[audacity4blind] Re: Using the duck function
- From: David Bailes <david_bailes@xxxxxxxxxxx>
- To: "audacity4blind@xxxxxxxxxxxxx" <audacity4blind@xxxxxxxxxxxxx>
- Date: Wed, 23 Apr 2014 09:49:44 +0100 (BST)
Hi Johny,
here are some notes on Auto Duck.
The Auto Duck effect reduces the volume in the selected audio during the
periods in which the level of another track, known as the control track,
exceeds a certain threshold. The track which is used as the control track is
the last unselected track which is immediately below a selected track.
So, for example, if you've got one music track, and one voice track in the
project, and you want to reduce the volume of the music when there's speech in
the voice track:
1. Make sure that the music track is the first track. If it isn't, you can move
a track up or down the track table by opening its menu, and choosing Move Track
Up or Move Track Down respectively.
2. Make sure that the voice track is not selected.
3. Select all the audio in the music track. To do this, first make sure that
the track is selected. Then select a time range that includes all the audio in
the track: press J to move the cursor to the start of the audio in the selected
track, and then press Shift + K to select from the cursor to the end of the
audio in the selected track.
4. On the Effects menu, open the the Auto Duck dialog, and if you've happy with
the default settings, then just press Enter to press the default OK button.
Auto Duck settings
* Duck amount. This is the amount of volume reduction of the selected audio
during the periods when the level in the control tracks exceeds the threshold.
Its given in decibels, and its default value is -12dB.
* Maximum pause. If the time between two periods when the level in the control
track exceeds the threshold is less than the Maximim pause parameter, then the
selected audio continues to be ducked in this time – there isn't a fade up and
then a fade down. If for example the control track contains speech, then if
there are pauses less than the maximume pause, then the selected audio
continues to be ducked during this period. The default value of Maximum pause
is 1 second. Note that regardless of this setting the Maximum pause is always
at least the sum of the outer fade lengths, which are described below.
* Fade lengths. The time over which the volume in the selected audio is faded
down to the reduced volume is made up of two parts. The volume of the selected
audio can start to fade down before the level in the control track starts
exceeding the threshold. This time interval is known as the outer fade down
length, because it occurs outside of the time when the threshold is exceeded,
and its default value is 0.5 seconds. In addition, the volume can finish fading
down after the threshold starts to be exceeded. This interval is known as the
inner fade down length, because it occurs inside the time when the threshold is
exceeded, and its default value is 0 seconds.
In an entirely similar manner, the time over which the volume in the selected
audio is faded back up is also made up of two parts: the inner and the outer
fade up lengths, which have default values of 0 and 0.5 seconds respectively.
* Threshold. The selected audio is ducked during the periods when the level in
the control track exceeds this threshold. It's given in decibels, and its
default value is -30dB.
David.
On Tuesday, 22 April 2014, 12:18, Johny Cassidy <johny.cassidy1@xxxxxxxxx>
wrote:
Hi
This is for anyone who knows how to use the auto duck function. It would be
great to get a simple walk through of how it wourks. Also, how to bring volume
down and up if making a package.
Johny Cassidy
Today programme and BBC Business News
New Broadcasting House
London
TEL: 0203 6142555
Mob: 07900 513293
TWITTER: https://twitter.com/johnycassidy
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