This study guide summarizes the Unit 3 concepts from the provided photos. It is a paraphrased review, not a transcription of the textbook.
Core Idea
Rhythm organizes music in time. The most important elements are duration, accent, and grouping. Meter gives those elements a recurring framework of strong and weak beats, while rhythm can either cooperate with that framework or push against it.
Beat and Tempo
The beat is the basic pulse by which musical time is measured. A listener can often sense the beat even when the surface rhythm is more active or varied.
Tempo is the speed of the beat. Note values are relative, not absolute: a quarter note in a fast tempo lasts less time than a quarter note in a slow tempo, but it still relates proportionally to eighth notes, half notes, and other values within that tempo.
Duration, Division, and Combination
The notation system divides and combines durations. In the simplest divisions:
- A whole note divides into two half notes.
- A half note divides into two quarter notes.
- A quarter note divides into two eighth notes.
- An eighth note divides into two sixteenth notes.
Rests follow the same proportional system. Dots extend a duration by half of the preceding value; a second dot adds half the value of the first dot. Tuplets, especially triplets, divide a beat or duration into a number of parts that does not match the ordinary division.
Ties combine durations. They can carry a sound across a bar line, create a duration that dots cannot express clearly, or clarify rhythmic grouping.
Accent
Accent means emphasis. Accents may arise from performance or from the musical surface itself. Common sources include:
- Dynamic stress
- A note's beginning or attack
- Long duration, often called agogic accent
- Unusually high or low register
- Dissonance or chromaticism
Accent is not identical with meter. A note can be rhythmically accented while occurring in a metrically weak place.
Meter and Time Signatures
Meter is a repeating pattern of accented and unaccented beats.
- Duple meter groups beats by twos.
- Triple meter groups beats by threes.
- Quadruple meter is derived from duple and has a primary accent on beat 1 and a secondary accent on beat 3.
The bar line normally appears just before the strongest beat of the measure. The accent on beat 1 is the metrical accent.
Time signatures indicate the meter. The upper number usually gives the number of beats or beat-divisions in the measure, while the lower number indicates the notated value being counted.
Simple and Compound Meter
Simple meters divide the beat into two equal parts. Compound meters divide the beat into three equal parts and usually notate those beat divisions with upper numbers such as 6, 9, or 12.
In a quick 6/8, listeners often hear two main beats, each divided into three eighth notes. In a slow 6/8, the six eighth notes may be felt more individually as two groups of three.
Meters with five or seven beats, as well as changing meters, are common in much twentieth-century music and can be understood as combinations of duple and triple groupings.
Rhythmic Accent and Syncopation
When rhythmic accents align with metrical accents, the rhythm feels natural and stable. When a rhythmic accent contradicts the meter, the result is syncopation.
A common syncopation begins on a weak beat or weak part of the beat and is held through the following strong beat or strong part. The attack is heard as stronger than the continuation, so the meter and rhythm conflict.
Hemiola is a special rhythmic effect in triple or compound meters where two groups of three are temporarily heard as three groups of two.
Rhythmic Groups
Notes gather into small rhythmic figures or groups. A group may begin on a strong beat, begin before the strong beat, or extend over more than one bar. Groups can also overlap when the last note of one group also begins the next.
Measure Groups, Hypermeter, and Phrase
Meter can operate above the level of the measure. A hypermeasure is a group of measures that behaves like a larger measure, with stronger and weaker bars.
Four-bar hypermeasures are common, often combining two two-bar groups. Three-bar groups and asymmetrical five-, six-, or seven-bar groups can also occur.
A phrase is a rhythmically and tonally coherent unit. Phrase endings often coincide with tonal goals, such as arrival on tonic.
Rhythm and Dissonance Treatment
Dissonance has rhythmic as well as intervallic behavior. Passing and neighboring tones usually occur on weak beats or weak parts of the beat. When such tones occur in strong positions, they are accented passing tones or accented neighboring tones. Accented incomplete neighbors are often called appoggiaturas.
Suspensions are accented dissonances created when a tone is held or prolonged into the next harmony. They typically involve preparation, accented dissonance, and resolution.
Anticipations work in the opposite direction: a tone arrives early, before the harmony to which it belongs. It may be held into the following harmony or restruck there.
Memory Targets
- Define beat, tempo, duration, accent, rhythm, and meter.
- Know how note values, rests, dots, tuplets, and ties work.
- Distinguish rhythmic accent from metrical accent.
- Identify duple, triple, quadruple, simple, and compound meters.
- Explain syncopation and hemiola.
- Recognize rhythmic groups and overlapping groups.
- Understand hypermeasure and phrase.
- Know how rhythm affects dissonance treatment, especially suspensions, appoggiaturas, and anticipations.