Second Music Lesson
Melodies, Beats, Bars, Timeline, Notes
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A melody is a sequence of sounds. Each sound has its own frequency and duration. In the previous lesson you have got to know a very simple melody: Scale C Major.
This melody consists of the following sounds: C, D, E, F, G, A, B, C1, each of equal duration.
Now we will present the well known melody of Frere Jacques (Brother John).
This melody consists of the following sounds: C1, D1, E1, C1, C1, D1, E1, C1, E1, F1, G1, E1, F1, G1, G1, A1, G1, F1, E1, C1, G1, A1, G1, F1, E1, C1, D1, G, C1, D1, G, C1. But in this melody some sounds have different duration than others. Not all are of equal duration.
Now we will establish the exact relative durations of the sounds in this particular melody. In order to do this we will devide this melody into 16 equal parts, each of them indicated by a short punch of percussion at the begnning.
To say what is the duration of a particular sound we must have some basic time measure. There is such a basic time measure in music. One beat. There is no constant number of milliseconds that one beat lasts. This is because one melody can be played faster or slower, depending on what we wish. Each time we can decide how many beats per minute we want to have. In our Frere Jacques melody there are 120 beats per minute what gives us 1 beat = 500 milliseconds. Each of our 16 parts lasts exactly 2 beats, so we have a punch of percussion with beats 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31 - every second beat.
Let analyse our Frere Jacques melody. We can hear that between 1st and 2nd punches of percussion there are two sounds of equal duration. So each of them lasts 1 beat. Then we have the same situation between 2nd and 3rd, 3rd and 4th, 4th and 5th punches of percution. So first 8 sounds are of the same duration and each of them lasts 1 beat. Then between 5th and 6th punches of percussion there are still two sounds of equal duration (so they last still 1 beat), but between 6th and 7th punches of percussion there is only one sound, so this sound lasts 2 beats. This scenario repeats between 7th and 9th punches of percustion: two sounds of equal duration between 7th and 8th and one sound between 8th and 9th. Then situation suddenly changes. Between 9th and 10th punches of percussion we have 4 sounds of equal duration, so each of them lasts 1/2 beat, then between 10th and 11th punches of percussion we have again two sounds of equal duration (so each of them lasts 1 beat). This scenario repeats between 11th and 13th punches of percussion: we have 4 sounds of equal duration between 11th and 12th and two sounds of equal duration between 12th and 13th. Then between 13th and 15th and between 15th and the end of the melody we have the same situation as between 5th and 7th and between 7th and 9th. Two sounds - each of them lasts 1 beat and then one sound that lasts 2 beats.
We can write down our research on the timeline. Sounds are represented by green marks whose lengths are proporcional to the durations of sounds. There was no need to place signs denoting the punches of percussion on this timeline. We can easily place them in mind on each vertical bar and exactly in the middle between them.
You should notice that the melody Frere Jacques presented on the above picture has a very interesting semantic structure. Each second part of it is repeated, and this in fact is the main reason why we consider them as parts. This observation leads us to the concept of bar. A bar is a segment of time defined as a given number of beats. When you listen to a melody you can tell what is the number of beats in one bar mainly because of its semantic structure, however itís not always so simple as in our Fere Jacques melody. For now it is good enough to think that this matter is connected to some cyclic elements in melody that establish its rhythm.
In our case, there are 4 beats for one bar. So you can hear two punches of percustion during one bar. Now we can say that the punch of precussion is on the 1st and 2nd beat of each bar. On the above picture each bar is marked by the vertical bar at the end it.
Now you can see this melody in a classic five-line staff notation.
If you understand our notation on the timeline with green marks, you will easily understand this notation. The main hint is that the sound frequency in encoded by the possision of a note on the five-line staff and the duration is encoded by its shape. The meaning of vertical bars is the same as on the previous picture.
Notes have theirs names. This is a whole note. This is a half note. A whole note duration is equal to the duration of two half notes. This is a quarter note. A half note duration is equal to the duration of two quarter notes. This is an eighth note. A quarter note duration is equal to the duration of two eigth notes. This is a sixteenth note. An eighth note duration is equal to the duration of two sixteenths notes.
These two numbers just after the clef have the following meaning. The lower number indicates the note whose duration is equal to one beat (1 - whole note, 2 - half note, 4 - quarter note, 8 - eighth note, 16 - sixteenth note). The upper number indicates the number of beats per bar. So everything is correct. In our Frere Jacque melody we have 4 beats per bar, and one quarter note is equal to one beat. You can look at the first bar on the picture above - there are exactly four quarter notes.
Now if you are interested in the way how frequency is encoded by position on the five-line staff take a look on the picture below. Note that the sharp mark on given position increases the frequency by one semitone.
This is only our first approach to the classic five-line staff notation. It includes many more symbols, but we think that this is a good starting point.
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