[audacity4blind] Nolan: Duck audio plug-in

  • From: "David R. Sky" <davidsky@xxxxxxxxxxxxxx>
  • To: audacity4blind@xxxxxxxxxxxxx
  • Date: Fri, 15 Jun 2007 07:19:58 -0700 (PDT)

Hi Nolan,

Attached to this post is duck.ny , an effect plug-in to duck your selected audio by the amount you set.

Copy duck.ny into your Audacity plug-ins folder, typically

c:\program files\audacity\plug-ins

Start an Audacity session, load audio into Audacity.

1. select audio you wish to duck and later talk over.
2. Open the effects menu.
3. Click on 'Duck audio...".
4. There are two edit fields:

Duck audio to this level [db]
default is negative 6 db, range from 0db to negative 12db.

Fade-down and fade-up times
default is 200 milliseconds, range from 0 to 500ms.

5. Press return or click on the okay button.

When you press the space bar to listen to the results, you should now hear it
start at full volume, drop down to the level you selected for almost the full duration of your selection, then rise up to full volume at the end of your selection.

Anything you want me to clarify or change, please let me know.



David R. Sky
;nyquist plug-in

;version 2

;type process

;name "Duck audio..."

;action "Ducking audio..."

;info "duck.ny by David R. Sky www.shellworld.net/~davidsky/nyquist.htm 
\nReleased under terms of the GNU Public License"

;control duck-level "Duck audio to this level [db]" int "" -6 -12 0

;control fade "Fade-down and fade-up times [milliseconds]" int "" 200 0 500

; Duck audio by David R. Sky, June 15, 2007.

; http://www.shellworld.net/~davidsky/nyquist.htm

; Released under terms of the GNU Public License

; http://www.opensource.org/licenses/gpl-license.php 

; convert duck-level from db to linear

(setf duck-level (db-to-linear duck-level))

; convert fade times from milliseconds to seconds

(setf fade (* fade 0.001))

; get selection duration

(setf dur (/ len *sound-srate*))

; convert fade time to percentage of selection duration

(setf fade (/ fade dur))

; duck audio

(mult s (pwl 0 1 fade duck-level (- 1.0 fade) duck-level 1 1 1))

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  • » [audacity4blind] Nolan: Duck audio plug-in