Information about Tempo

TEMPO
Other names	2,2,6,6-Tetramethyl-piperidin-1-oxyl
Identifiers
CAS number	2564-83-2
RTECS number	TN8991900
Properties
Molecular formula	C9H18NO
Molar mass	156.25 g/mol
Melting point	36-38 °C
Boiling point	sublimes under vacuum
Hazards
R-phrases	R34
S-phrases	S26 S36/37/39 S45
Except where noted otherwise, data are given for materials in their standard state (at 25 C, 100 kPa)

2,2,6,6-Tetramethylpiperidine-1-oxyl or TEMPO is the chemical compound with the formula (CH₂)₃(CMe₂)₂NO. This heterocycle is a red-orange, sublimable solid. As a stable radical, it has applications throughout chemistry and biochemistry.^[1] TEMPO was discovered by Lebelev and Kazarnowskii in 1960.^[2] It is prepared by oxidation of 2,2,6,6-tetramethylpiperidine. TEMPO is widely used as a radical trap, as a structural probe for biological systems in conjunction with electron spin resonance spectroscopy, as a reagent in organic synthesis, and as an initiator in polymer chemistry.^[3] The stability of this radical is attributed to the steric protection provided by the four methyl groups adjacent to the nitroxyl group.^[4]

Application in organic synthesis

TEMPO is employed in organic synthesis as a catalyst for the oxidation of primary alcohols to aldehydes. The actual oxidant is the N-oxoammonium salt. In a catalytic cycle with sodium hypochlorite as the stoichiometric oxidant, hypochlorous acid generates the N-oxoammonium salt from the TEMPO.

One typical reaction example is the oxidation of (S)-(-)-2-methyl-1-butanol to (S)-(+)-2-methylbutanal.^[5] 4-Methoxyphenethyl alcohol is oxidized to the corresponding carboxylic acid in a system of catalytic TEMPO and sodium hypochlorite and a stoichiometric amount of sodium chlorite.^[6] TEMPO oxidations also exhibit chemoselectivity, being inert towards a secondary alcohols, but the reagent will convert aldehydes to carboxylic acids.

In cases where secondary oxidizing agents cause side reactions, it is possible to stoichiometrically convert TEMPO to the oxoammonium salt in a separate step. For example in the oxidation of geraniol to geranial 4-acetamido-TEMPO is first oxidized to the oxoammonium tetrafluoroborate.^[7]

References

External links

• DataSheet

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In musical terminology, tempo (Italian for "time", from Latin Tempus) is the speed or pace of a given piece. It is an extremely crucial element of sound, as it can affect the mood and difficulty of a piece.

The plural of tempo in Italian is tempi. Some writers employ this plural when writing in English. Others use the native English plural tempos. Standard dictionaries reflect both usages.

Measuring tempo

The tempo of a piece will typically be written at the start of a piece of music, and in modern music is usually indicated in beats per minute (BPM). This means that a particular note value (for example, a quarter note or crotchet) is specified as the beat, and the marking indicates that a certain number of these beats must be played per minute. The greater the tempo, the larger the number of beats that must be played in a minute is and, therefore, the faster a piece must be played.

Mathematical tempo markings of this kind became increasingly popular during the first half of the 19th century, after the metronome had been invented by Johann Nepomuk Mälzel, although early metronomes were somewhat inconsistent. Some people consider Beethoven's metronome markings, in particular, to be notoriously unreliable.

With the advent of modern electronics, BPM became an extremely precise measure. MIDI files and other types of sequencing software use the BPM system to denote tempo.

As an alternative to metronome markings, some 20th century composers (such as Béla Bartók and John Cage) would give the total execution time of a piece, from which the proper tempo can be roughly derived.

Tempo is as crucial in contemporary music as it is in classical. In electronic dance music, accurate knowledge of a tune's BPM is important to DJs for the purposes of beatmatching.

Musical vocabulary for tempo

Whether a music piece has a mathematical time indication or not, in classical music it is customary to describe the tempo of a piece by one or more words. Most of these words are Italian, a result of the fact that many of the most important composers of the 17th century were Italian, and this period was when tempo indications were used extensively for the first time.

Before the metronome, words were the only way to describe the tempo of a composition. Yet after the metronome's invention, these words continued to be used, often additionally indicating the mood of the piece, thus blurring the traditional distinction between tempo and mood indicators. 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, indicates speed as such (while possibly connoting virtuosity, a connotation it did not acquire until the late 18th century).

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").

Understood tempos

In some cases (quite often up to the end of the Baroque period), conventions governing musical composition were so strong that no tempo had to be indicated. For example, the first movement of Bach's Brandenburg Concerto No. 3 has no tempo or mood indication whatsoever. To provide movement names, publishers of recordings resort to ad hoc measures, for instance marking the Brandenburg movement "Allegro", "(Allegro)", "(Without indication)", and so on.

In Renaissance music most music was understood to flow at a tempo defined by the tactus, roughly the rate of the human heartbeat. Which note value corresponded to the tactus was indicated by the mensural time signature.

Often a particular musical form or genre implies its own tempo, so no further explanation is placed in the score. Thus musicians expect a minuet to be performed at a fairly stately tempo, slower than a Viennese waltz; a Perpetuum Mobile to be quite fast, and so on. The association of tempo with genre means that genres can be used to imply tempos; thus Ludwig van Beethoven wrote "In tempo d'un Menuetto" over the first movement of his Piano Sonata Op. 54, although that movement is not a minuet. Popular music charts use terms such as "bossa nova", "ballad", and "Latin rock" in much the same way.

It is important to remember when interpreting these words that not only have tempos changed over historical time, and even in different places, but sometimes even the ordering of terms has changed. Thus a modern largo is slower than an adagio, but in the Baroque period it was faster[2].

Italian tempo markings

See also Italian musical terms used in English.

Basic tempo markings

From fastest to slowest, the common tempo markings are:

• Prestissimo - extremely fast (200 - 208 bpm)
• Vivacissimo - Very fast and lively
• Presto - very fast (168 - 200 bpm)
• Allegrissimo - very fast
• Vivo - lively and fast
• Vivace - lively and fast (~140 bpm)
• Allegro - fast and bright (120 - 168 bpm)
• Allegro Moderato - Moderately cheerful and quick
• Allegretto - moderately fast (but less so than Allegro)
• Moderato - moderately (90 - 115 bpm)
• Andantino - Alternatively faster or slower than Andante.
• Andante - at a walking pace (76 - 108 bpm)
• Adagietto - Rather slow (70-80 bpm)
• Adagio - slow and stately (literally, at ease) (66 - 76 bpm)
• Grave - slow and solemn
• Larghetto - rather broadly (60 - 66 bpm)
• Lento - very slow (60 - 40 bpm)
• Largamente/Largo - "broadly", very slow (40 bpm and below)
• Tempo commodo - at a comfortable speed
• Tempo giusto - at a consistent speed
• L'istesso tempo - at the same speed
• Non troppo - not too much (e.g allegro ma non troppo, fast but not too much)
• Assai - rather, very, enough as is needed (e.g Adagio assai)
• Con - with (e.g andante con moto, at a walking pace with motion)
• Molto - much, very (e.g molto allegro)
• Poco - a little (e.g poco allegro)
• Quasi - as if (e.g piu allegro quasi presto, faster, as if presto)
• tempo di... - the speed of a ...(e.g tempo di valse (speed of a waltz), tempo di marzo/marcia (speed of a march))

All of these markings are based on a few root words such as 'allegro', 'largo', 'adagio', 'vivace', 'presto' 'andante' and 'lento'. By adding the -issimo ending the word is amplified, by adding the -ino ending the word is diminished, and by adding the -etto ending the word is endeared. Many tempos also can be translated with the same meaning, and it is up to the player to interpret the speed that best suits the period, composer, and individual work.

N.B. Metronome markings are a guide only and depending on the time signature and the piece itself these figures may not be appropriate in every circumstance.

Common qualifiers

• assai - very, very much, as in Allegro assai (but also understood by some as "enough")
• con brio - with vigour or spirit
• con moto - with movement
• non troppo - not too much, e.g. Allegro non troppo (or Allegro ma non troppo) means "Fast, but not too much."
• non tanto - not so much
• molto - much, very, as in Molto Allegro (very fast and bright) or Adagio Molto
• poco - slightly, little, as in Poco Adagio
• più - more, as in Più Allegro; used as a relative indication when the tempo changes
• meno - less, as in Meno Presto
• poco a poco - little by little
• In addition to the common "Allegretto," composers freely apply Italian diminutive and superlative suffixes to various tempo indications: Andantino, Larghetto, Adagietto, Larghissimo.

Mood markings with a tempo connotation

Some markings that primarily mark a mood (or character) also have a tempo connotation:

• Agitato - Agitated, with implied quickness.
• Dolce - Sweetly
• Maestoso - majestic or stately (which generally indicates a solemn, slow movement)
• Morendo - Dying
• Sostenuto - Sustained, sometimes with a slackening of tempo.
• Vivace - lively and fast over 140 bpm (which generally indicates a rather fast movement)

Terms for change in tempo

Composers may use expressive marks to adjust the tempo:

• Accelerando - speeding up (abbreviation: accel.)
• Allargando - growing broader; decreasing tempo, usually near the end of a piece
• Meno Mosso - less movement or slower
• Mosso - movement, more lively, or quicker, much like 'Più Mosso', but not as extreme
• Più Mosso - more movement or faster
• Rallentando - slowing down, especially near the end of a section (abbreviation: rall.)
• Ritardando - delaying (abbreviation: rit. or more specifically, ritard.)
• Ritenuto - slightly slower; temporarily holding back. (Note that the abbreviation for ritardando can also be rit. Thus a more specific abbreviation is riten.)
• Rubato - free adjustment of tempo for expressive purposes
• Stretto - rushing ahead; temporarily speeding up
• Stringendo - pressing on faster

While the base tempo indication (such as "Allegro") appears in large type above the staff, these adjustments typically appear below the staff or (in the case of keyboard instrument) in the middle of the grand staff.

They generally designate a gradual change in tempo; for immediate tempo shifts, composers normally just provide the designation for the new tempo. (Note, however, that when Più Mosso or Meno Mosso appears in large type above the staff, it functions as a new tempo, and thus implies an immediate change.) Several terms control how large and how gradual this change is:

• poco a poco - bit by bit, gradually
• subito - suddenly
• poco - a little
• molto - a lot

After a tempo change, a composer may return to a previous tempo in two different ways:

• a tempo - returns to the base tempo after an adjustment (e.g. "ritardando ... a tempo" undoes the effect of the ritardando).
• Tempo Primo or Tempo I - denotes an immediate return to the piece's original base tempo after a section in a different tempo (e.g. "Allegro ... Lento ... Tempo I" indicates a return to the Allegro). This indication often functions as a structural marker in pieces in binary form.

These terms also indicate an immediate, not a gradual, tempo change. Although they are Italian, composers typically use them even if they have written their initial tempo marking in some other language.

Tempo markings in other languages

Although Italian has been the prevalent language for tempo markings throughout most of classical music history, many composers have written tempo indications in their own language.

French tempo markings

Several French composers have written markings in French, among them baroque composers François Couperin and Jean-Philippe Rameau as well as impressionist composers Claude Debussy and Maurice Ravel. Common tempo markings in French are:

• Grave - slowly and solemnly
• Lent - slowly
• Modéré - at a moderate tempo
• Vif - lively
• Vite - fast
• Très - very, as in Très vif (very lively)
• Moins - less, as in Moins vite (less fast)

German tempo markings

Many composers have used German tempo markings. Typical German tempo markings are:

• Langsam - slowly
• Mäßig - moderately
• Lebhaft - lively (mood)
• Rasch - quickly
• Schnell - fast

One of the first German composers to use tempo markings in his native language was Ludwig van Beethoven. The one using the most elaborate combined tempo and mood markings was probably Gustav Mahler. For example, the second movement of his Symphony No. 9 is marked Im tempo eines gemächlichen Ländlers, etwas täppisch und sehr derb, indicating a slowish folk-dance–like movement, with some awkwardness and vulgarity in the execution. Mahler would also sometimes combine German tempo markings with traditional Italian markings, as in the first movement of his sixth symphony, marked Allegro energico, ma non troppo. Heftig, aber markig.

Tempo markings in English

English indications, for example quickly, have also been used, by Benjamin Britten, amongst many others. In jazz and popular music charts, terms like "fast", "laid back", "steady rock", "medium", "medium-up", "ballad", and similar style indications may appear.

Rushing and dragging

When performers unintentionally speed up, they are said to rush. The similar term for unintentionally slowing down is drag. Unless practised by an experienced performer who "knows what he or she is doing", these actions are undesirable; dragging can often indicate a hesitance in the performer due to lack of practice; rushing can likewise destroy the pulse of the music. Because of their negative connotation, neither rush nor drag (nor their equivalents in other languages) are often used as tempo indications in scores, Mahler being a notable exception: as part of a tempo indication he used schleppend ("dragging") in the first movement of his Symphony No. 1, for example.

Can tempo terms be defined with the metronome?

Most musicians would agree that it is not possible to give beats per minute (BPM) equivalents for these terms; the actual number of beats per minute in a piece marked allegro, for example, will depend on the music itself. A piece consisting mainly of minims (half notes) can be played much more quickly in terms of BPM than a piece consisting mainly of semi-quavers (sixteenth notes) but still be described with the same word.

Metronome manufacturers usually do assign BPM values to the traditional terms, but these values are by no means correct for every piece.

Tempo markings as movement names and compositions with a tempo indicator name

Generally, composers (or music publishers) will name movements of compositions after their tempo (and/or mood) marking. For instance the second movement of Samuel Barber's first String Quartet is an "Adagio".

Some such movements may start to lead a life of their own, and become known with the tempo/mood marker name, for instance the string orchestra version of the second movement of Barber's first string quartet became known as Adagio for Strings. A similar example is Mahler's most famous work - the Adagietto from his Symphony No. 5. Another is Mozart's Alla Turca (here indicating the Janissary music type of mood of the final movement of Mozart's 11th Piano Sonata, K. 331)

Sometimes the link between a musical composition with a "tempo" name and a separate movement of a composition is less clear. For instance Albinoni's Adagio, a 20th century creative "reconstruction" based on an incomplete manuscript.

Some composers chose to include tempo indicators in the name of a separate composition, for instance Bartók in Allegro barbaro ("barbaric Allegro"), a single movement composition.

External links

• An accurate algorithm to measure the tempo using a digital computer
• Research group specializing in rhythm, timing, and tempo, University of Amsterdam
• Tempo indications in Mozart's music
• Tempo Terminology, Virginia Tech department of music
• Tempo variation among 300+ recorded performances of Beethoven's 'Eroica' Symphony
• Dolmetsch article on tempo

•  • [ e] Musical notation
Staff	Bar line . Clef . Key signature . Ledger line . Time signature . Rehearsal letter	Syncopation example
Notes	Accidental . Dotted note . Flat . Natural sign . Note value . Rest . Sharp . Slur . Tie
Expression marks	Articulation . Dynamics . Octaves . Ornaments . Tempo