Musical Bar Line is a kind of division of the song in intervals of same length of time, with the aim of organizing the structure and make the orientation to the musician easier. This interval of time is represented by vertical bars, as the example below (highlighted in orange):
Example of Musical Bar Lines
In this example, what kind of organization was used for the musical bar lines? It was separated by groups of 4 crotchets. This means that in each space fits 4 crotchets. This is the defined interval of time for each musical bar line, wherein it could have other figures here in the middle, check it:
In this example, pay attention in the second musical bar line. There are a lot of musical figures (crotchets, 16th notes and 32th notes) on it, but all of them together fit the time of 4 crotchets; so, they stay in the same bar line. The same happens to the bar lines 1 and 3, that have other musical figures with the equivalent time of 4 crotchets.
Moral of the story: To say “it fits 4 crotchets in one bar line” doesn’t mean that a bar line can only have crotchets figures. This reference only gives the time which is related to the bar line, regardless the figures that are there.
Ok, but who defines the time/length of a bar line? Where is written that in each bar line you will have a length of 4 crotchets?
Bar Line Fraction
Check this fraction below, which appears in the beginning of the sheet music that we saw:
This fraction 4/4 determined that the bar line would have 4 crotchets. Let’s find out the meaning of it:
The fraction denominator:
Informs which figure will serve as reference to the analysis. The number 4 refers to the crotchet, so this is the figure of reference. And the numerator:
Informs how many figures fit inside each bar line. Notice that the numerator of this fraction is saying that it fits 4 figures in 1 bar line, and the denominator is saying that this figure is the crotchet; so the fraction 4/4 informs that it fits 4 crotchets in 1 bar line.
Check below the numbers that represent each figure of the denominator, besides the crotchet:
1 – Semibreve
2 – Half note
4 – Crotchet
8 – 8th note
16 – 16th note
32 – 32th note
64 – 64th note
Let’s work some examples of fractions (take them as exercise) so it will be clear for you to know how many figures fit in each bar line:
4/4 = 4 Crotchets
4/2 = 4 Half notes
4/8 = 4 8th notes
2/4 = 2 Crotchets
3/1 = 3 semibreves
5/32 = 5 32th notes
7/2 = 7 Crotchets
How to define a bar line in a song
The defined time to each bar line is related to the beat that the song has. Try to take some sheet music, listen to them and verify its fraction in the bar line. You will see that the bar line is marking: the rhythm of the song, the form as the instrument players are dividing the chords or, simply, the rhythmic pattern that the melody follows.
Some music genres generally presume which will be its time. The Waltz, for example, has a time of 3/4. As a general mode, the most common time to appear in sheet music is, with any doubt, 4/4. But there are innumerous possibilities of time, don’t limit yourself to playing only “smooth” times. Read the article “Rhythm – Theory” here in the website to train your musicality in more complex times. This will enrich your vision, besides preparing you for varied repertoires in a rhythm and musical bar lines point of view.
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