Chapter 2

This is for test.

What is it?

Note name

See also: Key signature names and translations

Names of some notes without accidentals

Two notes with fundamental frequencies in a ratio of any power of two (e.g. half, twice, or four times) are perceived as very similar. Because of that, all notes with these kinds of relations can be grouped under the same pitch class. In traditional music theory pitch classes are represented by the first seven letters of the Latin alphabet (A, B, C, D, E, F and G) (some countries use other names as in the table below). The eighth note, or octave is given the same name as the first, but has double its frequency. The name octave is also used to indicate the span of notes having a frequency ratio of two. To differentiate two notes that have the same pitch class but fall into different octaves, the system of scientific pitch notation combines a letter name with an Arabic numeral designating a specific octave. For example, the now-standard tuning pitch for most Western music, 440 Hz, is named a′ or A4. There are two formal ways to define each note and octave, the Helmholtz system and the Scientific pitch notation.

[edit]Accidentals

Frequency vs Position on Treble Clef. Each note shown has a frequency of the previous note multiplied by 

Letter names are modified by the accidentals. A sharp ♯ raises a note by a semitone or half-step, and a flat ♭ lowers it by the same amount. In modern tuning a half step has a frequency ratio of , approximately 1.059. The accidentals are written after the note name: so, for example, F♯ represents F-sharp, B♭ is B-flat.

Additional accidentals are the double-sharp , raising the frequency by two semitones, and double-flat , lowering it by that amount.

In musical notation, accidentals are placed before the note symbols. Systematic alterations to the seven lettered pitches in the scale can be indicated by placing the symbols in the key signature, which then apply implicitly to all occurrences of corresponding notes. Explicitly noted accidentals can be used to override this effect for the remainder of a bar. A special accidental, the natural symbol ♮, is used to indicate an unmodified pitch. Effects of key signature and local accidentals do not cumulate. If the key signature indicates G-sharp, a local flat before a G makes it G-flat (not G natural), though often this type of rare accidental is expressed as a natural, followed by a flat (♮♭) to make this clear. Likewise (and more commonly), a double sharp  sign on a key signature with a single sharp ♯ indicates only a double sharp, not a triple sharp.

Assuming enharmonicity, many accidentals will create equivalences between pitches that are written differently. For instance, raising the note B to B♯ is equal to the note C. Assuming all such equivalences, the complete chromatic scale adds five additional pitch classes to the original seven lettered notes for a total of 12 (the 13th note completing the octave), each separated by a half-step.

Notes that belong to the diatonic scale relevant in the context are sometimes called diatonic notes; notes that do not meet that criterion are then sometimes called chromatic notes.

Another style of notation, rarely used in English, uses the suffix "is" to indicate a sharp and "es" (only "s" after A and E) for a flat, e.g. Fis for F♯, Ges for G♭, Es for E♭. This system first arose in Germany and is used in almost all European countries whose main language is not English or a Romance language.

In most countries using this system, the letter H is used to represent what is B natural in English, the letter B represents the B♭, and Heses represents the B♭♭ (not Bes, which would also have fit into the system). Belgium and the Netherlands use the same suffixes, but applied throughout to the notes A to G, so that B♭ is Bes. Denmark also uses H, but uses bes instead of heses for B♭♭.

This is a complete chart of a chromatic scale built on the note C4, or "middle C":