{{Unreferenced, date=March 2017
A tempo map is a part of a
MIDI
MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...
file. Musical events occur as a succession of events in time, whose speed is
tempo
In musical terminology, tempo (Italian, 'time'; plural ''tempos'', or ''tempi'' from the Italian plural) is the speed or pace of a given piece. In classical music, tempo is typically indicated with an instruction at the start of a piece (often ...
. Music also organizes these according to a framework called
meter
The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its prefi ...
, by partitioning time into patterns of "strong" and "weak" beats. MIDI's tempo map specifies the speed at which a file's events are transmitted within this framework: their tempo. If a file plays at a fixed tempo, its map is a horizontal line (e.g., measures 38 and 39 in this part of a MIDI
sequencer
Sequencer may refer to:
Technology
* Drum sequencer (controller), an electromechanical system for controlling a sequence of events automatically
* DNA sequencer, a machine used to automatically produce a sequence readout from a biological DNA sam ...
’s display of the end of J.S. Bach's prelude #8 from Book I of the
Well-tempered Clavier
''The Well-Tempered Clavier'', BWV 846–893, consists of two sets of preludes and fugues in all 24 major and minor keys for keyboard by Johann Sebastian Bach. In the composer's time, ''clavier'', meaning keyboard, referred to a variety of in ...
):
But, if the tempo fluctuates as a function of time, such as in ''
accelerando
''Accelerando'' is a 2005 science fiction novel consisting of a series of interconnected short stories written by British author Charles Stross. As well as normal hardback and paperback editions, it was released as a free e-book under the CC ...
'', ''
allargando'', or ''
rubato Tempo rubato (, , ; 'free in the presentation', literally ) is a musical term referring to expressive and rhythmic freedom by a slight speeding up and then slowing down of the tempo of a piece at the discretion of the soloist or the conductor. Rub ...
'', the line is respectively an upward- or downward-climbing one, or in the latter case, a complex curve, as seen here in measures 35 and 36 at left, or the ending in measures 40 and 41.
In most music, aesthetics demand that this flow of events not be linear, but fluctuate according to the expression the music intends to convey. Hence, a very emotional piece such as the preceding is excerpted from, although playing at a base tempo of MM=50 — which means 50 quarter notes per minute, holding back or lunging forward according to expressive impulse can result in a tempo map similar to that seen above: It flexes tempo down for the intermediate cadence at left, and again for the final
allargando at the right.
After recording a sequence in real time at a fixed tempo, or composing it using step-record mode, well-written
MIDI sequencer
A music sequencer (or audio sequencer or simply sequencer) is a device or application software that can record, edit, or play back music, by handling note and performance information in several forms, typically CV/Gate, MIDI, or Open Sound Cont ...
software like
MasterTracks Pro
Master Tracks Pro (MTP) is music-sequencer software for Windows, to author and/or edit MIDI data. David Kusek and Don Williams ''et al.'' at Passport Designs originally created it, continuation of marketing and development by GVOX, and, as of ...
will have functionality to edit the MIDI tempo map, so as to result in a natural, expressive result, not a machine-like one, when playing the file.
MIDI