TToW #7: Spectral centroid

Spectral centroid is an acoustical descriptor of timbre. Its value is obtained through a statistical measurement on the frequency representation of the signal (the frequency spectrum - see Timbre Term of the Week "Signal vs Spectrum"). As its name says, centroid is a spectral descriptor and corresponds to a specific type of estimation of the spectral shape (or curve)…

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Amazing Moments in Timbre #6

Trevor Wishart is a contemporary British composer closely associated with extended uses of the human voice. Whether in acousmatic pieces such as Encounters in the Republic of Heaven (2011) or in pieces for live performance such as Vox 4 (1987), his compositions masterfully exploit the subtlety and range of human vocal production…

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TToW #6 : Signal vs. Spectrum

Dans la vie de tous les jours, les sons sont captés par notre appareil auditif et analysés par notre cerveau. Cependant, afin de mieux comprendre les phénomènes physiques découlant du son, on a recours à des méthodes d'analyse analogiques et computationnelles, qui utilisent différents types de représentation de la vibration sonore…

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Amazing Moments in Timbre #4

The Amazing Moments in Timbre series continue with a piece by Olga Neuwirth. Known as the "Enfant terrible" of the Austrian contemporary classical music scene, Neuwirth composes in a very theatrical and expressionist way, and describes her own art as a music of catastrophes ("Katastrophenmusik"). In her Hommage à Klaus Nomi (2009), for countertenor and chamber ensemble…

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TToW #5 : Shepard Tone

Timbre Term of the Week #5 : Shepard Tone

 In post #4 about Auditory Scene Analysis, we introduced some of the ways that sound components are grouped together by the auditory system. This has many musical applications, and also lays the foundation for some interesting auditory illusions. One of the most famous is the Shepard Tone, named for cognitive scientist Roger Shepard, which creates an illusion of perpetual ascent or descent. A quick search on YouTube will turn up many examples; here is a handful:

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TToW #4 : Auditory Scene Analysis

This is a spectrograph, a way of visualizing sound in which the y axis represents frequency, the x axis represents time, and darkness or colour represents concentration of energy. Looking from bottom to top shows how the sound energy is distributed on the continuum from low to high, and looking from left to right shows how that distribution changes over time...

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TToW #3 : Envelope

In synthesis and sound recording and mixing, envelope describes how a sound’s amplitude (volume) changes over time.  When recreating the timbre of an instrument (or other sounds such as a firetruck siren), it is equally important to get the overtone series right as it is to reconstruct or preserve the contour of the sound….

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TToW #1 : Partial

Although we may perceive sounds such as musical notes as singular, self-contained units, the physical reality often suggests something very different.  Most sounds we hear are actually complex mixtures of many different sound components, some of which are noisy and transient, others of which may have stable frequencies…

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