The term "note" can be used in both generic and specific senses: one might say either "the piece Happy Birthday to You begins with two notes having the same pitch," or "the piece begins with two repetitions of the same note." In the former case, one uses "note" to refer to a specific musical event; in the latter, one uses the term to refer to a class of events sharing the same pitch.
In musical notation, alterations to the seven lettered pitches in the scale are indicated by placing an accidental immediately before the note symbol, or by use of a key signature. The natural symbol can be inserted before a note to cancel a previously indicated flat or sharp (so as "F" an F-sharp would become simply F).
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":
|Sharp (English name)||C sharp||D sharp||F sharp||G sharp||A sharp|
|Flat (English name)||D flat||E flat||G flat||A flat||B flat|
|Natural (Scandinavian after 1990s)||C||D||E||F||G||A||B|
|Sharp (Northern European)||Cis||Dis||Fis||Gis||Ais|
|Flat (Northern European)||Des||Es||Ges||As||Bes|
|Natural (Northern European, and Scandinavian before 1990s)||C||D||E||F||G||A||H|
|Flat (Nothern European, and Scandinavian before 1990s)||Des||Es||Ges||As||B|
|Indian style||Sa||Re Komal||Re||Ga Komal||Ga||Ma||Ma Teevra||Pa||Dha Komal||Dha||Ni Komal||Ni|
|Approx. Frequency [Hz]||262||277||294||311||330||349||370||392||415||440||466||494|
|MIDI note number||60||61||62||63||64||65||66||67||68||69||70||71|
|Octave naming systems||frequency|
of A (Hz)
|subsubcontra||Cˌˌˌ – Bˌˌˌ||C-1 – B-1||0 – 11||13.75|
|sub-contra||Cˌˌ – Bˌˌ||C0 – B0||12 – 23||27.5|
|contra||Cˌ – Bˌ||C1 – B1||24 – 35||55|
|great||C – B||C2 – B2||36 – 47||110|
|small||c – b||C3 – B3||48 – 59||220|
|one-lined||c′ – b′||C4 – B4||60 – 71||440|
|two-lined||c′′ – b′′||C5 – B5||72 – 83||880|
|three-lined||c′′′ – b′′′||C6 – B6||84 – 95||1760|
|four-lined||c′′′′ – b′′′′||C7 – B7||96 – 107||3520|
|five-lined||c′′′′′ – b′′′′′||C8 – B8||108 – 119||7040|
|six-lined||c′′′′′′ – b′′′′′′||C9 – G9||120 – 127||14080|
When notes are written out in a score, each note is assigned a specific vertical position on a staff position (a line or a space) on the staff, as determined by the clef. Each line or space is assigned a note name, these names are memorized by the musician and allows him to know at a glance the proper pitch to play on his instrument for each note-head marked on the page.
The staff above shows the notes C, D, E, F, G, A, B, C and then in reverse order, with no key signature or accidentals.
The note-naming convention specifies a letter, any accidentals (sharps/flats), and an octave number. Any note is an integer of half-steps away from middle A (A4). Let this distance be denoted n. If the note is above A4, then n is positive; if it is below A4, then n is negative. The frequency of the note (f) (assuming equal temperament) is then:
For example, one can find the frequency of C5, the first C above A4. There are 3 half-steps between A4 and C5 (A4 → A4 → B4 → C5), and the note is above A4, so n = +3. The note's frequency is:
To find the frequency of a note below A4, the value of n is negative. For example, the F below A4 is F4. There are 4 half-steps (A4 → A4 → G4 → G4 → F4), and the note is below A4, so n = −4. The note's frequency is:
Finally, it can be seen from this formula that octaves automatically yield factors of two times the original frequency, since n is therefore a multiple of 12 (12k, where k is the number of octaves up or down), and so the formula reduces to:
yielding a factor of 2. In fact, this is the means by which this formula is derived, combined with the notion of equally-spaced intervals.
The distance of an equally tempered semitone is divided into 100 cents. So 1200 cents are equal to one octave — a frequency ratio of 2:1. This means that a cent is precisely equal to the 1200th root of 2, which is approximately 1.0005777895
For use with the MIDI (Musical Instrument Digital Interface) standard, a frequency mapping is defined by:
For notes in an A440 equal temperament, this formula delivers the standard MIDI note number. Any other frequencies fill the space between the whole numbers evenly. This allows MIDI instruments to be tuned very accurately in any microtuning scale, including non-western traditional tunings.
Following this, the system of repeating letters A-G in each octave was introduced, these being written as minuscules for the second octave and double minuscules for the third. When the compass of used notes was extended down by one note, to a G, it was given the Greek G (Γ), gamma. (It is from this that the French word for scale, gamme is derived, and the English word gamut, from "Gamma-Ut", the lowest note in Medieval music notation.)
The remaining five notes of the chromatic scale (the black keys on a piano keyboard) were added gradually; the first being B which was flattened in certain modes to avoid the dissonant tritone interval. This change was not always shown in notation, but when written, B (B-flat) was written as a Latin, round "b", and B (B-natural) a Gothic b. These evolved into the modern flat and natural symbols respectively. The sharp symbol arose from a barred b, called the "cancelled b".
In Italian, Portuguese, Greek, French, Russian, Flemish, Romanian, Spanish, Hebrew and Turkish notation the notes of scales are given also in terms of Do - Re - Mi - Fa - Sol - La - Si rather than C - D - E - F - G - A - B. These names follow the original names reputedly given by Guido d'Arezzo, who had taken them from the first syllables of the first six musical phrases of a Gregorian Chant melody Ut queant laxis, which began on the appropriate scale degrees. These became the basis of the solfege system. "Do" later replaced the original "Ut" for ease of singing (most likely from the beginning of Dominus, Lord), though "Ut" is still used in some places. "Si" or "Ti" was added as the seventh degree (from Sancte Johannes, St. John, to which the hymn is dedicated).