genre indications help rhythm section instrumentalists use the correct style. For example, if a song says 'medium shuffle', the drummer plays a shuffle drum pattern; if it says 'fast boogie woogie', the piano player plays a boogie woogie bassline. 'Show tempo', a term used since the early days of vaudeville, describes the traditionally brisk tempo (usually 160–170 bpm) of opening songs in stage revues and musicals. Humourist Tom Lehrer uses facetious English tempo markings in his anthology Too Many Songs by Tom Lehrer. For example, "National Brotherhood Week" is to be played 'fraternally'; "We Will All Go Together" is marked 'eschatologically'; and 'Masochism Tango' has the tempo 'painstakingly'. 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'.

Tempo is not necessarily fixed. Within a piece (or within a movement of a longer work), a composer may indicate a complete change of tempo, often by using a double bar and introducing a new tempo indication, often with a new time signature and/or key signature. 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. Indeed, some compositions chiefly comprise accelerando passages, for instance Monti's Csárdás, or the Russian Civil War song Echelon Song. On the smaller scale, tempo rubato refers to changes in tempo within a musical phrase, often described as some notes 'borrowing' time from others.

Twentieth century classical music introduced a wide range of approaches to tempo, particularly thanks to the influence of modernism and later postmodernism. 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. Graphic scores show tempo and rhythm in a variety of ways. Polytemporal compositions deliberately utilise performers playing at marginally different speeds. John Cage's compositions approach tempo in diverse ways. For instance 4′33″ has a defined duration, but no actual notes, while As Slow as Possible has defined proportions but no defined duration, with one performance intended to last 639 years.

In popular music genres such as disco, house music and electronic dance music, beatmatching is a technique that DJs use that involves speeding up or slowing down a record (or CDJ player, a speed adjustable CD player for DJ use) to match the tempo of a previous or subsequent track, so both can be seamlessly mixed. Having beatmatched two songs, the DJ can either seamlessly crossfade from one song to another, or play both tracks simultaneously, creating a layered effect. DJs often beatmatch the underlying tempos of recordings, rather than their strict bpm value suggested by the kick drum, particularly when dealing with high tempo tracks. A 240 bpm track, for example, matches the beat of a 120 bpm track without slowing down or speeding up, because both have an underlying tempo of 120 quarter notes per minute. Thus, some soul music (around 75–90 bpm) mixes well with a drum and bass beat (from 150 to 185 bpm). When speeding up or slowing down a record on a turntable, the pitch and tempo of a track are linked: spinning a disc 10% faster makes both pitch and tempo 10% higher. Software processing to change the pitch without changing the tempo is called pitch shifting. The opposite operation, changing the tempo without changing the pitch, is called time stretching.