Once you’ve sucessfully inserted the 16 seconds of silence into your file, you need to lower the volume of the music track so that the voice-over can be heard over the music. Select the portion of the music track that corresponds to the voice-over to the end of the recording. Select Effect->Amplify, enter -6.0 into the Amplification (dB) field to lower the volume significantly. See Figure 6. Repeat the amplify process to lower the music more, if necessary, but do so incrementally so that you can check the results at each stage of the process.
Figure 6: Lowering the Loudness of the Music Track
For further enhancement and a more professional sound, select the portion of the music track that follows the voice-over, select Effect->Fade Out to fade the music to silence as shown in Figure 7. Fading out the music creates a better transition to the next portion of the recording than ending the music abruptly.
Figure 7: Using the Fade Out Effect on the Music Track
Once you have your tracks situated like you want them, you’ll want to save them as a single file. Do this by exporting the workspace (File->Export) out to a file type (MP3, Ogg Vorbis, WAV) for your audience or as recognized by your external application.
Audacity is powerful but simple in its design, which makes it a versatile and elegant application for sound mixing, editing, and manipulation. Such applications can be intimidating for the first-time user but Audacity is readily usable by anyone who’s ever used a VCR, DVD, or any music-related gadget. You’ll find that you can be productive with Audacity after a few short interactive sessions. No lengthy or expensive training required. Audacity is fun, free, and ready to go to work. Enjoy.
If you’re looking for a more thorough treatment of Audacity, check out the online documentation or the new The Book of Audacity from No Starch Press.