Professionally edited audio files go through a lot of changes post-production. If you’re new to recording any sort of audio, it is possible that the tracks/files you have contain quite a few silent parts. The audio file will pass through several rounds of editing and in that editing process, you can probably cut the silent parts out. This can take time though and it’s often an inconvenient stop within the editing process. If you’d like to automate the process, Audacity has a built-in feature that does the job.
Remove silence from an audio file
Open Audacity and add the file that you’d like to remove audio from. Silence is indicated by the wavelength going flat. Double-click anywhere on the track to select all of it, or just click and drag over the part of the audio file that you’d like to remove audio from to select it.
Once the audio file or part of the audio file has been selected, go to Effects>Truncate silence.
In the window that opens, look at two fields; the ‘Duration’ field under ‘Detect Silence’, and the ‘Truncate to’ field under Action.
The duration field is how the app identifies silence i.e., if there is nothing spoken or sung for 0.5 seconds, it indicates a silent portion in the audio file. The ‘Truncate to’ field indicates how much of the silence will be clipped. It will leave only 0.5 seconds of it and this should be enough in case you need to mix and rearrange bits of the audio later. It will make it so that different parts of the audio are still easy to distinguish from each other.
Start out with these default settings but if they leave you with too much silence in the file, or they cut out actual audio, you can undo the change and then change these parameters when you truncate silence next time.
Click OK, and all silent parts will be removed from the audio track. As a result, the track will be smaller in length. The change in length depends on how much of it was cut out because it was silent.
If you’re happy with the audio that you have, you can continue editing it and save it. While you can now overwrite the original file, we don’t recommend doing it. It’s always a good idea to have the original audio available until you’re finished with a project. In some cases, retaining the original audio file indefinitely might be a good idea so when you save the file with the edits, save it with a different name.
To save the file, go to File>Export.