Audacity Applying effects including adjusting volume and fade in and out Audacity makes it easy to apply various effects to recordings including fading in and out, increasing, decreasing or normalising volume and also removing background noise, which we'll cover in a separate tutorial. You might for instance be making a podcast and wish to fade in and fade out a short piece of music at the beginning and end of your podcast. You might also have a recording where the volume level is a bit low, or the volume of imported tracks is noticeably different, so increasing or normalising the volume would improve things. All of this is relatively quick and easy with Audacity. Here we have an extract from a JISC TechDis podcast opened in Audacity- To demonstrate some of these effects we will start by importing some music. Select File > Import > Audio and browse to a suitable music file. Audacity Sept/2013 Page 1 of 12
In this example we're going to use some music downloaded from http://freemusicarchive.org which we can use legally as long as we include an Attribution and link to the original artist such as Free Film Music (cameronmusic.co.uk) to Alastair Cameron. Depending on the length of the track it may take a while to import so we may see a progress bar. Then, when loaded we will see the additional tracks below our original recording. Audacity Sept/2013 Page 2 of 12
In this case we can see that the imported music is stereo (we see a left and right track) and also there's some silence at the beginning of the track before the music begins. We could simply select and delete that silence as covered in one of the other tutorials but on this occasion we'll use the Time Shift Tool. With the Time Shift Tool selected we can simply drag the music clip to the left, so that the music begins at more or less the same time as the speech or perhaps just before. Listening to the speech and music tracks together reveals that the music is too loud for the speech so we need to reduce it. We could use one or two of the options in the effects menu to reduce the music volume but in this example we will simply use the gain slider to reduce the volume while listening to all the tracks. Click play and slowly shift the slider to the left until the balance between music and speech volume is ok. Audacity Sept/2013 Page 3 of 12
We won't see any change to the track with this method but we can hear the difference and can easily adjust again or restore the music to its original volume. We can also easily fade the music in and out. With the selection tool selected simply select the beginning of the music tracks and drag to the right to select a suitable portion of the music. The more you select the more gradual the fade will be. Then select Effect > Fade In Audacity Sept/2013 Page 4 of 12
The fade is now applied but if we were to click play we would only hear the part we selected so we can click the Skip to Start button. Then click Play to hear all the tracks from the beginning. We could also select Edit > Undo Fade In (Ctrl + Z) if we weren't happy with the effect or wanted to apply it again to make the fade longer or shorter. If we continue listening to all tracks there's a point where the presenters have said who they are, which is where we want the intro music to end. We can select from this point to the end of the music and click the Delete key on our keyboard. Audacity Sept/2013 Page 5 of 12
However, that leaves an abrupt end to the music so we can use a fade out effect similar to the fade in used previously. Select a suitable section at the end of the music and select Effect > Fade Out. Audacity Sept/2013 Page 6 of 12
Now if we click somewhere in the middle of the tracks to clear our previous selection and then click play we should hear the music fade out just as the introductions end. We could repeat a similar process to add and fade in some more music at the end of the podcast but as this is just a demo we'll pretend this is the complete podcast and that we're ready to create the merged.mp3 file. There are a couple of ways we could do this. Firstly click File > Save Project to make sure all our changes are saved. If we think we might want to make further changes to individual tracks in our project, for example, if it's just a draft at the moment, or if we might want to change the music at some future point, then we Audacity Sept/2013 Page 7 of 12
can merge the tracks when exporting rather than merging everything within the project. Select File > Export and choose the relevant format in this case.mp3. We will probably see a Metadata form where we can add details such as Track and Album, Title etc. as well as a field for comments but in this case we'll just leave this empty and click Save. Audacity Sept/2013 Page 8 of 12
We may also see a prompt that our separate tracks will be mixed down to two separate channels in the export file - this is fine- click OK. Depending on the size of the file the export may take a while, and we'll see a progress bar after which our export will be complete. We now have an exported.mp3 where the original podcast and imported music tracks are merged into one stereo file, but we also still have our project with the separate tracks which can be edited or replaced separately. Audacity Sept/2013 Page 9 of 12
However there may be occasions where we want to merge multiple tracks within the project especially where we've made lots of additional recordings into separate tracks. In this case we can select all the tracks - Edit > Select > All (Ctrl + A). Then select Tracks > Mix and Render. We will then have a two channel merged project where the music and original recording are part of the same tracks. Audacity Sept/2013 Page 10 of 12
One final effect we might want to try and apply is called Normalisation. This will reduce any excessive volume levels within the recording and can result in more even volume levels across the whole project or just sections to which it's applied. In this case we'll normalize the whole project. Select Effect > Normalise. Then adjust or accept the default settings or select preview. In this case we'll just leave the default settings and click OK. Audacity Sept/2013 Page 11 of 12
When the progress bar automatically closes we can listen to the effect, undo it if necessary and then export to.mp3 like we did previously. There are many more effects and manipulations we can achieve with Audacity and lots of additional tutorials and help to be found on the web. A good place to start in addition to these JISC TechDis guides is the Audacity Wiki. http://wiki.audacityteam.org/wiki/audacity_wiki_home_page Audacity Sept/2013 Page 12 of 12