To apply compression, select the audio tracks or clips you want to normalize and click the “Compressor” option in the Effects tab.
There are 6x fields you can tweak to customize the effect.
1. Threshold
This setting determines the decibel range that you want Audacity to compress. Anything louder than your threshold will have compression applied.
2. Noise Floor
Setting your noise floor prevents Audacity from amplifying quiet pauses in your audio or in between your words and introducing noise when you readjust your gain after compression
3. Ratio
The ratio determines the amount of compression you want to apply. The higher the ratio, the more Audacity will reduce the peak volume of the loud parts of your audio.
4. Attack Time
How quickly do you want Audacity to respond to changes in volume?
5. Release Time
After the volume drops below your desired Threshold, how long until Audacity stops compressing the audio?
6. Make-up gain for 0 dB after compressing
Since the compressor reduces the peak volume of your audio, this amplifies your audio track and brings the overall volume level back up. You can also pair the Compressor effect with the Limiter effect, which forces your audio waveform to stay below a certain volume threshold, but only use the Limiter effect if you’re having issues with clipping or distortion.