Review 1.4

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Pulse

Music is based on reoccurring groups of pulses. These groups usually consist of three or four pulses.

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Time Signature

The time signature tells us how many pulses or beats are in the basic pattern and which note value represents one beat.

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Denominator

The denominator in a time signature tells us which note value represents one pulse.

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Numerator

The numerator in a time signature tells us how many pulses per pattern.

Notatio Rhythmica

rhythmic notation

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Rhythmic Notation indicates when to sound a note and when to remain silent. Silence is indicated by "rests" found on the left side of the graph, and sound by the "notes" on the right.

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Using a system of note/rest durations, musical rhythm is written in "Bars". A "Bar" refers to a recurring amount of pulses such as 3 or 4.

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Bar-lines separate the reoccurring groups. Within the bar-lines, all beat must be accounted for whether sounded or silent.

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A composer may combine or divide beats by using different combinations of note/rest durations; however each bar must represent the exact amount of pulses indicated with the time signature and may not contain more or less.

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3/4 must have exactly three beats in every bar; 4/4 must have four.

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The note durations are related by ratio based on 4/4 time. Regardless of the time signature, a whole note will always represent 4 pulses, a half note 2 et cetera.

 

whole bar 1:1

half bar 1:2

quarter bar 1:4

eighth bar 1:8

sixteenth bar 1:16

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The tempo or speed of the music determines how many pusles per minute.

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The time signature assigns how many pulses per group, and which note duration represents one pulse.

 

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Metres Musicales

musical metres

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The most common used music metres are 3/4 and 4/4.

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Triple Metres:

3/4, 6/8, 9/8

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Accent

one 2 3 | one 2 3 | one 2 ...

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National Anthem

3/4

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Happy Birthday

3/4

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Notice the difference in "feel" or the accent between groups of 3 (3/4) and groups of 4 (4/4)

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Duple Metres:

2/4, 4/4, 6/8, 12/8

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Accent:

one 2 3 4 | one 2 3 4 | one ...

 

America The Beautiful

4/4

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Tempus

tempo/time

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Pulses per minute

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60 = quarter note

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This means that in one minute, there will be 60 pulses, and the quarter note duration represents one pulse.

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The speed of the music is not determined by the note duration.

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A melody written in whole notes can be the same speed as the same melody written in sixteenth notes.

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60 = Sixteenth note

60 = Whole note

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Music speed only and solely depends of the tempo which may be set to any note duration.

Triplex

triplet

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A triplet is to play three notes in the space two.

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The change in feeling between two notes and three notes is equivalent to using squares versus triangles and it has a pronounced impact on the human ear.

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Consider 6/8 and 9/8 time signature.

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In 6/8, there are three main pulses with two subpulses (2x3 = 6 total pulses)

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In 9/8 time, there are three main pulses with three subpulses (3x3 = 9 total pulses).

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If the pulses were set to the same tempo; then 6/8 would have two subpulses per beat, and 9/8 would have three subpulses per beat.

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Exercise:

With your left hand snap once per second. This is tempo=60.

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With your right hand, snap twice for every snap with your left hand.

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Your right hand is tempo=120 (2x60)

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Now snap thrice (three times) for every snap with your left hand.

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Your right hand is tempo=180 (3x60)

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Notice the difference between duple (two) and Triple (three).

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