A compressor is a type of processor very commonly seen in the mixing process, it is a type of amplifier in which gain is dependent on the signal level passing through it. You can set the maximum level a compressor allows to pass through, thereby causing automatic gain reduction above some predetermined signal level, also known as threshold. Punch, apparent loudness, and presence are three of the many terms used to describe the effects of compression. Compression settings will always need to be tailored to a track, if any of the audio tracks on the project feel like they have variable dynamics over the course of the whole track you must adjust the compression settings. This can be done by applying appropriate compression that will aid in making sure that the tracks all sit well with the others present. Compression works by reducing the dynamic range of audio through detecting when it exceeds your specified level or threshold and then attenuating it. Compression is used within mixing to tame dynamics, for peak limiting, parallel processing, sjidechaining and manipulating amplitude envelopes among other things. Compression has many controls that you can tailor to produce the sound you want, these are threshold which determines the level at which the compression kicks in, ratio which is the amount the level will be reduced , attack and release which determine how quickly the input signal is put down and how long it takes for the signal to return to being uncompressed respectively, knee which controls the character of the gain reduction that is applied to the the signal, and lastly make up gain which can allow you to make the track louder without encountering the issue of clipping or digital distortion.