Dynamics processors: an introduction

Dynamics processors are used to adjust the dynamic range of the sound source. The dynamic range of your sound source is basically the difference between the quietest and loudest sound. For example the dynamic range of your voice would be the difference between a soft whisper and your loudest scream.

Types of dynamics devices: the 4 main types of dynamics devices are compressors, limiters, expanders, and gates. Compressors and limiters are both typically used to decrease dynamic range, or bring the quietest and loudest signals closer together. Expanders and gates are typically used to increase dynamic range, or move the quietest and loudest signals farther apart. However, both of these statements require more description and detail, so keep reading.

Compressors and limiters, as stated previously, are both typically used to decrease the dynamic range of a signal. These two devices are very similar and have many of the same controls. Put simply, a limiter is just an “extreme” use of a compressor. However, these two devices have very different uses. A mix engineer will typically use many compressors, but will use limiters sparingly and typically only in a few specific situations. Limiters, on the other hand, are an important tool for the mastering engineer (as are compressors), and are a key ingredient for the mastering engineer to achieve the incredibly loud signals that record companies are asking for these days (but that is a discussion better addressed in another post).

Expanders and gates, as stated earlier, are both typically used to increase the dynamic range of a signal. These two devices are also very similar and have many of the same controls. Again, put simply, a gate is an “extreme” use of a downward expander. Downward expander? Where did that come from, you ask. Expanders can expand in two different ways. They can expand the dynamic range by either making the quieter sounds of the signal even quieter, or by making the louder parts of the signal even louder.

In my next post I will start discussing compressors. I have graphics and audio examples that I need to get prepared so they can be easily referenced in the post, so it may take a few days to get all of that together. Stay tuned…