More about Audacity
If you are used to using software, you will find that editing sound is
very similar to manipulating words or images.
These notes are designed to highlight some of the points where sound editing
follows a slightly different route from text editing. You can of course read all the instruction
by clicking Help inside Audacity.
You need to understand that the vertical component of the sound display
represents the volume. You will soon learn to identify some sound shapes. It
is a
bit like learning to read. Soon you will be able to 'read' musical instruments
from the sound wave-shape.
Starting a project involves getting some sound files by importing or
recording.
 | Make sure you have selected the mic as the source. |
| Click 'Monitor' on the drop down menu and start talking to see that the
connection is working. |
| The press record and everything you say will be recorded. |
| You can press pause or stop when you need to draw breath.
| If you press pause, the recording starts again on the same track. (None
of the other buttons work while you are paused) |
| If you press stop then the recording is on a new track . |
|
The project menu offers some useful tools.
| Align Tracks offers various ways to get rid of clicks and silences. |
| Quick Mix puts all the selected track together permanently, saving
storage-space. |
Setting the volume
All the output devices produce signals at different levels. You need to set
the gain control to ensure that the signal levels are suitable for your software
and electronics. The signal should neatly fill the display. If it is too low,
you get a lot of background noise. If it is too loud, you get clipping.
Setting the quality
| Each sample of audio has a 16-bit depth or 65,536 possible levels which
represents the volume of the sample. |
| 48-56k mono is fine for talk. But much lower rates work fine if they are
just for information or trailers. |
| If you are including music a 64k sample rate might be better and this will
give you stereo. |
| Stereo needs 128k sample rate (i.e. 2x64k). |
| So with 48,000 samples each with over 65,000 variants (16-bit sample,
48kHz rate) a stereo digital audio needs about 11Mb for each minute. |
You need to select the sample rate BEFORE you record.
The sample rate makes an enormous difference to the size of file that will be
produced.
Viewing
| History shows all the actions performed during the current session.
This allows you to undo sound experiments that don't work. |
| Float lets you move most of the controls and meters to suit your
screen. |
Editing
| Cut is a useful way to get rid of any place where you fluff your
lines. Just highlight and select the scissors. |
| Copy lets you copy a chunk and paste it on the end. |
| Delete removes without copying to the clipboard. |
| Silence erases the selected section, replacing it with a gap with
no sound. |
| Duplicate copies all or the selected part to a new track which it
creates for you. |
| Split moves the selected section to a new track, leaving silence in
its place (unlike duplicate). |
| Find zero crossing modifies any section selected so that subsequent
operations won't produce a 'click'. |
Effects
| Compressor selectively reduces the loud parts, unlike the gain
slider which reduces the dynamic range of all the wave-shapes. |
| Echo provides some depth to a studio sound. Don't forget to add
some silence if you want to hear the echo to fade. |
| Noise Removal can be a good way to clean up a live recording. It is
important to have a section of the unwanted background noise which you can
tell the software to remove. |
The key point to remember is that when you add sounds, you increase the
volume. Because this is a logarithmic scale so it is not the same as adding
2+2. Just take care when combining loud sounds. Use the gain-slider or envelope
tools to reduce the volume and avoid clipping.
It takes a few goes to get the hang of it but by the time you have mastered
all the hardware you will be an expert with the software.
Saving
You can save the project to keep it for more editing later.
Then use the export option to save as an MP3 (You need to download
some more software which should have happened when you installed Audacity).
MP3 will combine all of the tracks. If any of them overlap, it will combine
them.
Fill in all the information as this is used by RSS to let the web know of
your audio file. Make sure you provide a way for people to find your book.
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