editing audio using audacity

8/14/2019 Editing Audio Using Audacity

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Editing Audio Using AudacityAt this point, you should have audio files in the WAV or MP3 audio formats. If your

audio files are not in one of those formats, please see the Preparing Your Audio Files for

Editing and Other Uses handout for information on using iTunes to convert your audio

to those formats.

Audacity is a fairly easy-to-use program that allows you to import audio files, edit them,

clean up audio and mix multiples files together. Once the files have been edited to your

satisfaction, you can export them for use in Photoshop Elements, Premiere Elements or

other multimedia software. A free copy of Audacity is available for download at

http://audacity.sourceforge.net (download a regular version, not the Beta release). You

must also download and install the LAME MP3 encoder from this web site; it increases

the functionality of Audacity.

Setting up your WorkspaceWhen you open Audacity, go to Project Import Audio; in the file menu that pops up,

navigate to the audio files you wish to import. Each file will open in a track in Audacity.

We will refer to the window these files are open in as your source window.

Once you have your files open, go to File New; the window that opens will be the

workspace for the project you want to create. Then go to Project New Audio Track,

and create a new audio track. You should perform this step once for each clip, or piece of

audio that will be used in your finished project. For example, if you have eight audio

clips you plan to use, youd have eight new audio tracks. We will refer to this window as

your destination window. You are now ready to begin editing.Tools at your DisposalThe Selection Tool

Click this icon and your pointer can be used to highlight portions of the audio

file. This allows you to edit and apply changes to individual portions of the

file.

The Zoom Tool

Click this icon and your pointer can be used to zoom in or out on the audio

track; left click to zoom in, right click to zoom out. This can be useful whenediting the audio, since you can see more detail in the waveform and

determine exactly which parts of the audio correspond with certain sounds.

The Time Shift Tool

Click this icon and you can move the audio in a track forward and backward

along the timeline; this is used to determine when a clip should start or finish

playing in relation to the audio in other tracks in the current project.


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Basic Editing OperationsSince you have multiple files open in the source window, you would hear all of the files

at the same time if you were to press play. At the left-hand side of each file, there is a

small set of controls, including a Mute button. Press the Mute button on every file except

the one you want to take your first piece of audio from. You will now be able to hear thataudio file alone.

After playing your audio file to determine the start and end points, you can use the

selection tool to highlight the section of the file you want to use. Highlighting works just

like it does in Microsoft Wordclick and drag to highlight the part you want, then use

the copy button or the copy command to copy the selection.

After copying a clip, go to the destination workspace and use the paste button to paste the

selection into an open audio track.

If you like, you can also use the keyboard shortcuts Ctrl+C and Ctrl+V to copy and pasteinstead of using the copy and paste buttons in Audacity.

Once a clip has been pasted into an audio track, you can select the Time Shift Tool and

move the clip forward or backward its track in the timeline until it is located where you

want it relative to the other audio clips in your story. Once youre done time-shifting

your audio, select the Selection Tool so youll be ready to paste your next audio clip.

Repeat the cycle of copying audio, pasting audio and using the Time Shift Tool several

times, and your story will look something like this:


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EffectsIn the Effects menu, you will find several options for improving your piece.

If you need to change the volume of part of your track, highlight

the area you want to adjust, then go to Effects Amplify. Thisbrings up a menu with an adjustment slider. The slider defaults to

the highest amplification possible, without clipping. Use the

preview button to get a sample of what the selection now sounds

like. If this is not enough, check the Allow clipping box and

move the slider to the right or left to increase or decrease the

volume. Clipping will decrease the quality of the audio.

If you are trying to increase the volume, but the Amplify tool doesnt increase it

enough, you can increase the gain by using the gain control at the left end of the

timeline for that track; the slider with the -/+ scale is the one to manipulate. But only

do this as a last resort. When you increase the gain, the audio quality suffers.

If you have natural sound or music in the background of your piece, you may want the

volume of this background sound to gradually fade in at the start of your story, fade out at

the end, or to gradually change volume before your narration begins or ends. To make

such a gradual transition, highlight a few second of the audio at the transition point, then

use the Fade In (gradually increase volume) or Fade Out (gradually decrease volume)

function under the Effects menu. Play with these functions to get the effect you want;

this is more an art than a science in Audacity.

Sometimes, you may have unwanted noise in your audio track, such as a ceiling fan

humming or a buzzing from your recorder. In certain circumstances, you can reduce oreliminate this noise with the noise removal tool. This is a two-step process. Well use

the audio from your interview as an example.

First, go back to your source window and find an area in the

interview where neither you nor your subject is talking. Highlight

this area. Then, go to Effect Noise Removal. A window will

popup with two steps. Youll want to push the button that initiates

Step 1, Get Noise Profile. After pressing the button, the Noise

Removal tool will close; this is normal.

Next, go to your destination workspace and highlight the sound byte youwish to remove noise from. Then, go to Effect Noise Removal, which

will reopen the Noise Removal Tool. You can now use the controls in

Step 2 to adjust the amount of noise you remove. Use the preview button

to review your work; you must make sure not to distort the audio youre

keeping. When satisfied, press the Remove Noise button. The shape of

the waveform in the area you highlighted will change, indicating the

removal has been completed.


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Advanced Tools and EffectsThe Envelope Tool

In your tool bar, you probably saw the button for the Envelope Tool. The

Envelope Tool gives you the ability to fade in or out in the middle of a track or

make gradual volume changes over a period of time. This is for more advancedor longer stories; for basic stories or users who are new to Audacity, you should

stick with the simpler fade and volume controls mentioned earlier in this document.

After selecting the Envelope Tool, when you move your cursor over the audio

tracks, it will resemble the logo for the Envelope Tool. Once youve activated the

tool, youll want to create what are known as control points. Control points mark

the start or the end of a change in amplitude, and are what you manipulate in order

to make that change in amplitude. To create a control point, click on the audio

track you wish to edit, and a set of white dots will appear. This is your first control

point. If you click somewhere else on the same audio track, your second set of

control points will appear.

Once you have your control points, you can create your fade effect. For

example, lets say you wanted your audio to increase in volume. Place

your cursor over the first control point, hold down your left mouse

button, and drag the control point up or down to the volume you want

the start of your fade effect to be at. After releasing the control point, do the

same thing with your second control point. Your audio track would now look

like the example to the right.

If you wish to change the location of a control point, place the cursor over that

control point, hold down your left mouse button, and drag the point left orright to its new location.

You can also use the Envelope Tool in place of the Amplify effect to change

the volume of an entire audio track. If you create a single control point, you can

manipulate that point until the volume of your track is at a level youre satisfied with.

High Pass and Low Pass Filters

The High Pass and Low Pass Filters can be used in place of or in addition to the Noise

Removal tool to remove interference or unwanted noise from your audio track. This

works best if you know the approximate frequency of the noise youre trying to remove;

otherwise, it becomes a trial and error process rather than an exact science.

Be Careful When Highlighting AudioWhen youre highlighting an audio track you plan to edit, make sure your cursor stays

over the track you wish to edit. If you sweep over a neighboring audio track, youll also

highlight that neighboring track.


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The Pause ProblemIf you are listening to audio in Audacity and you press the Pause button, most of the

tools and menus will be disabled. You cannot edit the audio while it is paused. You

must press the stop button to regain functionality. Thats just the way it is.

The Project Sample Rate ProblemYou may experience a problem where some of your

audio, when pasted into the destination window,

changes speed. It may sound like the speed is doubled.

If you look in the settings box to the left of that audio track, youll

notice below the name of the track is a number followed by the

letters Hz. That is the project sample rate in hertz. After pasting

audio into your destination window, make sure the sample rate in

that destination track matches the rate in the source track.

To change the sample rate, click on the arrow next to the track name. This will open a

drop-down menu. Go to the bottom of the menu, to Set Rate. In the menu that opens

to the right, set the sample rate to match the rate in your source track.

ExportWhen you have finished editing your audio, youmust export your project as a WAV or

MP3 file. Your Audacity project is not an audio file. Your professor or lab instructor

cannot open the Audacity file for playback; other software programs cannot read the

Audacity files for further use. The only way your project can be graded or importedinto another piece of multimedia software is to export it as a WAV or MP3 file!!

To export your project as a WAV, go to File Export as

WAV. Save the file on the desktop of your computer; name

it after yourself if you are turning it in after export, name it

something logical if it is to be imported into another program

with other files.

To export as an MP3, go to File Export as MP3 and follow

the rest of the export instructions in the previous paragraph.

The exported file can now be turned in to your professor or

lab instructor, or imported into other programs for further

use.

10/08 Paolelli/Love

editing audio using audacity

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