02 MIDI Performance

MUSC 108. Introduction to Music Technology - Fall 2013

02 MIDI Performance

In order to create a musically convincing performance using the MIDI language you have to control the duration, tempo, dynamics, phrasing, and articulations of individual notes and groups of notes. You should approach the realization of the MIDI performance with the same interpretive analysis of the music that a conductor or concert artist would use. Instrumental technique is not a barrier to a refined MIDI performance.

Elements of Performance			MIDI Specification with annotations
Category	Description	Notation	MIDI Realization
Articulation	Technique Touch Breathing Duration Accent Stress	legato staccato slur symbols sfz > (accent) - (tenuto) sfz	Note-On (NON) Note-Off (NOF) velocity (data 2 byte) duration
Dynamics	Loud / soft Intensity Increase/decrease Swell	fff - ppp cresc. decresc. hairpins	velocity (data 2 byte) volume control (controller 7) expression control (controller 11) ADSR envelope (Attack-Decay-Sustain-Release) over the duration of the note. Often built in to the sound.
Phrasing	Breathing Musical "sentences" Self contained musical ideas	curved line comma (,)	phrase endings can be softer, with less than than indicated note duration, producing a slight breath or separation a subtle slowing down can occur at the end of a phrase a new phrase can begin with a different dynamic level a common phrase dynamic is to get louder 2/3 of the way through the phrase and get softer for the last third
Rhythm and Tempo
Category	Description	Notation	MIDI Realization
Pulse or Beat	An external time source that marks off equal units of time Heartbeat Metronome		The computer clock keeps accurate time to the microsecond while MIDI is usually in timed to the millisecond
Beat Unit	The note value chosen by the performer to represent one beat of the external pulse	Time Signature (usually but not always)	arbitrary could be quarter note, or a half note, or a dotted quarter note depending on the music.
Tempo	The speed of the pulse	M.M. = 60 (60 beats per minute or one beat every second) Adagio, Andante, Allegro, Presto (text indications of the tempo)	If a quarter note = 1000 ms then an eighth note = 500 ms If a quarter note equals 480 PPQ then an eighth note = 240 PPQ
Rhythm	The mathematical proportion between note values The relative length of one note to another note Independent of tempo	quarter note = two eighth notes = four sixteenth notes, etc.	note proportion math independent of the tempo
Note duration	The absolute time duration of a note. In MIDI these durations are usually expressed in milliseconds You need to know the tempo and the notated rhythm value to calculate the duration of a note in milliseconds	quarter note = two eighth notes = four sixteenth notes, etc.	computer clock time math depends on the tempo as well as the notated rhythm value
Meter	The grouping of notes into patterns of stressed and unstressed notes, most commonly in twos, threes, and fours	Time Signature Simple Meter where each each beat is subdivided in twos; e.g. 3/4 time Compound Meter where each beat is subdivided into threes; e.g. 6/8 time	velocity is usually used to express metrical accents and provide rhythmic drive
Rubato	The performer may speed up or slow down for interpretive purposes	ritard a tempo accelerando fermata	math based on changing the duration of the beat unit over several notes or measures
Swing	The performance of written eighth notes in a long-short feel instead of the both notes equal feel.	"Swing" indicated at beginning of score. Assumed in jazz Indication stating that 2 written eighth notes represent a triplet quarter eighth.	duration, velocity In "straight eighths" each eighth note would get 1/2 the length of a quarter note. In "swing eighths" the first eighth note would get 2/3 the length of a quarter note and the second eighth would get 1/3 the length.
Mixing
Balance	Relative volume of each instrument	na	volume controller 7 expression controller 11
Pan	Position of each instrument in the left-right stereo field	na	pan controller 10

Performance Symbols

Several performance symbols are used in music.

Name	Symbol	Comments	MIDI Performance
None		No articulation markings. The notes are played normally.	Duration would be approximately 80% - 90% of written value.
Phrase		A phrase is a curved line connecting more than two notes. The notes are played as legato (smoothly connected) as possible.	The note duration would be 90%-105% of the written value.
Slur		A slur is a curved line connecting exactly two notes of different pitch. The notes are connected smoothly together. The second note is softer and shorter than the first.	The duration of note 1 would be 90%-100% of the written value. The duration of note 2 would be approximately 60%-80% of the written value. The velocity of note 2 would be approximately 50%-80% of note 1.
Staccato		A staccato note is played in a short, crisp, and detached style.	The duration of a staccato note would be about 5%-15% of the written value.
Accent		An accented note is played louder than its surrounding notes.	The velocity would be 10%-30% louder than its immediate neighbors. Remember the maximum velocity is 127.
Fermata		A fermata (bird's eye) over a note indicates the note's duration is longer than its written value.	The additional duration is at the discretion of the performer.
Crescendo		Getting louder	The MIDI velocities would gradually increase over a range of notes.
Decrescendo		Getting softer	The MIDI velocities would gradually decrease over a range of notes.
Comma		Breath mark	The duration of the note before the breath mark is shortened. A slight delay may take place before the next note is played.
Tenuto		Emphasize, sustain	Increase in duration and velocity.
(Phrase Release)		Last note is softer and slightly shorter than true value to allow for breath between phrases	Decrease in duration and velocity of last note.
Ritard	rit.	Gradual slowing down	Duration between NON's increases.
Accelerando	accel.	Gradual speeding up	Duration between NON's decreases.
A Tempo	a Tempo	Back to the original tempo. Used following a ritard or accelerando.	Duration between NON's increases.
Rubato	rubato	Free tempo. The performer may speed up or slow down at his/her discretion for musical effect.	Duration between NON's increases and decreases.

Articulation

Articulation refers to the performer's attack, sustain and release of the note. A pianist articulates a note with his/her touch, a wind player articulates a note with his/her tongue and breath pressure.

Phrases, Ties, Slurs

A curved line connecting two or more notes can have three distinct meanings: phrase, slur, or tie.

Phrase

A phrase is used to indicate the group of notes is to be played as legato (smoothly connected) as possible.

Slur

A slur connects two notes of different pitch. Every instrument has its own technique of playing slurs. The general effect is that the second note is softer and slightly shorter than the first note.

Tie

A tie connects two notes of the same pitch on the same line or space. Only the first tied note is played. The total duration of the tied note group is equal to the sum of the individual note values.

Dots

A dot associated with a note can have two distinct meanings: augmentation or staccato.

Augmentation

Augmentation dots increase the duration of a note or rest by 50%. An augmentation dot is always placed in the space to right of note head. If note has a flag, the dot is placed to right of flag

Staccato

A staccato dot is placed directly above or below the note head. Staccato means that the duration of the note is to be played as short as possible.

Accents

The symbol is an accent. A note with an accent is played more forcefully than its neighbors. A sudden strong accent is called sforzando and is indicated by this symbol .

Tenuto

The tenuto symbol – is the opposite of staccato. It means the note is to be slightly stressed or "leaned on" making sure it gets its full duration. It does not imply an accent.

Comma

A comma is used to indicate a break in the phrase. A deliberate breath or silence between phrases.

Fermata

A fermata indicates an indefinite pause. The performer determines how much time to give to the pause. Fermatas are placed above or below the staff as shown in the following example.

[Overview] [Syllabus]

Revised John Ellinger, January - September 2013