AV News 200 - May 2015
Dynamic range reduction
Finding the correct level for background music so that it doesn't drown out a
commentary can be surprisingly tricky.
If the volume is fairly consistent throughout the piece of music, then the overall
level of the audio clip can be reduced. Even this is not straightforward, as what
sounds acceptable on home speakers can seem too loud when played to an
audience.
However if the volume varies
widely, as in most classical music,
then you need to resort to a volume
envelope as well. The idea is to
create an envelope that reduces the
louder parts of the music while
maintaining the volume of the
quieter parts. The envelope should
end up looking roughly the same
shape as the lower half of the dark
green part of the waveform
representing the original amplitude.
Figure 5 should make this clear.
When the music alone is played,
there should be little discernible
difference throughout the piece. The
overall level of the audio clip can then be adjusted as necessary.
Adding a commentary
The method I use to add a commentary to a sequence is as follows. It may
seem long-winded, but once set up, it does allow easy adjustment of the timing
of the slide transitions.
Record the commentary with pauses between the comment for each slide. If
you make an error, pause, then repeat the whole of the comment for that slide.
Save the commentary as an audio file. If it is a long commentary, record it in a
number of shorter sections about 4 minutes long. Open the PTE project. The
slides should already have been added but no audio. In Project Options add two
tracks. In normal view make sure you can see the commentary audio files in the
file list window (top left). Also make sure the timeline window is big enough to see
the first two tracks and the slides.
From the menu bar select Settings | Preferences and then the Timeline
section. Select 'Mixed channels' for the waveform view.
1. Drag the commentary file into Track 2 and reduce its size at either end so
that it includes just the comment relevant to the first slide. Look at the waveform
to see roughly where the pauses are, and then play to confirm.
2. Drag this clip to Track 1 and position under the relevant slide. Left click the
slide, then right click the audio clip. There should be an entry in the menu that
says 'Link Audio Clip to Slide n'. Select it.
Repeat steps 1 and 2 for the remainder of the slides. The procedure is a lot
quicker if you adjust the time span of the time line so that the whole length of the
commentary file can be seen at once.
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