Tuesday, 19 February 2013

Jazz



In jazz and jazz harmony, the term altered chord, notated as an alt chord (e.g. G7alt  Play (help·info)), refers to a dominant chord, "in which neither the fifth nor the ninth appears unaltered".[3] – namely, where the 5th and the 9th are raised or lowered by a single semitone, or omitted. Altered chords are thus constructed using the following notes, some of which may be omitted:

root
3
5 and/or 5
7
9 and/or 9

Altered chords may include both a flatted and sharped form of the altered fifth or ninth, e.g. G7559; however, it is more common to use only one such alteration per tone, e.g. G759, G759, G759, or G759.

The choice of inversion, or the omission of certain tones within the chord (e.g. omitting the root, common in guitar harmony), can lead to many different possible colorings, substitutions, and enharmonic equivalents. Altered chords are ambiguous harmonically, and may play a variety of roles, depending on such factors as voicing, modulation, and voice leading.

The altered chord's harmony is built off the altered scale, which includes all the alterations shown in the chord elements above:

root
9 (=2)
9 (=2 or 3)
3
11 (=4 or 5)
13 (=5)
7

Altered chords can be analyzed as a kind of tritone substitution (5 substitution). Thus the alt chord on a given root is the same as the 711 chord on the root a tritone away (e.g., G7alt is the same as D711 Play (help·info)).

Altered chords are commonly substituted for regular dominant V chords in ii-V-I progressions, most commonly in minor harmony leading to an i7 (tonic minor 7th) chord.

More generally in jazz, the terms altered chord and altered tone also refer to the family of chords that involve 9 and 5 voicing, as well as to certain other chords with related ambiguous harmony. Thus the "79 chord" (e.g. G79) is used in the context of a dominant resolution to a major tonic, which is typically voiced with a 13 rather than the 13 of the alt chord. When voiced with a 13, jazz musicians typically play the half-step/whole-step diminished scale over the 9 chord (e.g. G, A, B, B, C, D, E, F over G79).

Note that in chord substitution and comping, a 79 is often used to replace a diminished chord, for which it may be the more "correct" substitution due to its incorporation of an appropriate root tone. Thus, in a progression where a diminished chord is written in place of a G7 chord, i.e. where the dominant chord is replaced by an A-dim (A-C-E = G-B-D), D-dim (D-F-A), B-dim (B-D-F), or F-dim (F-A-C = F-G-B)), a G79 is often played instead. G79 (G-B-D-F-A) contains the same notes as any of these diminished chords with an added G root.

Monday, 6 August 2012

Altered

Altered may refer to:
An Altered, a type of drag racing car
Altered, a 2006 film
Alterim, is the contrasting element of Interim.

Thursday, 18 August 2011

Alstonia


Alstonia (devil tree) consists of about 40-60 species (according to different authors), native to tropical and subtropical Africa, Central America, southeast Asia, Polynesia and Australia, with most species in the Malesian region.

These trees can grow very large, such as Alstonia pneumatophora, recorded with a height of 60 m and a diameter of more than 2 m. Alstonia longifolia is the only species growing in Central America (mainly shrubs, but also trees 20 m high).

The leathery, sessile, simple leaves are elliptical, ovate, linear or lanceolate and wedge-shaped at the base. The leaf blade is dorsiventral, medium-sized to large and disposed oppositely or in a whorl and with entire margin. The leaf venation is pinnate, with numerous veins ending in a marginal vein.


Alstonia scholaris in Hyderabad, India.

The inflorescence is terminal or axillary, consisting of thyrsiform cymes or compound umbels. The small, more or less fragrant flowers are white, yellow, pink or green and funnel-shaped, growing on a pedicel and subtended by bracts. They consist of 5 petals and 5 sepals, arranged in four whorls.

The fertile flowers are hermaphrodite. The gamosepalous green sepals consist of ovate lobes, and are distributed in one whorl. The annular disk is hypogynous. The five gamesepalous petals have oblong or ovate lobes and are disposed in one whorl. The corolla lobes overlapping to the left (such as A. rostrata) or to the right (such as A. macrophylla) in the bud. The ovary has 2 separate follicles with glabrous or ciliate, oblong seeds that develop into deep blue podlike, schizocarp fruit, between 7-40 cm long. The plants contain a milky sap, rich in poisonous alkaloids. The Alstonia macrophylla is commonly known in Sri Lanka as 'Havari nuga' or the 'wig banyan' because of its distinct flower that looks like a woman's long wig.

Alstonia trees are used in traditional medicine. The bark of the Alstonia constricta and the Alstonia scholaris is a source of a remedy against malaria, toothache, rheumatism and snake bites[citation needed]. The latex is used in treating coughs, throat sores and fever.

Many Alstonia species are commercial timbers, called pule or pulai in Indonesia and Malaysia. Trees from the section Alstonia produce light timber, while those from the sections Monuraspermum and Dissuraspermum produce heavy timber.

Alstonia trees are widespread and mostly not endangered. However a few species are very rare, such as A. annamensis, A. beatricis, A. breviloba, A. stenophylla and A. guangxiensis.