Audacity is a free audio editing program available for Windows and Mac. Visit the Audacity download page, and choose the appropriate link for your operating system. Follow the instructions on the website to download the Audacity installer to your computer, and then run the installer.
You will also want to follow the instructions on the download page to install a few useful plug-ins. The LADSPA plug-ins, LAME MP3 encoder, and FFmpeg import/export library are recommended to get the most use out of Audacity. Follow the instructions on the website to download and install these plug-ins.
There are several easy ways to get audio into Audacity to begin editing. You can import audio files from outside sources (audio recorded on a separate device and copied to your computer’s hard drive, files downloaded from the Internet, etc.) by going to File > Import > Audio, or dragging and dropping audio files directly into the Audacity window. You can also record audio directly in Audacity using your laptop’s internal microphone or an USB microphone. You can change the microphone settings on the toolbar or by going to Edit > Preferences.
Once imported, audio will appear as a blue waveform. You should see one or two waveforms on the screen, depending on if your video is in Mono or Stereo. You will want the waveform to fill its bar, but not allow the peaks of the wave to exceed the bar, as this will cause distortion to the sound.
You can also import multiple audio files into one window, which will be covered below.
Use your pointer to highlight a portion of the waveform. You can now use editing tools like cut and copy on the toolbar to rearrange or delete clips. Click to add a cursor line in the waveform and use paste to add the clips on your clipboard into that location. You may find it more precise to hold the shift key and use the arrow keys in either direction to expand your selected area. In conjunction with the zoom options on the tool bar this can make it simple to focus on just the audio you need for your project.
You can have several tracks in audacity at the same time. The tracks will play over each other, so when you are cutting content into a finalized track you may find it easier to have multiple audacity windows open at the same time. Use File > New to open a new window, you can copy and paste audio from one window to another.
When you export your project into a sound file, all tracks will be reduced down to a mono or stereo track, depending on your settings. This is useful for adding narration over other audio, such as music. Use File > Import > Audio to bring a new audio track into your current window. Tracks can be edited separately to line up or fit audio with each other, then export it as a single audio file for use in other programs.
Volume can be controlled for each track by using the sliders to the left of the waveform. You can also use the Amplify effect to increase or decrease the volume of any portion of the audio by highlighting that section of the waveform, going to Effect > Amplify, and adjusting the values up and down in the menu. Just remember to keep the waveform in the bounds of the window. The Undo command can be used to try an effect then remove it, so feel free to experiment.
Another useful effect is Noise Reduction, which is used to remove regular background noise and static. First you must collect a “noise profile”. Find a section of your audio where only the background noise is audible, such as long pauses. The larger the profile you give Audacity the better it can reduce the noise, but the sample doesn’t need to be super long. Once you highlight the noise-only section go to Effect > Noise Reduction. In the Noise Reduction menu you should see a button labeled “Get Noise Profile”, click it to import your highlighted section. The menu will close, return to your waveform and highlight the portion of it (or all of it) that you want to remove noise from. Return to the Noise Reduction menu, the OK button should be active now. You can also adjust the amount of the reduction applied to your project using the sliders. It is best to use as little as possible, since using Noise Reduction can add odd sound artifacts to your project. Make sure to listen to any section you apply this to, and feel free to undo and try again if things don’t sound right. Also keep in mind this only works for noise that is repeated throughout the audio, one time background noises are much more difficult if not impossible to remove cleanly.
There are many other effects available for your use. The best option for learning about them is to try them yourself on test audio, or search the web for information on them. Some you may find of particular use are the Fade In and Fade Out effects, which are self-explanatory, or the Normalizer effect, which can balance the audio volume of your project.