Rhythm is a general term used to describe the motion of music in time. The fundamental unit of rhythm is the pulse or beat. Even persons untrained in music generally sense the pulse and may respond by tapping a foot or clapping.
Meter Signatures
Meter can be defined as a regular, recurring pattern of strong and weak beats. This recurring pattern of durations is identified at the beginning of a composition by a meter signature (time signature).
The upper digit indicates the number of basic note values per measure. It may or may not indicate the number of pulses per measure (as we will be see later in compound meters). The lower digit indicates a basic note value: 2 signifies a half note, 4 refers to a quarter note, 8 to an eighth note, and so forth.
Although meter is generally indicated by time signatures, it is important to realize that meter is not simply a matter of notation.
Simple Meter
In simple meter, each beat is divided in two parts (simple division). The upper numbers in simple meter signatures are usually 2, 3, or 4 indicating two, three, or four basic pulses. Some simple meters showing the division of the beat are shown below.
The basic pulse in simple meter will be some kind of a note value that is not dotted:
Compound Meter
In compound meter, each pulse is a dotted note, which is divided into groups of three parts (compound division). The upper numbers in compound meter signatures are usually 6, 9, and 12. In compound meter signatures, the lower number refers to the division of the beat, whereas the upper number indicates the number of these divisions per measure.
Duple, Triple, and Quadruple Meters
Both simple and compound meters will have two, three, or four recurring pulses. Meters are identified as duple if there are two basic pulses, triple if there are three, or quadruple if there are four. These designations are often combined with the division names to describe a meter. For example, 2 4 is a “simple duple” meter and 6 8 is a “compound duple” meter.
Asymmetrical Meters
The term asymmetrical means “not symmetrical” and applies to those meter signatures that indicate the pulse cannot be divided into equal groups of 2, 3, or 4 beats. The upper numbers in asymmetrical meters are usually 5 or 7.
Syncopation
If a part of the measure that is usually unstressed is accented, the rhythm is considered to be syncopated.
Dynamic Markings
Dynamic markings indicate the general volume (amplitude) of sound. Although imprecise, such marks denote approximate levels of intensity. The following words, abbreviations, and signs are common,
History
The notation of both pitch and duration has evolved over the centuries. It has been a gradual process of transformation that continues yet today.
Neumatic Notation
From about 650 to 1200, music notation consisted of a set of symbols called neumes (pronounced “newms”). These symbols took their name from the Greek word for gesture. Written above the Latin texts associated with the liturgy of the Christian church, neumes could not convey pitch or duration, but rather served as a memory aid in recalling previously learned melodic lines. Figure below is an example of neumatic notation from a twelfth century manuscript.
Horizontal lines were gradually added to indicate the locations of F and C. In the eleventh century, a four-line staff appeared that included the F line, the C line, and two additional lines. Later, neumes were square or diamond-shaped, as shown in Figure below. Combined with the staff, neumes could now indicate specific pitches. The four-line staff is still used to notate Gregorian chant.
Mensural Notation
Mensural (measured) notation, a system that included durational values as well as pitch, developed during the thirteenth century as the single melody and free rhythm of Gregorian chant or plainsong gave way to measured music that included parts, descant, and, later, harmony and counterpoint.
Present Notation
Our present system of notation evolved from thirteenth-century practices. A treatise on mensural notation, De Musica Mensurabili (Ars Cantus Mensurabilis), by Franco of Cologne (active 1250–1280), contains the fundamental rules of modern notation. Our notation system has developed gradually since the thirteenth century, and graphic details such as the shape of notes and clefs have changed. New symbols have been (and continue to be) invented as needed to better communicate the growing complexity of music.
Some Directions for Notation
Noteheads are oval in shape and positioned on the staff lines and spaces at a slight upward slant. Stems are thin, vertical lines that are directly connected to the head. The stems of single notes within the staff should be about one octave in length.
When a staff contains only a single melody, stems go down on those notes above the middle line and up on those notes below the middle line. When a note is on the middle line, the stem is usually down, except when the stems of adjacent notes are in the opposite direction.
When stemmed notes are placed on ledger lines, the stems should extend to the middle line of the staff,
When connected by beams, stemmed notes should be modified so that the beams are slanted to cross no more than one line of the staff for each group of notes. Beams are slightly thicker than note stems.
When two melodies occupy the same staff, the stems for one melody are up, and the stems for the other melody are down. This makes it possible to distinguish the melodies.
Beam groups of eighth notes (and smaller values) according to the beats in the measure.
In compound meter, it is important to show the basic pulse structure of the measure and the division (of three) as clearly as possible.
Use flags for eighth or shorter-value notes that are not grouped within a beat.
Connect no more than six notes by beams unless all are part of one beat.
Flagged and beamed notes are generally not mixed, except when notating vocal music. In vocal music, flagged notes have traditionally been used when the text–music relationship involves one note for each syllable. However, modern practice has moved toward the use of “instrumental” notation for vocal music.
Irregular divisions of a beat or measure are indicated by showing the number of notes in the resulting group by means of an Arabic numeral. The note values of the irregular group are notated the same way as the regular group, provided the number of notes in the irregular group is less than twice that of the regular. For example, a triplet retains the same note values as a regular duplet.
When the number of notes in the irregular group is more than twice the number of the regular, then the next smaller note value is used; for example, a quintuplet would employ the next smaller note value.
The whole rest can be used to indicate a full measure of rest in any meter.
Use two quarter rests rather than a half rest in 3 4 meter.
When notes of a chord are on an adjacent line and space, the higher of the two is always to the right, regardless of the direction of the stem.
When a dotted note is on a line, the dot is usually placed slightly above the line. When two separate voices are placed on a single staff, the dots are below the line on the notes with stems down.
Dynamic markings should be added above, between, or below staves according to the nature of the music or score:
Instrumental Music : The markings in instrumental music are usually placed beneath the staff to which they refer. Sometimes, because of inadequate space, it is necessary to place markings above the staff.
Vocal Music : Vocal music markings are usually placed above the staff to which they refer. This is done to avoid confusion with the words of the text.
Piano Scores : The markings in piano scores are placed between the staves if the markings are to apply to both staves. If markings are needed for each staff individually, the markings should go just above or below the staff to which they refer. Markings should not be placed on the staff, although the crescendo and diminuendo will protrude into the staff on occasion.
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