Basic Music Series
Lesson I.6 Rhythmic Notation
I.6.A
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.
I.6.B
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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I.6.B
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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I.6.C
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.
I.6.D
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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BMS EPISODE I.6
