Any Mac user who records audio has similar problems experienced by other Mac users who record audio. One of the most prominent is keeping audio levels steady within a recording, especially a podcast. Most popular Mac audio recording apps have a way to normalize audio files to mash down strong audio signals while enhancing lower signals.
The application of a constant amount of gain to an audio recording to bring the average or peak amplitude to a target level (the norm). Because the same amount of gain is applied across the given range, the signal-to-noise ratio and relative dynamics are generally unchanged. Normalization differs from dynamic range compression, which applies varying levels of gain over a recording to fit the level within a minimum and maximum range. Normalization is one of the functions commonly provided by a digital audio workstation.
Easier said than done properly.
For Mac users who record audio but have a budget to adhere to, here’s a free tool which adjusts audio levels– normalization– within any popular Mac audio file, including podcasts. It’s called Levelator. The utility has been around awhile and development stopped in 2012, but was recently upgraded to work with OS X 10.11 El Capitan. It also works on Windows and various flavors of Linux.
Levelator is much easier to use than a compressor or limiter app to achieve normalization. Just drag and drop any WAV or AIFF file onto Levelator and you get a normalized version; essentially, another file which sounds a bit more clear, and a bit louder.
That’s it. Levelator normalizes the file then saves a copy in the same folder as the original. There are no settings to adjust, nothing to tinker with, nothing to tweak. Drag and drop a WAV or AIFF audio file and you get one just like it, but normalized.
Nearly every Mac audio recording app I’ve used in recent years has an option to normalize an audio file, and most of those have controls to adjust settings, including option to normalize to a specific dB level, normalize stereo channels independently, maximize the sample value, or maximize RMS power (an audio setting).
Levelator has none of those options. It’s free and it’s drag and drop simple. The only negative is that it handles WAV and AIFF files, but not MP3, AAC, or any others, but that’s a nit.
Similar functionality exists in Garageband, but usually requires tinkering with compressor and limiter settings to achieve the same thing as drag and drop in Levelator.