In the 1920s, when radio broadcasting was still in its early stages, the first equalizers were created. Electro-mechanical equalizers were then used by radio engineers to selectively increase or decrease audio signal frequencies, which consisted of rows of knobs and dials for every frequency band. Their main purpose was to balance the audio signal in radio broadcasting, and the RCA 8B, which was first released in 1931, was among the first instances. Equalizers started to appear in recording studios as music recording methods advanced in the 1940s. The world’s first commercial LP vinyl record, for instance, was created in 1945 by engineer Peter Goldmark and had a 20,000 Hz high-frequency boost. An equalizer was used to achieve this boost, which contributed to setting the bar for later records.
A new generation of EQs needed to be created in the 1950s and 60s. With more accuracy and control over the audio signal, these equalization panels employed electronic circuits to boost or cut specific frequency ranges. The Pultec EQP-1A, which debuted in the 1950s, was one of the most well-known early electronic equalizers.
Parametric equalizers became popular in the 1970s and 1980s in particular. Engineers could now gain even more control over the audio signal by adjusting the bandwidth, amplitude, and center frequency of each frequency range using these EQs. When it comes to equalizers and how they are used in music production, the 1980s were a decade of invention and experimentation. In the 1980s, producers also dabbled with other kinds of EQs, such as the dynamic EQ. In the 1980s, the DBX 905 was one of the most sought-after dynamic equalizers. This device gave producers the ability to dynamically adjust a signal’s frequency response in response to the audio’s input level. This method, which is similar to how compressors operate, was used to compress the sound on specific frequency ranges, giving producers more control over the volume of sound. The production of “Like a Prayer” by Madonna and “Music for the Masses” by Depeche Mode both heavily utilized the DBX 905.
In the modern era, EQs have become increasingly popular digitally, being more easily accessible on DAWs such as FL Studio and Ableton. A particular EQ that I personally use is the parametric EQ, which enables me a lot of flexibility when it comes to adjusting frequencies. Other types of EQs include graphic, a lot easier approach to to equalization with fixed-frequency bands, and shelving, which doesn’t include frequency bands but can cut or boost sound frequencies.
Kirchner, A. (2023) AAX/au/VST audio plugins from Black Rooster Audio, Black Rooster Audio. Available at: https://blackroosteraudio.com/en/blogreader/a-brief-history-of-equalization (Accessed: 17 April 2025).