Pitch class in the context of "Octave"

In music, notes are distinct and isolatable sounds that act as the most basic building blocks for nearly all of music. This discretization facilitates performance, comprehension, and analysis. Notes may be visually communicated by writing them in musical notation.

Notes can distinguish the general pitch class or the specific pitch played by a pitched instrument. Although this article focuses on pitch, notes for unpitched percussion instruments distinguish between different percussion instruments (and/or different manners to sound them) instead of pitch. Note value expresses the relative duration of the note in time. Dynamics for a note indicate how loud to play them. Articulations may further indicate how performers should shape the attack and decay of the note and express fluctuations in a note's timbre and pitch. Notes may even distinguish the use of different extended techniques by using special symbols.

The twelve-tone technique—also known as dodecaphony, twelve-tone serialism, and (in British usage) twelve-note composition—is a method of musical composition. The technique is a means of ensuring that all 12 notes of the chromatic scale are sounded equally often in a piece of music while preventing the emphasis of any one note through the use of tone rows, orderings of the 12 pitch classes. All 12 notes are thus given more or less equal importance, and the music avoids being in a key.

The technique was first devised by Austrian composer Josef Matthias Hauer, who published his "law of the twelve tones" in 1919. In 1923, Arnold Schoenberg (1874–1951) developed his own, better-known version of 12-tone technique, which became associated with the "Second Viennese School" composers, who were the primary users of the technique in the first decades of its existence. Over time, the technique increased greatly in popularity and eventually became widely influential on mid-20th-century composers. Many important composers who had originally not subscribed to or actively opposed the technique, such as Aaron Copland and Igor Stravinsky, eventually adopted it in their music.

The chromatic scale (or twelve-tone scale) is a set of twelve pitches (more completely, pitch classes) used in tonal music, with notes separated by the interval of a semitone. Chromatic instruments, such as the piano, are made to produce the chromatic scale, while other instruments capable of continuously variable pitch, such as the trombone and violin, can also produce microtones, or notes between those available on a piano.

Most music uses subsets of the chromatic scale such as diatonic scales. While the chromatic scale is fundamental in western music theory, it is seldom directly used in its entirety in musical compositions or improvisation.

In music theory, a major chord is a chord that has a root, a major third, and a perfect fifth. When a chord comprises only these three notes, it is called a major triad. For example, the major triad built on C, called a C major triad, has pitches C–E–G:

In harmonic analysis and on lead sheets, a C major chord can be notated as C, CM, CΔ, or Cmaj. A major triad is represented by the integer notation {0, 4, 7}.

A register is the range within pitch space of some music or often musical speech. It may describe a given pitch or pitch class (or set of them), a human voice or musical instrument (or group of them), or both, as in a melody or part. It is also often related to timbre and musical form. In musical compositions, it may be fixed or "frozen".

In music, a common tone is a pitch class that is a member of, or common to (shared by) two or more chords or sets. Typically, it refers to a note shared between two chords in a chord progression. According to H.E. Woodruff:

The example below shows the seven diatonic triads of C major. The common tones between the tonic triad and the other six triads are highlighted in blue. As Woodruff describes, the tonic triad shares no common tones with either II and VII (consecutive to I), one common tone with IV and V (four and five degrees from I) each, and two common tones with III and VI (three and six degrees from I) each.

A set (pitch set, pitch-class set, set class, set form, set genus, pitch collection) in music theory, as in mathematics and general parlance, is a collection of objects. In musical contexts the term is traditionally applied most often to collections of pitches or pitch-classes, but theorists have extended its use to other types of musical entities, so that one may speak of sets of durations or timbres, for example.

A set by itself does not necessarily possess any additional structure, such as an ordering or permutation. Nevertheless, it is often musically important to consider sets that are equipped with an order relation (called segments); in such contexts, bare sets are often referred to as "unordered", for the sake of emphasis.