Music notation is a discrete system. This means that notes written on the staff can only have fixed values of pitch and duration. While fixing pitch values is required for tempered instruments such as guitar, if the musicians performed with exact fixed timing their performances would sound too mechanical, as they were generated by computer.
While in the earlier history of the Western music the musicians did strive for strict timing, ever since 18th century the musical educators recommended all kinds of tempo modifications to be used in performances. There were two schools of thought, one that advised stable overall tempo and only duration of notes be adjusted to fit performer's expression, while others advised more free approach. The first approach gave rise to the development of tempo rubato where some notes are prolonged at the expense of others, while the second resultred in many other tempo modification practices.
As Brazilian rhythms we discuss have originated from dances they all generally require a stable tempo, that's why the first approach in tempo modification and tempo rubato is of special interest for our discussion. It will be covered with examples and video lessons in Advanced section.
In Basics section, while we described rhythmic patterns, we deliberately disregarded rests as parts of rhythmic phrases in order to simplify and reduce number of rhythmic pattern combinations. As our investigation of rhythmic patterns deals with the presence of individual beats in the phrase, we examine only the onset of the note within a phrase, leaving it's duration and ending undefined.
We will now describe different ways of playing the notes in regards to their endings, which is known in music as articulation. In general there are two distinct forms of articulation in regards to note's ending. If a note is ended by muting a string we talk about staccato. When the note is ended by playing the next note without any muting in between this is known as legato.
While the most of bossa nova songs are played with the mix of both styles there are also songs that are played exclusively or at most by one of the styles described. Typically a whole section of the song is performed by one style, however not all notes within a rhythmic phrase are played with the same style. For example whenever there is a chord change it's impossible to play it with legato, so those are played with staccato. At the other hand if there are tied notes during staccato section there is usually some part of the phrase played with legato.
We will classify the phrases as being played by staccato or legato depending on the style used in playing it's main beats.
We defined some important musical terms that are necessary for understanding of complex rhythmic structure that can be found in Brazilian music. We then explained metrical structure of Brazilian music styles and described typical 4 beat rhythmic components that regularly appear in Brazilian rhythms.
We also explained syncopation, usage of different voices and analysed polyrhythmic origin of rhythmic patterns that are used in Brazilian music.
In other sections we will examine popular Brazilian music styles, extract rhythmic phrases that consist of rhythmic patterns discussed here and try to give some hints about using various techniques in order to improve our performance in playing Brazilian music on a guitar.