The RCA 8B, introduced in 1931, is often credited as one of the earliest examples of equalization tools. It was used for broadcast and recording purposes – mostly radio. The RCA 8B is considered a passive equaliser. It used resistors, capacitors, and inductors to shape the frequency response of audio signals. Passive equalisers (developed from then on) typically didn’t allow users to control levels of specific frequencies individually. They usually had fixed frequency points where attenuation or boosting occurred
1950s Pultec EQP-1A
It’s the graphic equalisers that changed everything. They gained significant popularity and widespread use in the 1970s and 1980s providing a visual representation for adjusting the frequencies. They were also more precise than passive EQs offering independent control over each frequency band.
Before the introduction of graphic equalizers, audio processing tools tended to be expensive and primarily accessible to professional studios and engineers. However, with the advent of graphic equalizers, they became more affordable and were integrated into consumer-grade audio equipment such as home stereo systems and portable music players.
API 550A
Around the 1970s mixing engineers experimented with the use of EQ, making it the beginning of parametric EQ. While graphic equalisers provide sliders or faders to adjust preset frequency bands like bass, midrange, and treble, with parametric EQ, you can choose specific frequencies, adjust how wide the changes affect neighbouring frequencies, and control how much you boost or cut those frequencies, allowing for more detailed and tailored adjustments to the sound.
Avalon VT-747SP (combines a parametric EQ with a compressor)
As DAWs developed, digital equalisors were introduced as part of softwares or external plug-ins.
FabFilter Pro-Q
EQ is used to balance, shape, and enhance the tonal characteristics of audio, as well as change it in a creative way to suit the genre. Knowing the history and types of equalisation, one can opt for an earlier type of EQ for creative limits or aesthetics or simply know their way around analogue technology to use the best of it.
References:
Flanzbaum, Tim. “What Is the Difference between Passive and Active EQ’s.” Www.youtube.com, 14 Sept. 2020, www.youtube.com/watch?v=dK41oBJrBMk. Accessed 1 Apr. 2024.
KIRCHNER, ANDRÉ. “AAX/AU/vst Audio Plugins from Black Rooster Audio.” Black Rooster Audio, 2 May 2023, blackroosteraudio.com/en/blogreader/a-brief-history-of-equalization. Accessed 1 Apr. 2024.
Massenburg, George. “A Short History of Graphic and Parametric Equalization.” Intelligent Sound Engineering, 22 Feb. 2016, intelligentsoundengineering.wordpress.com/2016/02/22/a-short-history-of-graphic-and-parametric-equalization/. Accessed 1 Apr. 2024.