The Chorus Project

2018-19. Individual Humanities Project supervised by Paul Chauncy.

Dissertation-based project on the science, history and cultural significance of the Chorus Effect - a pillar of the '80s' sound.

Musicology  •  Psychoacoustics  •  Music Technology  • Signal Analysis  •  Essay Writing  •  Project Management  •  Proposal Writing  • MatLab

I was invited by one of my Music Technology lecturers to undertake a ‘Humanities Project’ under their supervision. Fascinated by the sound of early indie guitar rock, I proposed and delivered a piece examining the chorus effect, and its overall significance to popular music, through scientific and cultural lenses.


The chorus effect aims to make one voice sound like multiple, by combining an audio signal with a copy of itself, in which the copy’s pitch or frequency is varied in a regular, periodic manner. This leads to a wavering, sometimes shimmering sound, that is often associated with 1980s pop and rock, thanks to the effect’s proliferation through guitar pedals (like those pictured here) and synthesiser effects units at that time.


By drawing on research in musicology, psychoacoustics, and music technology (in particular electronics), I traced the chorus’ history and development to ultimately situate it amongst the broader revolution in music creation brought about by timbral / textural processing technologies in the latter half of the 20th century.

The project was supported by various practical elements, including graphing signals passed through various real chorus effects units. I also recorded a number of demonstrative audio tracks to highlight the sonic impact of the chorus and other effects it is commonly paired with.

The first two graphs above show an ordinary sine wave, and the same sine wave once passed through a Pearl CH-02 chorus pedal. The third graph shows the sine wave passed through the pedal as the ‘mix’ knob — which controls the proportion of the original to the modulated signal — is turned up, from purely original signal to the just the modulated one.

Demo Tracks

Essay Introduction

Consider the opening chord of Prince’s ‘Purple Rain’, the eerie main riff on Nirvana’s ‘Come As You Are’, and the chiming lead guitar on The Smiths’ ’This Charming Man’. What unites these distinct and diverse pop/rock songs is a particular sonic feature present on the main electric guitar parts in each: the chorus effect. Sometimes typified as the ‘sound of the 1980s’ (Green, 2017), chorus has been used extensively over the past half century. Despite this, authors including Bennett (2016) have highlighted the lack of musicological analyses of records “in terms of … sonically discernible technological and processual interventions, as opposed to the musical make-up of … instrument performances.” (p. 4) This remains especially true for chorus. Thus, this work aims to present a thorough analysis of chorus, from a technological, psychoacoustic, musical and cultural perspective, in order to explore its importance to popular music.


Though it is possible to trace the chorus effect back to its origins, be that as a natural effect present in the human voice, a physical, acoustic feature of instruments like the piano and twelve-string guitars, a dedicated, mechanical effect in Hammond organs or even the first Bucket-Brigade-Delay effects in the 1970s, one cannot forward a single argument for chorus’ use and widespread adoption. At each stage in the effect’s history of use and development, new uses have had an ever-growing body of former applications to reference, in which the intent behind the effect’s earliest uses has often become obscured. Further, in all of this, there is the ambiguity that stems from recordists’ inability to fully express their intentions due to the limitations of language and the unavoidable presence of subconscious influences. However, through an appreciation of resonance, (as formulated by Albin Zak, 2001), and the listener’s agency to assert connections between musical works, one can establish patterns around the chorus in the resonant field of musical/recording practice and its intertwined sociocultural backdrop. From these patterns and connections, I aim to construct arguments on the most prominent reasons for the chorus’ use and their significance to popular music more broadly: primarily as an embodiment of the transformative ability afforded to recordists by (timbral) effects, which some authors have gone so far as to call “the biggest shift in Western music since the advent of musical notation” (Taylor, 2001, quoted in Bennett, 2019, p. 73), and also as a key to the development of musical sub-genres including dream-pop. In these arguments for the chorus’ use, there is nonetheless a higher-level idea that recordists seem to have generally aspired to, which is, as Albin Zak (2001) states, that “a striking sonic character adds a further dimension of sonic meaning to the pitch and rhythmic elements of the musical part, creating a comprehensive formulation of musical substance.” (p. 3)

Bennett, S. (2016) Time-based Signal Processing and Shape in Alternative Rock Recordings. Journal of the International Association for the Study of Popular Music. 6 (2). Available from: DOI 10.5429/2079-3871(2016)v6i2.2en


Bennett, S. (2019) Modern Records, Maverick Methods: Technology and Process in Popular Music Record Production 1978-2000. London, Bloomsbury Academic.


Green, T. (2017) A Decade of Shimmer: The History of BOSS Chorus Pedals From 1975 to 1985. Available from: [Accessed 1st July 2018]


Zak, AJ. (2001) The Poetics of Rock: Cutting tracks and making records. Berkeley, University of California Press.