Diatonic and chromatic in the context of "Accidentals"

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.

Chromaticism is a compositional technique interspersing the primary diatonic pitches and chords with other pitches of the chromatic scale. In simple terms, within each octave, diatonic music uses only seven different notes, rather than the twelve available on a standard piano keyboard. Music is chromatic when it uses more than just these seven notes.

Chromaticism is in contrast or addition to tonality or diatonicism and modality (the major and minor, or "white key", scales). Chromatic elements are considered, "elaborations of or substitutions for diatonic scale members".

The harmonica, also known as a French harp or mouth organ, is a free reed wind instrument used worldwide in many musical genres, notably in blues, American folk music, classical music, jazz, country, and rock. The many types of harmonica include diatonic, chromatic, tremolo, octave, orchestral, and bass versions. The harmonica is played by using the lips and tongue to direct air into or out of one (or more) holes along a mouthpiece (which covers one edge of the harmonica for most of its length). Behind each hole is a chamber containing at least one reed. The most common type of harmonica is a diatonic Richter-tuned instrument with ten air passages and twenty reeds, often called a blues harp. The harmonica reed is a flat, elongated spring typically made of brass, stainless steel, or bronze, which is secured at one end over a slot that serves as an airway. When the free end is made to vibrate by the player's air, the reed alternately blocks and unblocks the airway to produce sound.

Reeds are tuned to individual pitches. Tuning may involve changing a reed's length, how heavy it is near its free end, or how stiff it is near its fixed end. Reeds that are longer, heavier, or more flexible produce lower pitches; shorter, lighter, or stiffer reeds produce higher pitches. If, as on most modern harmonicas, a reed is affixed above or below its slot rather than in the plane of the slot, it responds more easily to air flowing in the direction that initially would push it into the slot, i.e., as a closing reed. This difference in response to air direction makes it possible to include both a blow reed and a draw reed in the same air chamber, and to play them separately without relying on flaps of plastic or leather (valves, wind-savers) to block the nonplaying reed.

In music, extended chords are certain chords (built from thirds) or triads with notes extended, or added, beyond the seventh. Ninth, eleventh, and thirteenth chords are extended chords. The thirteenth is the farthest extension diatonically possible as, by that point, all seven tonal degrees are represented within the chord (the next extension, the fifteenth, is the same as the root of the chord). In practice however, extended chords do not typically use all the chord members; when it is not altered, the fifth is often omitted, as are notes between the seventh and the highest note (i.e., the ninth is often omitted in an eleventh chord; the ninth and eleventh are usually omitted in a thirteenth chord), unless they are altered to give a special texture.

Chords extended beyond the seventh are rarely seen in the Baroque era, and are used more frequently in the Classical era. The Romantic era saw greatly increased use of extended harmony. Extended harmony prior to the 20th century usually has dominant function – as V, V, and V, or V/V, V/ii etc.

Alessandro Rolla (Italian pronunciation: [alesˈsandro ˈrɔlla]; 23 April 1757 – 14 September 1841) was an Italian viola and violin virtuoso, composer, conductor and teacher. His son, Antonio Rolla, was also a violin virtuoso and composer.

His fame now rests mainly as "teacher of the great Paganini", yet his role was very important in the development of violin and viola technique. Some of the technical innovations that Paganini later utilized largely, such as left-hand pizzicato, chromatic ascending and descending scales, the use of very high positions on violin and viola, octave passages, were first introduced by Rolla.