Presentation Magazine

How to use Audacity – Part 2


Audacity logo

In Part 1 we covered an overview of Audacity looking at the various features and functions of the program.  In this final article I will touch on the basics of preparing and exporting an ‘mp3’ sound file ready to be inserted into PowerPoint.  I have used a music track for this article but it could just as easily have been a few minutes of narration that needs tweaking.

waveform-of-the-trackHere you can see the actual waveform of the track. Because the track is stereo you can see the left and right channel one above the other.  The taller sections of the wave are the louder sections of the music, while the quieter sections can be seen at the very beginning and shortly afterwards.  This ‘snippet’ represents just over 4 minutes, represented by the 4:00 in the timeline.  As you play a track the small green triangle with a vertical line on the timeline will indicate where in the track you are.

Let’s assume for the sake of this article that we have an audio track that will be used as narration for the presentation.  Furthermore, we have a couple of problems that need sorting out before inserting it.

  1. The entire track needs amplifying due to it being recorded at too low a level.
  2. The voice used when played back sounds a little ‘trebly’ and you would like to add a little bass to the overall track.
  3. Someone slammed a door just as you got started and you need to remove it from the recording.
  4. The track is longer than the presentation by one second.  You have some silent sections that you can safely cut out so it will be relatively easy to accomplish.
  5. Finally you would like to fade in and fade out the narration to add that ‘panache’ to the feel of the narration.

EFFECTIVE EDITING

There are a host of effects that can be used to tweak your audio track; I will not pretend to know what they are all for.  If you click this link you can read the help section dedicated to effects.

1. Amplifying the tracks

Amplifying-the-tracks

First of all, select the entire track – CTRL+A.  Then click ‘Effects’ from the menu bar. Topmost on the effects list is ‘Amplify’.  Click that and a small dialog window opens like this.  I would accept the default of 2.1 one to begin with and then click ‘Preview’ to gauge the effect.  If you choose to accept the change the amplification will be applied and the waveform will expand accordingly (vertical axis).  If it’s not enough simply repeat the effect, changing the (dB) figures to suit.  If it’s too much you can either hit CTRL-Z to undo the change or apply a negative -2.1, in this example, with the same result.

2. Adding some bass to give that edge to your voice

If it needs it, of course.  Adding-some-bassAs in point 1, select the entire track and then BassBoost from the ‘Effects’ list.  I would not use the default here as in my test this added quite a lot of bass.  The lower the ‘Hz’ figure the lower the bass tone.  The lower the ‘dB’ the smaller the boost.  Remember to use CTRL+Z to undo any change you make if you overdo it.  Don’t forget the online manual.

3.    Now for that door slam

In my waveform example above you can see a loudish piece at the beginning which becomes quiet and then loud again.  I will remove this from the track.  It really is easy.waveform-example

a.    First click anywhere on the section of track you wish to start removing and drag to approximately where the end would be.

b.    Play the section, listening to where the start of the noise to be removed begins and ends.  You can nudge the start by pointing the mouse at the left or right edge and push/pull to get the exact spot.zoom-functions

c.     If the selection is too small to get an accurate start and end you can zoom the selection using the magnifier tools.  The third icon on the right will zoom the selection to fit the window.  You can then nudge the start and end until you have a precise selection.

d.    To remove the selection simply hit the delete key or the ‘scissors’ icon.

Your track is now almost ready, apart from the fact that it is a bit too long for the presentation.  If it is a narration you are likely to have short periods of silence that you could shorten by an amount that would shorten the overall length of the track.  To remove a set period of silence follow these steps.

e.    Find a section of silence in the track.  A flat, or near flat, line is what you are looking for.

f.    Zoom right in so that almost only that section of silence is in the project window.  What we want to achieve here is to get just a few seconds of timeline in the window.  This snapshot shows exactly one second of the timeline.

exact-position-of-your-start-and-endRemember, you can use the nudge tool to get the exact position of your start and end.  The cursor changes to a finger pointing left or right as you hover next to the left or right edge.  Simply click and push or pull to drag the selection edge.

g.    To delete the selection hit delete or use the ‘scissors’ icon.

4.    Fade in / Fade out

There are two ways to do this.  Easy one first.

a.    With NO part of the track selected, simply choose ‘Fade in’ / ‘Fade out’ from the ‘Effects’ option in the menu bar.  A pre-set period of fade will be added to the start or end of the track.  The fade is quite long and may not be to your liking, so try step b, which is user defined.

b.    Select the period of track you wish to fade.  Zoom the track to get the exact length, as described elsewhere in this article.  Now select ‘Fade in’ or ‘Fade out’ and watch your selection fade.  If it’s not quite right when you play it back, then simply undo and try again with either a shorter or longer period.

This last point can be very useful if you wish to fade from intro music to narration, for example.  All you need to do is select the end of your music and fade it out and then fade in the narration.  Of course, the same technique can be used at the end of the track.

All that remains now is to save your masterpiece.  As mentioned in Part 1, you will need to export to save as an ‘mp3’ file.  To save as a project, use the ‘Save Project’ option.

You can then insert the file into your PowerPoint presentation.

Article written by Alan Cooke.

 

Published On: 21st Nov 2011

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