In this project I explore using a Raspberry Pi Pico to sequence the playback speed and volume gate of a tape machine using Pulse Width Modulation. 



Since the advent of the digital recording age in music technology, it has become easy to overlook the significance of musical tape in studios and commercial playback applications of the late 20th century. For over half a decade, tape was the predominant recording format (C. Mead & Miranda, 2020), within which time countless innovators expanded the boundaries of the format itself. The BBC Radiophonic Workshop in London, and IRCAM in Paris (Briscoe, 1983), among other institutions across the world in the 50’s and 60’s, were home to early pioneers, such as Delia Derbyshire, who used tape as an instrument for new musical expression. Innumerable creative techniques came out of this era, including pitch shifting (by varying playback speed), and the tape loop (The Delian Mode, 2009). These techniques provided a whole new toolset for composers to utilise in avant-garde composition, and soundtracks for audio-postproduction. The exploration of tape continued to transverse into new avenues throughout the later parts of the 20th century and was a key component of Brian Eno’s term ‘Generative Music’, with several of his works from the late 70’s using multiple tape loops to build an evolving and generative system for composition (Roquet, 2009).

Despite this wealth of musical history, the tape format as a black box instrument for musical expression (Howard & Angus, 2009), continues to thrive in the digital age (Duster, 2021). Perhaps the most distinguished works from the 21st century, are from William Basinski’s 2001, ‘The Disintegration Loops’, in which stored tape from his recordings in the 80’s where used to create loops that gradually degrade to soft noise over each repetition as a result of tape dust and age (Demers, 2017; Bogalheiro, 2018). The ‘disintegration’ of the tape is symbolic of the context that William Basinski’s found himself in whilst composing these pieces in New York City, during the terrorist attack on 9/11. Basinski’s work, also encapsulates the cultural rejection of the polished and hyper-produced characteristics of modern recording methods. Throughout the previous few decades, the influence of digital technology was refining the process of musical production, to a point where traditional tape recording was already expelled from many modern studios (C. Mead & Miranda, 2020). The term Hauntology, introduced by Mark Fisher, describes cultural trends that recall threads from previous popular culture, and subvert them into a current socio-political and aesthetic context (Fisher, 2012). As such, the ‘The Disintegration Loops’ are a significant artifact from this genre. Now 20 years on from ‘The Disintegration Loops’, tape loop culture is more prominent than it ever has been. Although the movement may be theorised as something of a rejection of the digital age (Demers, 2017), its growth as a movement is almost entirely centred on its prevalence in social media. German Ambient composer, Hainbach, documents his musical practice extensively online, with his YouTube channel regularly obtaining hundreds of thousands of viewers. His work is entirely hauntological, as he reinstates redundant test equipment, vintage synthesisers, and relics from the tape era to record ambient and generative works (Gutiérrez, 2022).  In 2020, Hainbach reimagined Basinski’s work with his own set of compositions titled ‘The Destruction Loops’ (Hainbach, 2020).

Hainbach, and other composers within the hauntological/ambient genre, often compose with cassette machines, which are usually 4 channel stand-alone recording consoles that record directly to ¼” cassette tape. The first four-channel cassette recorder was the Tascam ‘Teac Portastudio’, revealed at the 64th AES convention in New York in 1979 (Audio Engineering Society, 2022).  These, and the following range of 4-track cassette recorders developed throughout the late 20th century, were originally intended for home studio recording. However, their typically low signal to noise ratio, high levels of nonlinear harmonic distortion (Mitchell & Bennett, 2018), and susceptibility to wow and flutter (Harrison, 2019) meant that they were never utilised in many commercial productions. However, in the wake of the hauntological genre, and the cultural rejection of digital production, these characteristics have become desirable to within this field of music.  Furthermore, these devices are very easy to use, are relatively cheap and easy to find in second hand markets age (Duster, 2021), and are quite simple to modify. Therefore, over the past decade, the use of the cassette recorder in music composition has grown enormously, inspiring hobbyists and professionals to explore the medium. Additionally, the ability to modify the machines has also attracted a large population of the circuit bending community (Collins, 2020) into tape composition, wherein hardware mods such as motor speed controllers (pitch mods), tape delays (using 3 tape heads), and adding additional hardware outputs have become a distinctive element of the tape community.

The aim for this project was to expand the workflow of cassette loop composition, by incorporating techniques from the Radiophonic era, concepts from Brian Eno’s Generative Music, and  techniques explored through circuit bending. Considering that most pitch mods are static parameters, that only allow the user to set the playback to a set speed, this project aims to utilise a microcontroller and a Pulse Width Modulation circuit to vary the playback speed of the motor sequentially. This would enable composers to explore pitch sequencing in tape composition as a cross-adaptive audio effect  (Reiss & Brandtsegg, 2018). Therein, this project also aims to explore the synergy between modern digital interface design, and analogue methodologies.  The full development of the project can be found in this Instructables above, and the code can be accessed in GitHub.


The cassette community has developed a rich online collection of tutorials for developing pitch mods in 4-track cassette recorders. One of the drawbacks of this however, is that very few people interested in cassette composition have a strong electronics background. Most of the content is developed by people with experience in electronics, with the necessary equipment. Therefore, the market for tape emulation plugins, such as the Arturia ‘Tape MELLO-Fi’ (Arturia, 2022), has become quite conspicuous, and relatively saturated. One of the issues with tape emulation software, is that it does not retain a lot of the cultural markers that exist in physical tape composition. One of these markers is the cross-modal interaction that a composer experiences when composing on a tape machine (Donato, et al., 2020). The tactile interaction between the composer and the cassette machine exists in instances when the composer may adjust multiple parameters at once, such as volume sliders or effects sends – or in the simple act of splicing the tape to create a tape loop. It should be stated, however, that software does provide an obvious advantage in cross-adaptive audio techniques (Reiss & Brandtsegg, 2018), wherein automation from the DAW may be used to adjust different parameters over time. Consequently, this actually places the Pitch Sequencer in a unique marketing position. Firstly, the device has a relatively simple schematic design, and could be developed by people with minimal electronics skills, using breadboards and other prototyping techniques. However, if people are not willing to build the module themselves, then the module could be manufactured for them to purchase. This strategy was adopted by the tape composer Amulets, who manufactured a series of tape machines with a simple pitch mod for people to purchase online (Taylor, 2019).  Secondly, the sequencing function of the device is designed to enable cross-adaptive audio composition opportunities, including tempo, pitch and volume automation. These techniques have never been inherently possible in analogue tape recording, and thus this device would enable composers to explore new techniques within tape composition.



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Audio Engineering Society, 2022. AES: PRO AUDIO REFERENCE. [Online] Available at: https://www.aes.org/par/p/ [Accessed 20 04 2022].

Bogalheiro, M., 2018. Disintegration and repetition: an analysis based on William Basinski. Lusophone Journal of Cultural Studies, 5(1), pp. 293-305.

Briscoe, D., 1983. The BBC Radiophonic Workshop : the first 25 years : the inside story of providing sound and music for television and radio, 1958-1983 / remembered by Desmond Briscoe and those whose versatility and unremitting voluntary enthusiasm have made an idea a real. London: British Broadcasting Corp..

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Collins, N., 2020. Handmade Electronic Music: The art of hardware hacking. 3rd Edition ed. London: Routledge.

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Donato, B. D., Dewey, C. & Michailidis, T., 2020. Human-Sound Interaction: Towards a Human-Centred Sonic Interaction Design approach. Proceedings of the 7th International Conference on Movement and Computing, pp. 1-4.


Duster, B. D., 2021. "Cassette Culture 2.0: On how the Cassette prevails in the Digital Age, Queensland: Griffith University.

Fisher, M., 2012. What is Hauntology?. Film Quarterly, Volume 66, pp. 16-24.


Gutiérrez, N., 2022. HAINBACH. [Online] Available at: https://www.hainbachmusik.com/ [Accessed 20 04 2022].


Hainbach, 2020. Destruction Loops I​-​IV. [Sound Recording] (Hainbach).


Harrison, J., 2019. Pitch Modulation as a Creative Effect, Salford: School of Computing, Science and Engineering, University of Salford.


Howard, D. M. & Angus, J. A., 2009. Acoustics and Psychoacoustics: Fourth Edition. Oxford: Focal Press.


Mitchell, T. & Bennett, C., 2018. Characterizing the effect on linear and harmonic distortions of AC bias and input levels when recording to analog tape. New York, s.n.


Reiss, J. D. & Brandtsegg, Ø., 2018. Applications of Cross-Adaptive Audio Effects: Automatic Mixing, Live Performance and Everything in Between. Frontiers in Digital Humanities , Volume 5.


Roquet, P., 2009. Ambient Landscapes from Brian Eno to Tetsu Inoue. Journal of Popular Music Studies, 21(4), pp. 364-383.


Taylor, R., 2019. Amulets: MVS-1 CUSTOM MODIFIED, WIDE-RANGE VARIABLE SPEED CASSETTE RECORDER. [Online] Available at: http://www.amuletsmusic.com/mvs-1.html [Accessed 20 04 2022].

The Delian Mode. 2009. [Film] Directed by Kara Blake. Canada: Philtre Films .