Image:DescenteInfinie.ogg

From Wikipedia, the free encyclopedia

You have new messages (last change).

DescenteInfinie.ogg‎ File size: 336 KB, MIME type: application/ogg

Wikimedia Commons logo This is a file from the Wikimedia Commons. The description on its description page there is shown below.
Commons is attempting to create a freely licensed media file repository. You can help.
Featured sound star This is a featured sound file, which means that members of the community have identified it as one of the finest sound files on the English Wikipedia, adding significantly to its accompanying article. If you have a different recording of similar quality, be sure to upload it using the proper free license tag, add it to a relevant article, and nominate it.

Contents

[edit] Summary

[edit] Comments

  • English : This is a Shepard-Risset glissando. I programmed this acoustic illusion in Java one year ago. Unfortunately, the source code is lost today because of a computer crash, but the equation is below.
  • Français : Ceci est un glissando de Shepard-Risset. J'ai programmé cette illusion acoustique en Java il y a un an. Le code source est malheureusement perdu (crash de mon ordinateur), mais l'équation est présentée ci-dessous.

[edit] Equation

\,s T-periodic on \mathbb{R}

\forall t \in \left [0, T \right [

\,s(t) = a(t) * \sin \left ( \omega(t) t \right ) + a(t + T) \sin \left (2 \omega(t) t \right )

with \begin{cases} \begin{array}{lcl} a(t) & = & A_0 \cfrac{1 + \cos \pi \frac{t}{T}}{4} \\ \omega(t) & = & 2 \pi F_0 \cfrac{1}{2^\frac{t}{T}} \\ F_0 & = & 220\,Hz \\ T & = & 20\,s \\ A_0 & = & 0.7 \end{array} \end{cases}

The same signal is added on a minor chord, on several octaves, see details on my web site.

--Gloumouth1 01:39, 10 December 2005 (UTC)

[edit] Loop

If you want to have a loop, as T = 20 s, you can crop this sound exactly from 20 s to 40 s.

[edit] Another idea

If I (or you) have time, one day, another function witch could be programmed and recorded...

\forall t \in \mathbb{R} \quad s (t) = \sum_{k=-\infty}^\infty a_k(t) \sin \left ( \omega_k(t) t \right )

with \begin{cases} a_k(t) = A_0 e^{-\cfrac{ \left ( k-\frac{t}{T} \right ) ^2}{\sigma^2}} \\ \omega_k(t) = 2 \pi F_0 2^{k - \frac{t}{T}} \\ A_0, F_0, T, \sigma \, constants \end{cases}

--Gloumouth1 17:04, 5 March 2007 (UTC)

[edit] Licensing

This illustration was made by Gloumouth1.

Please credit this : Gloumouth1, http://gloumouth1.free.fr

An email to gloumouth1 at laposte.net would be appreciated too.
I, the author of this work, hereby publish it under the following licenses:
GNU head Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

العربية | Asturianu | Български | বাংলা | ইমার ঠার | Brezhoneg | Bosanski | Català | Sinugboanong Binisaya | Česky | Dansk | Deutsch | Ελληνικά | English | Esperanto | Español | Eesti | Euskara | فارسی | Suomi | Français | Galego | עברית | Hrvatski | Magyar | Bahasa Indonesia | Ido | Íslenska | Italiano | 日本語 | ქართული | 한국어 | Kurdî / كوردي | Latina | Lëtzebuergesch | Lietuvių | Bahasa Melayu | Nnapulitano | Nederlands | Norsk (nynorsk) | Norsk (bokmål) | Polski | Português | Română | Русский | Slovenčina | Slovenščina | Shqip | Српски | Svenska | తెలుగు | ไทย | Türkçe | Українська | اردو | Tiếng Việt | Volapük | 中文(简体) | 中文(繁體) | +/-
Creative Commons License
Creative Commons Attribution iconCreative Commons Share Alike icon		 This file is licensed under the Creative Commons Attribution ShareAlike 2.5 License. In short: you are free to share and make derivative works of the file under the conditions that you appropriately attribute it, and that you distribute it only under a license identical to this one. Official license
You may select the license of your choice.

The following pages on the English Wikipedia link to this file (pages on other projects are not listed):

Retrieved from "http://en.wikipedia.org../../../d/e/s/Image%7EDescenteInfinie.ogg_fea0.html"