In music, a glissando is a glide from one pitch to another. It is an Italianized musical term derived from the French glisser, "to glide". In some contexts, it is distinguished from the continuous portamento. Some colloquial equivalents are slide, sweep, bend, smear, rip, lip, plop, or falling hail.
Perception is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information, or the environment.
A strange loop is a cyclic structure that goes through several levels in a hierarchical system. It arises when, by moving only upwards or downwards through the system, one finds oneself back where one started.
An optical illusion is an illusion caused by the visual system and characterized by a visual percept that arguably appears to differ from reality. Illusions come in a wide variety; their categorization is difficult because the underlying cause is often not clear but a classification proposed by Richard Gregory is useful as an orientation. According to that, there are three main classes: physical, physiological, and cognitive illusions, and in each class there are four kinds: Ambiguities, distortions, paradoxes, and fictions. A classical example for a physical distortion would be the apparent bending of a stick half immerged in water; an example for a physiological paradox is the motion aftereffect. An example for a physiological fiction is an afterimage. Three typical cognitive distortions are the Ponzo, Poggendorff, and Müller-Lyer illusion. Physical illusions are caused by the physical environment, e.g. by the optical properties of water. Physiological illusions arise in the eye or the visual pathway, e.g. from the effects of excessive stimulation of a specific receptor type. Cognitive visual illusions are the result of unconscious inferences and are perhaps those most widely known.
A Shepard tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. When played with the bass pitch of the tone moving upward or downward, it is referred to as the Shepard scale. This creates the auditory illusion of a tone that continually ascends or descends in pitch, yet which ultimately seems to get no higher or lower.
Gestalt psychology or gestaltism is a school of psychology that emerged in Austria and Germany in the early twentieth century based on work by Max Wertheimer, Wolfgang Köhler, and Kurt Koffka. As used in Gestalt psychology, the German word gestalt is interpreted as "pattern" or "configuration". Gestalt psychologists emphasized that organisms perceive entire patterns or configurations, not merely individual components. The view is sometimes summarized using the slogan, "the whole is more than the sum of its parts."
Pitch is a perceptual property of sounds that allows their ordering on a frequency-related scale, or more commonly, pitch is the quality that makes it possible to judge sounds as "higher" and "lower" in the sense associated with musical melodies. Pitch can be determined only in sounds that have a frequency that is clear and stable enough to distinguish from noise. Pitch is a major auditory attribute of musical tones, along with duration, loudness, and timbre.
Piano Phase is a minimalist composition by American composer Steve Reich, written in 1967 for two pianos. It is one of his first attempts at applying his "phasing" technique, which he had previously used in the tape pieces It's Gonna Rain (1965) and Come Out (1966), to live performance.
Auditory illusion are false perceptions of a real sound/outside stimulus. These false perceptions are the equivalent of an optical illusion: the listener hears either sounds which are not present in the stimulus, or sounds that should not be possible given the circumstance on how they were created. Auditory illusions highlight areas where the human ear and brain, as organic survival tools, differentiate from perfect audio receptors; this shows that it is possible for a human being to hear something that is not there and be able to react to the sound they supposedly heard.
Benjamin Burwell Johnston Jr. was an American contemporary music composer using just intonation. He was called "one of the foremost composers of microtonal music" by Philip Bush (1997) and "one of the best non-famous composers this country has to offer" by John Rockwell (1990).
James Tenney was an American composer and music theorist. He made significant early musical contributions to plunderphonics, sound synthesis, algorithmic composition, process music, spectral music, microtonal music, and tuning systems including extended just intonation. His theoretical writings variously concern musical form, texture, timbre, consonance and dissonance, and harmonic perception.
Rudolf Arnheim was a German-born author, art and film theorist, and perceptual psychologist. He learned Gestalt psychology from studying under Max Wertheimer and Wolfgang Köhler at the University of Berlin and applied it to art. His magnum opus was his book Art and Visual Perception: A Psychology of the Creative Eye (1954). Other major books by Arnheim have included Visual Thinking (1969), and The Power of the Center: A Study of Composition in the Visual Arts (1982). Art and Visual Perception was revised, enlarged and published as a new version in 1974, and it has been translated into fourteen languages. He lived in Germany, Italy, England, and America where he taught at Sarah Lawrence College, Harvard University, and the University of Michigan. He has greatly influenced art history and psychology in America.
Density 21.5 is a piece of music for solo flute written by Edgard Varèse in 1936 and revised in 1946. The piece was composed at the request of Georges Barrère for the premiere of his platinum flute the density of platinum being close to 21.5 grams per cubic centimetre.
Figure–ground organization is a type of perceptual grouping which is a vital necessity for recognizing objects through vision. In Gestalt psychology it is known as identifying a figure from the background. For example, words on a printed paper are seen as the "figure" and the white sheet as the "background".
In audio engineering, a fade is a gradual increase or decrease in the level of an audio signal. The term can also be used for film cinematography or theatre lighting in much the same way.
The spectral approach to musical composition was first given a name in 1979 by Hugues Dufourt in an article he entitled, "Musique spectrale" [Spectral Music]. In spectral music, the spectrum – or group of spectra – replace harmony, melody, rhythm, orchestration and form. The spectrum is always in motion, and the composition is based on spectra developing through time and exerting an influence on rhythm and formal processes. Spectral music seeks to exteriorize the inner reality of sound, to project its inner dynamics into an acoustic space and time, and to transmit to the public the reality of sound in all its complexity.
Roger Newland Shepard is an American cognitive scientist and author of the "universal law of generalization" (1987). He is considered a father of research on spatial relations. He studied mental rotation, and was an inventor of non-metric multidimensional scaling, a method for representing certain kinds of statistical data in a graphical form that can be apprehended by humans. The optical illusion called Shepard tables and the auditory illusion called Shepard tones are named for him.
Marc Sabat is a Canadian composer based in Berlin since 1999.
A constant timbre at a constant pitch is characterized by a spectrum. Along a piece of music, the spectrum measured within a narrow time window varies with the melody and the possible effects of instruments. Therefore, it may seem paradoxical that a constant spectrum can be perceived as a melody rather than a stamp.
Litanei 97 is a choral work by German composer Karlheinz Stockhausen, written in 1997. Although the words are taken from the text-composition cycle Aus den sieben Tagen and the conductor sings and plays elements from the Michael formula used in the composer's Licht cycle of operas, it is an independent work assigned the number 74 in Stockhausen's catalogue of works. It lasts about twenty minutes in performance.