Timing in Jampea
Jampea is a Digital Audio Workstation, where you can create music, edit music, or just listen to existing music, created by someone else (and analyze the structure of that music).
When you open a piece of music in Jampea, you can see tiny rectangles, which are various events that happen in this piece (e.g., a drum hit). As we go from left to right, we go through time (if an event is more to the left, it will happen sooner). The vertical location of an event represents the pitch of a sound (moving one step higher on the screen is moving one semitone higher in pitch).
Below, we can see a screenshot of a musical piece. There are purple events ("long" tones F and C) and dark blue events ("short" tones F, D#, G and C).
Beats
In music, various sounds can be heard over time. E.g., a drum could be heard twice per second. A violin starts playing the G3 tone five seconds from the beginning and stops two seconds later, and so on. How can we write it down?
Time in music is measured in beats. There is a regular grid of beats (vertical lines) in Jampea, and we can place events into it. The grid is marked with the green color in the image above. It allows us to create repeating sound patterns, as we can align the events nicely into our grid. We should also specify the tempo (the speed of playing) in beats per minute (BPM). A tempo of 120 BPM means that 120 beats are played per minute, i.e., two beats correspond to one second of time. Later, we can speed up or slow down our music simply by changing the BPM value while keeping all the events at the same place.
Measures (Bars)
Beats are joined together into measures, also called bars (the measure grid is marked with red in the image above). Usually, there are either three or four beats in a measure. This new grid helps us navigate our music even better. Events in each measure are very similar to a previous measure (tones or drums are played in a similar pattern).
If we want to play tones C, E, G ... in a loop, equally spaced in time, it makes sense to have three beats per measure. But if we want to play C, E, G, E ... in a loop, it makes more sense to use four beats per measure.
Even Smaller Steps
Take a look at the example below. There is a clear drum pattern - a drum hit at the beginning of every beat (gray color). But what is happening with the tones that are played (blue)?
The author divided each beat into four equal parts and placed the melody into these little "sub-beats". We can imagine a much smaller regular grid, which divides each beat into four parts, and the melody is aligned to this smaller grid.
In practice, we can split the beat into two equal halves and repeat this process of splitting as much as we want (to get 4, 8, 16, 32 ... parts inside one beat). Tones in music are never placed randomly. The beginning and the end of each tone are always aligned to a regular grid that was created by splitting a beat into two parts several times.