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CAPÍTULO 4 -- O TECLADO DO PIANO E A HARMONIA BÁSICA |
If you've taken a look at a standard piano, organ, or synthesizer keyboard, you probably noticed a pattern of white and black keys. The accompanying illustration shows that there is a pattern of two black keys, then three black keys, then two, three, etc. Ignoring the black keys for a few moments (they DO function as notes and are more than just spacers), if you count the white keys, you will find that you have only seven of them before the pattern repeats.
In the previous chapter you have seen another item that also has seven elements. The musical alphabet has only seven pitches before it also begins repeating. You may have already guessed that the pattern of the keys on a keyboard go hand in hand with this pattern.
On the keyboard, going from left to right goes UP on the staff (all clefs), goes UP in pitch, and FORWARD in the alphabetical sequence
On the keyboard, going from right to left goes DOWN on the staff (all clefs), goes DOWN in pitch, and BACKWARD in the alphabetical sequence.
Instead of starting the pattern with the note A, as would seem logical, we will start with C. Find the group of two black keys; the white key between the set of two is the note "D" and immediately to the left of it is the note C. The white key to the right of C is D, then E, then F, G, A, B, and the next C occurs at exactly the same point in the next cycle of keys (you C one, you've C'd them all). This pattern never changes or reverses itself. The note C that is the closest to the center of the piano (often the trademark of its manufacturer) is called "middle C" and happens to be the note on the ledger line that falls immediately between the treble and the bass clefs.
The white keys are the only keys with unaltered letter names, also called "naturals". Black keys are named for their position relative to the white keys.
Once you've established the names of the white keys, the black keys are simple to name. Look at the keyboard diagram again and you can see that each is physically placed between two white keys. The pitch is exactly as it appears it would be--between the two adjacent white keys. Imagine a musician's nightmare of sitting down to a keyboard that has no black keys--there would be no reference points for him to look at!
In the section on pitch and notation, you encountered the terms "sharp" and "flat". When a player plays a sharped note (not "sharpened", but "sharped"), that means that he will go up to the very next note higher in pitch. It is unimportant if the next note is a white key or a black key, the musician just follows orders. The next highest note above a C is a C#, called "C Sharp", not "Sharp C".
When a player plays a flatted note (not flattened!), it means the opposite--to play the next lowest note, be it black or white. The note immediately below an E is an Eb, called an "E Flat", not a "Flat E". The colors black and white in this description refer to the keys on a piano, which is the easiest to see and visualize. A singer or non keyboard player usually doesn't think in the terms of note colors, but will still use sharps and flats.
You can probably gather from that this that each black key will then have two names--a sharp name and a flat name. On the keyboard, for example, a D# is the same as an Eb. Another name for a B# is a C.
In reality, the system is a little less confusing--and much more logical--than it may initially sound.
Why would this happen, anyway?
Two reasons--first, less than three centuries ago, the notes D# and Eb were not quite the same. As played by a 17th century musician, they would be a few hundredths of a tone apart from each other. J. S. Bach is given credit for steering things in the present direction. The tradition of having the two names available continued, mostly for the second reason, which is that musical notation is written with a lot of patterns. So much so, that in fact there is a fair similarity between the composition of a piece of music and the writing of many computer programs.
Again, the rules here are quite complex, and a beginning text isn't the place to dip into intermediate music theory, but the following is a simple explanation: When a musician sits down to play a piece of music, he instinctively begins looking for patterns which will make reading a very complicated framework a bit easier and a lot faster.
When a piece of music starts out using flats, it generally will continue using flats. Musicians are trained to expect this. Ditto for sharps--when a composition starts out using sharps, a musician instinctively expects to see sharps. Throwing a note at a musician that is out of context can cause confusion. Even though they contain the same notes, a chord containing the notes F#, A#, C#, E# will be understood and read a lot quicker than one spelled Gb, A#, Db, F. In pieces of music that have thousands of notes go by in a very rapid fashion, being able to digest and react quickly is vital for any musician.
While there is no need to dwell on the difference between a whole step and a half step, it is necessary to understand some of the differences in harmony.
Very simply, a half step is the smallest interval that can be played on a keyboard. A half step is two keys immediately adjacent to each other. In other words, there is no other key between them. The notes E and F, as well as B and C are one half step apart from each other. C and C# are one half step apart. There are no instances where two black keys are one half step from each other.
It shouldn't be too much of a surprise to learn that a whole step is two half steps put together. In other words, an interval of a whole step consists of two keys with one note between them. Some examples of whole step intervals are from the notes C to D, F to G, E to F#, Ab to Bb.
Take a look at the pattern of white keys from one C to another. It contains places where some keys are immediately adjacent to each other (E,F and B,C--half steps) and others which are separated by a black key (whole steps). This pattern is one of the few in music which is asymmetrical, but it is nevertheless an important one. This pattern of alternate and consecutive notes is called a MAJOR SCALE (scale coming from the same root as the Italian word meaning 'ladder'). This pattern is a germinal basis for a huge percentage of Western music in terms of both the melody and the harmony.
To create a major scale on any note of the keyboard, you need only to duplicate the pattern of whole and half steps. A half step is needed between the 3rd and 4th, and the 7th and 8th notes. All other intervals in the scale are whole steps. Starting on C is the only time you won't need any black keys.
When a piece of music is said to be "in the key of C", that means its melody is based on the tones found in the C major scale. The harmonies are built around combinations of those same notes. The other notes can be (and usually are) used, but those notes hold the primary importance in traditional harmony. A composition in the key of Bb means that its melody and harmony are based around the notes outlined in the Bb major scale.
It might sound as if a musician has a formidable task ahead of him, but in reality there are only twelve different pitches, giving only twelve different major scales to learn, and many learn them quickly. In addition, many scales are closely related to each other.
Next, look at the pattern from A to A. The alternate and consecutive pattern is a little different from the C to C example. The half steps fall between the second and third notes and the fifth and the sixth notes of this scale. If you start on another note, these whole/half step patterns must be duplicated EXACTLY to produce what is called a minor scale. Like the major scale, the minor scale is used extensively to create the building blocks of harmonies and melodies. A piece of music "in the key of C# minor" means that its melody is based on notes found in the C# minor scale and its harmony is based on combinations of notes found in the same. Like the major scale, there are only twelve different versions of the "natural minor scale".
Are other patterns used in compositions? Yes, but not nearly as often. Sometimes a "whole tone scale" is used, being made entirely of intervals of whole steps.
Other patterns patterns were used in the Middle Ages and called "modes" instead of scales. The pattern beginning on C was called "Ionian". Going up from there you have "Dorian", "Phrygian", "Lydian", "Mixolydian", "Aeolian" (the minor scale), and "Locrian". Compositions using combinations other than the Ionian (major) or Aeolian (minor) tend to sound very foreign to our ears and much less satisfying, although, surprisingly, a number of these modes pop up in heavy metal.
Without going too far into harmony, some very basic three note chords (called triads) can be built using whole and half steps.
Playing any note on the keyboard (the root of your chord), if you go up two whole steps and play that note, then go up one and a half steps, you will have created a major triad. Below are two examples of this.
If you reverse the two intervals and have an interval of one and a half steps from the first to the second note of the chord, and have two steps between the second and third of the chord, you will have a minor triad.
A "diminished chord" consists of two one and a half step intervals, which an "augmented chord" is made up of an two two-step intervals. Played by themselves, neither of these sounds as pleasing as a major or minor triad by itself.