Levelator, Adjust Audio Levels Automatically

The Levelelator has been designed for the purpose of adjusting the audio levels of podcasts and interviews. If you listen to podcasts regularly, you may have encountered variations from one speaker to the next. Maybe one speaker was louder or quiet than the other.

While leveling the audio of podcasts, interviews and panel discussions is the core purpose of the free application, it can be used to level and normalize any kind of supported audio format. The supported audio formats are without doubt the greatest restriction or usability issue. Only wav audio and aiff audio formats are supported by the program.

Usage on the other hand could not be simpler. The Levelator comes without options or settings. All you need to do to level an audio file is to drag and drop it into the program interface.

The program displays a progress bar while doing its magic. The modified audio file is then in the end saved in the same directory as the original file.

The developers reveal a bit about the background process on the program website:

here are some hardware devices such as various AGC (automatic-gain control) components that can do moderate leveling, but since they have to operate in real time (i.e., without look-ahead), they can't do much. And they aren't cheap, let alone free. Even a skilled human can only react to changes unless s/he is lucky enough to be present during a recording session and can use visual cues to anticipate coming variations. Software can do better by performing multiple passes over the audio, generating a loudness map of where the volume changes. (It's not actually that simple, but the metaphor is helpful.)

Bruce, with help from his son, Malcolm, had proven that he knew how to tackle these problems in ways that no one else anywhere in the audio/software industry has done to date. So we asked him, "Bruce, do you you think you can write a leveler that corrects for medium-term variations in loudness instead of the short-term and long-term variatons processed by compressor/limiters and normalizers, respectively?" Bruce and Malcolm took on the challenge, and eight months later we began testing The Levelator.

The big limitation of the program is the short list of supported audio formats. Many podcasts are not offered as wav files but mp3, which means that you will have to convert the mp3 files first to wav before you can use the program to level the audio. That may be fine if it is one or two audio files that you need to correct, but not so much if we are talking about dozens or even hundreds of files.

The Levelator is offered for Windows, OS X and Linux based operating systems. Interested users can download the free program from the project website.

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