Attached is the "stereo widener" plug-in which someone had asked me about off-list, an effect which works with Audacity. It creates the illusion of widening your stereo audio (making it sound like your speakers are further apart than they really are, whether in your headphones or part of your computer and/or stereo system). Stereo widening effects will be different depending on the distance between your speakers, where you are physically in relation to them, and the settings you have used in the Stereo Widener plug-in. I've set the default values of the three numbers (explained below) so I hear stereo widening effects in my headphones.
If you want to install and use it, copy the attachment (called widener.ny) into your Audacity plug-ins folder, usually
in Windows. The next time you re-start Audacity, you will find "Stereo Widener" under the effects menu.
To make the stereo widener work, first load stereo audio into Audacity, select the audio you want to apply the effect to, open the effects menu (alt+c in Windows), and cursor until you get to Stereo Widener. (You can also press the 's' key to get to it much faster). Click on Stereo Widener.
There are 3 edit fields:
1. Inverted signal volume - db A widener works by first inverting a stereo signal (multiplying the left and right channels by a negative number, so the audio waves become upside-down or "inverted"). The default value is negative 18 db, a very low volume, but which you can change between negative 48 db (very very low volume) and negative 6 db (half normal volume).
2. Pan position A widener also needs to change the position of the inverted signal (called "panning"), closer to the opposite channel. The numbers range from 0 (panned to center, the default value) to negative 100 (panned to the opposite channel, for instance the right inverted channel panned to the left channel position).
3. Time offset A third way of enhancing the illusion of widening stereo is to also "delay" the inverted signal slightly. For instance, you can have them delayed up to 20 milliseconds (0.02 seconds) after the original signal. The default is 0 delay time.
Written by David R. Sky, March 19, 2006. Released under terms of the GNU Public License http://www.opensource.org/licenses/gpl-license.php
widener.ny is a "Nyquist" plug-in. Other Nyquist plug-ins plus example mp3 files are available for download from:
Other Audacity Nyquist resources and plug-ins are posted at:
;nyquist plug-in ;version 1 ;type process ;name "Stereo Widener..." ;action "Widening stereo audio..." ;info "by David R. Sky\nReleased under terms of GNU Public License\n-Pan: -100=opposite channel, 0=center" ;control vol "Inverted signal volume - db" int "" -18 -48 -6 ;control p "Pan position" int "" 0 -100 0 ;control offset "Time offset - ms" int "" 0 0 20 #| Stereo Widener by David R. Sky, October 18, 2004 Updated March 19, 2006 Thanks to David Walsh and Monty of the Audacity-users list for discussion and explanation of how to widen stereo. Should work properly for both North American and European audacity-Nyquist - N American uses . for decimal European uses , for decimal so calculations are done using floating whole numbers (see two setf statements) How it works: left and right channels of a stereo signal are both inverted and attenuated to some degree, then panned somewhere between center pan position and the opposite channel, depending on pan position setting. (0=center, -100=opposite channel). The inverted signals can be offset in time to enhance the illusion of stereo widening. |# ; Stereo Butterfly function - used to ; change the width of the stereo field. (defun butterfly (sound width) (vector (sum (mult (aref sound 0) (sum width 1) 0.5) (mult (aref sound 1) (sum width -1) -0.5)) (sum (mult (aref sound 1) (sum width 1) 0.5) (mult (aref sound 0) (sum width -1) -0.5)))) ; convert arguments to floating values (setf offset (/ (float offset) (float 1000))) (setf p (/ (float p) (float 100))) ; applying stereo widener (if (arrayp s) (sim (cue s) (at-abs offset (cue (butterfly (mult -1 (db-to-linear vol) s) p)))) (format nil "You must apply the stereo widener to stereo audio.") )