In this article we are dedicated to the fabled theme of compression. You may not know every peculiarity of a particular compressor plug-in or a hardware compressor at first glance. However, attentive reading will help you to understand the application and basic operation of a compressor and its influence on dynamics. We show you the most common parameters of the compressor: threshold, ratio, attack, release, knee and output gain. In addition, we provide an overview of the various compressor variants, the tube compressor, the optical compressor, the VCA compressor and the FET compressor.