10 Tips for using an audio compressor in the mixdown.

1. The best audio compressor is the one whose presence is not heard at all. (Apart from exceptions such as side-chain compression in EDM).

2. A compressor does not increses the signal, but it reduces peak levels. Only the Make Up Gain will raise the level.

3. This does not make the loud sections of the music louder but the quiet.

4. The compressor reduces the original dynamics.

5. Problematic are the transients (fast attacks), for example of an acoustic guitar. The transients compressed at first, because they have a relatively high level. This reduces the level, but also the original sound, because transients are very important for the sound.

6. Voices can be easily reduced because they have very few transients. 12 dB and more (recommended ratio 4: 1) are pssible.

7. But with a strong voice compression, the breather and other background noises are much louder.

8. With the side-chain input, the work of the compressor is not controlled by the input signal, but by the signal that is present at the side-chain input.

9. For example, a synthesizer in a mix can be automatically quieter when the voice is applied to the side-chain input. This creates space for the voice and makes a mix lively.

10. In the parallel compression, the compressed signal and the uncompressed signal are interconnected phase-stiff. This way you can increase the low level signal and keep the original transients. (Dry control)

Stefan Noltemeyer  
www.mastering-online.com