In music, the word alteration can mean three things.
- Tampering refers first to the modification of the initial height of a note, in other words, this note is to make more serious or more acute, and that, whatever the reasons for this change: modulation , transposition, ornamentation ...
- Then, on the partition, and more specifically on the scope, means an alteration in charge of the symbol indicate the change. Especially this second sense that catch our attention in this article.
- Finally, and by extension, it is also possible to consider an alteration represents the new notes as amended, ie, the "impairment rating assigned."
As a figure showing the change in the original height of a note, the alteration is placed on the scope, precisely on the line or the spacing of the note it affects, and left.
Different figures of alterations
We distinguish between simple alterations and alterations double, the first being the most common.
They are threefold: the sharp, the flat and natural.
- The sharp ( ) Is the alteration which raises the note one semitone chromatic .
- The flat ( is the change which lowers the note one semitone chromatic.
- The natural ( ) cancels the effect of all previous changes (whether single or double component or accidental) and makes a note to its natural height.
- The word sharp or diese comes from the Greek diesis that, at the time of ancient Greece, had roughly the same direction. The origin of the words flat and B-natural origins in medieval times, and refer to the note B, which was the first to be affected in a flat in certain circumstances. Thus, etymologically means B-flat soft - that is to say, B rounded, designating the current B-flat - and natural, B square (pointing to his lap B natural).
There are two alterations double in modern solfeggio, double sharp and double flat.
- The double sharp is the alteration which raises the note by two chromatic semitones.
- The double flat is the alteration that lowers the note by two chromatic semitones.
For the sake of completeness, mention that there also existed other three alterations double now fallen into disuse because they contain the original B-natural is seen as redundant: double natural, the natural-sharp and natural-flat.
- Double natural alteration was that made its original height to a note doubly sharpened or doubly flattened - that is to say, assigned a double sharp or double flat. Today, by definition, a natural sign is enough.
- The natural-sharp was altered to change a note doubly sharpened to a note just sharpened. Today, a sharp is enough.
- The natural-flat was alteration which changed a note doubly flattened in a note simply flattened. Today, a flat one will do.
Effect of alterations
The effect of alteration is different depending on whether it is in the piece - accidental alteration - or to the key - constitutive alteration.
- It should be noted that an altered note is named before the alteration, but is noted below. For example, a C will be assigned a hash called "C sharp", but, on the score, the sharp will be written before the C - "C sharp", in short - This is to avoid playing in error a C to realize that it was actually a C-sharp that have been playing.
An accidental alteration - referred to simply crash - intervenes in the course of the song, and concerns all the notes of the same name and same height that come after it to the same extent. The effect of accidental alteration is temporary and supersedes any previous alteration affecting the note.
- Eg :
- In the example above, the first sharp accidentally assigned grades 2 and 4, the second sharp accidental affects footnote 6, the third sharp accidental affects footnote 8 and B-natural accidental affects Note No.5.
- We can therefore consider that the bar cancels the effect of all the accidents that have preceded it.
- Some composers however, probably thinking that "two better safe than sorry" add to after the bar line and before the note in question, alteration restoring the original height of a given note had been changed accidentally during a previous measure. Such accidental alteration, which is not really necessary, is then called "alteration of caution", precisely.
- This rule has a small exception. When two notes of the same height and assigned the same accident, are united by a tie, and a bar line passes between the two notes in question, we do not write the change to the second note. If the same note is written in the second measure, it remains altered until the next bar (unless otherwise noted). Eg :
Alteration constitutive is valid throughout the range, for all notes of the same name - same height different this time - except of course if an accident occurs in the meantime changing the height of the note.
- Eg :
- In the example above, the E (Flat Constitution) affects all the notes except notes No.4 and No.6 because of accidental naturals.
- Placed at the beginning of the scope, just after the key changes the component form what is called an armature, or armor.
While in modern notation, the sign of tampering expresses an absolute height in the musical system, until the XVIIIth century it had value only relative: the most common case, in early music is that of pieces with a flat in the key (the B ), in which a sharp before B designate a B natural - and not B sharp, that makes little sense at this time!
It should be noted also that in these old scores, accidental alteration is generally valid for the note it precedes, and not the entire measure.
An intermediate grade, in every tone of the scale diatonic base, a sound added by an alteration which divides it into two half-tone colors: that is the diatonic scale is chromatic scale, as can be defined as "the diatonic scale magnified by the intermediate notes":
Note that unlike the diatonic scale, which contains only tones and semitones diatonic and chromatic scale is made up exclusively of half-tones - chromatic semitones, but also diatonic semitones.
- Example, in the octave of C/C
With the development of microtonal music - and, in particular, in quarter-tones - new forms of alterations have been created. However, there is no universally accepted standard.
The quarter-tones are sometimes simply indicated by arrows (up or down), compared to the conventional weathering half-tones. The following chart shows the types of alterations quarter-tone that seem most prevalent today.Alterations in the quarter-tones
But if those corresponding to half-sharp and sharp-and-half seems well accepted, we find, among composers, a greater variety of forms to write the half-flat and flat-and-half.
- The flat crossed
♭is the half-flat, used to lower the note a quarter tone.
This form of half-flat seems to be established by usage, since the XXth century, in the notation of maqâmat Arab music.
- The sharp crossed
♯is the semi-sharp, used to raise the note one quarter tone.
Other alterations microtonal
There are multiple systems of microtonal alterations :
- Ohana simply note the change of third-of-tone bottom with " / " before the note, two-thirds-of-tone with " // ".
- In a context of pure intonation, " / " and " // " but also " " and " " may indicate an alteration of one or two (etc...) comma(s) syntonic(s) up or down (relative to a repository Pythagorean).
- From its alterations quarter-tonal Wyschnegradky design a coherent system of alterations to the 12th tone (by adding to each " / " or " // " to raise one or two twelfth(s) tone.
- The same scale (equal temperament dividing the octave into 72) has recently seen bloom notation "sagittal".
- Ligeti notes the harmonics of natural horns, by alterations arrow (indicating, in approximate distance of the note with equal temperament).
Last update : 05/04/2009 00:00
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