TYPES OF COMPRESSORS – week eight
Compressors are used to reduce the dynamic range of a signal, thus reducing the difference in volume between the loudest and quietest parts of a track. There are 5 main types of audio compressors, which are VCA, FET, optical, tube and PWM.
Most commonly used are voltage controlled amplifier (VCA) compressors, which use a control signal that determines whether gain reduction is applied to the signal. They typically have all the parameters found in plug-ins, such as attack, release, threshold, ratio and knee.
FET (field effect transistor) compressors rely on transistors for gain reduction. They are incredibly fast with attack and release times to be set to almost instantaneous. With this speed, they can add distortion and colour to the signal, so they are effective when used on individual instruments rather than on a mix bus.
Optical compressors use a light-dependent resistor and a light source to determine compression. The light source inside of the compressor dims or brightens depending on the input level, so the brighter the light source, the more gain reduction is added. They are not as aggressive as FET compressors. These types of compressors are usually used for vocals to ‘glue’ everything together after adding an FET compressor, for example.
Tube compressors involve vacuum tubes designed for dynamic control that responds slower to transients compared to other types of compressors, hence they are best used for instrument or mix buses.
In addition, there is also limiting and de-essing. Limiters are compressors with a high ratio setting, being 10:1 or above. De-essers use compression to reduce specific frequencies over a certain level, such as the most common use being sharp s-sounds from vocals.
Brown, G. (2021). Audio Dynamics 101: Compressors, Limiters, Expanders, and Gates. [online] iZotope. Available at: [https://www.izotope.com/en/learn/audio-dynamics-101-compressors-limiters-expanders-and-gates.html]
McAllister, M. (2023). Types of Audio Compressors and Their Uses. [online] Produce Like A Pro. Available at: [https://producelikeapro.com/blog/types-of-audio-compressors/#:~:text=The%205%20types%20of%20audio.]
RenegadeProducer.com (n.d.). A Solid Little Introduction to Audio Compression for New and Advanced Beginner Music Producers: [online] RenegadeProducer.com. Available at: [https://www.renegadeproducer.com/audio-compression.html]