Grove Music Online "Rhythm": Fundamental concepts & terminology -I

Justin London. "Rhythm." Grove Music Online. Oxford Music Online.  http://www.oxfordmusiconlin.com/subscriber/article/grove/music/45963pg4 (accessed February 24, 2011)

1. Fundamental concepts and terminology

.....this discussion begins with the duration of single notes, then proceeds to the organization of successive durations into coherent groups, the emergence of metre and metric listening, and so forth. In addition, since rhythm and metre are coherent phenomena only for a listener who can capture and remember the music as it unfolds, the following discussion engages psychological theory and research.....

1-1 The distinction between rhythm and metre.

A series of events is commonly characterized as 'rhythmic' if some or all of those events occur at regular time intervals. But being 'rhythmic' is not the same thing as being 'a rhythm'. For a musician or musicologist 'rhythm' signifies a wide variety of possible patterns of musical duration, both regular and irregular. ..... While all music involves some type or [sic] rhythm, not all music involves metre. Thus in common usage the adjective ‘rhythmic’ often signifies what might more precisely be described as a ‘metrically regular series of events’. ….. irregular rhythms can occur in the context of a regular meter (e.g. syncopated figures and asymmetrical phrase structures), ….. not all metres require regular or even patterns of duration (e.g. Brtók’s ‘Bulgarian’ rhythms).

…..rhythm involves the structure of the ‘temporal stimulus’, while metre involves our perception and cognition of such stimuli.

1-2 The perception of duration and succession.

…..there are a number of psycho-physical limits on our ability to perceive durations and durational succession. Hirsh (I1959) demonstrated that tow onsets music be separated by a t least two milliseconds (ms)in order to be distinctly perceived, and that at least 15-20ms are required to determine which onset came first. 50ms perceptual decay time-a minimum interval needed to hear on element follow another without overlap. …..100ms seems to be the threshold for reliable judgments of length, …..is thus the minimum duration that engages a ‘musical’ understanding of sound…..

…..duration differences may be perceived as differences in intensity or loudness…..

1-3 Durational patterns and rhythmic groups.

…..

Two or more musical durations may cohere into a larger unit, termed a ‘rhythmic group’. The creation of coherent, well-articulated rhythmic groups is one of the principal tasks the performer faces in realizing a musical score: to project a sense that some notes go with other notes, and that these groups themselves from larger units. From this process that basic musical shapes of a piece may be discerned.

1-4 Metre: beats, metric cycles and tempo.

Metre is a structured attending to time which allows the listener to have precise expectations as to when subsequent musical events are going to occur. …..

First and foremost, metre requires an awareness of a beat or pulse. ….. Only when we hear a series of regular articulations in a certain range (from 100ms to 2 seconds apart) does a sense of pulse arise. More familiarly, a 2-second duration is a semibreve at a tempo of crotchet = 120 (the upper limit), while a 100ms duration is a semiquaver at a tempo of crotchet = 150 (the lower limit). ….. ‘maximal pulse salience’ (from 60 to 150 beats per minute, anchored at approximately 100 beats per minute) wherein pulses tend to be most strongly felt.

…..beats as primary components of the measure, while various subdivisions are produced by analogous partitions of the beat. Weber (D1817-21), with an emphasis on symmetry as an organizing principle, noted that Just as beats together form small groups, several groups can also appear bound together as beats of a larger group, of a larger or higher rhythm, a rhythm of a higher order. ….. Thus Weber extended metric relationships both upward and downwards, as opposed to earlier theorists who had begun with the measure and then had proceeded by division. …..

Given the emphasis on symmetry and the pervasiveness of the systole/diastole metaphor for musical motion, 19th-century accounts of metre were strongly biased towards binary principles of metric organization. ….. Cooper and Meyer define metre as ‘the measurement of the number of pulses between more or less regularly recurring accents’ (E1960, p.4.)

Lerdahl and Jackendoff note that “fundamental to the idea of meter is the notion of periodic alternation of strong and weak beats’ and that ‘for beats to be strong or weak there music exist a metrical hierarchy—two or more levels of beats’ (E1983, p.19). …..Kramer (K1988) relaxes these constraints and allow for the non-isochronous spacing of beats and hyperbeats (though they still must occur in cycles of twos or threes).

The beat level of the metric hierarchy serves as the temporal anchor for the other levels. ….. Rather, a sort of ‘middle-out’ perspective on metre seems most consonant with the way we attend to (as well as represent) rhythmic events.

…..Thus the presence of metric notation does not guarantee the presence of a metre.

1-5 Rhythmic and metric accent.

….. Originally, qualitative accent referred to poetic rhythms whose elements were differentiated by dynamic or intonation stress, as distinct from those differentiated by length. …..

A metric accent marks one beat in a series as especially strong or salient, such that it functions as a downbeat, while a rhythmic accent makes on element in a series of durations the focal member of the rhythmic group. …..

The relationship between tonal motion and rhythmic and metric accent(s) has generated a considerable amount of discussion, much of it focusing on the accentual status of cadences and other components of phrase structure. ….. Not surprisingly, from a Scenkerian perspective rhythmic accent is generated via top-down linear processes, as it derives from tonal motions which serve to articulate various structural levels.

.....Epstein distinguishes stress, rhythmic accent and metric accent.  He places metre and rhythm into separate temporal domains, a 'chronometric time' consisting of beats and metric accents, and an 'integral time' which contains pulses and rhythmic groups.  Lerdahl and Jackendoff distinguish three varieties of accent:.....'give emphasis or stress to a moment in the musical flow.....sudden changes in dynamic or timbre, long notes, leaps....'caused by melodic/harmonic points of gravity in a phrase or section', .....'beat that is relatively strong in its metrical context'.

Only lists the fundamental terms and concepts one should be familiar to be able to start the discussion of musical rhythm.  The last 3 parts where states the interactions, complex of rhythm and metre, and the additive/divisive nature are more technical which appears less useful at this stage.  However, it still didn't give enough information about how 'time' is valued in a musical sense from this part of writing. Hoping the later section where talks about the oriental notion about rhythm/metres will really touch upon this topic.