# DotFX - A Programmable and Synchronized Multi-Effect Pedal based on Web Technologies

Matéo Fayet, Michel Buffa, Matis Chabanat, Benjamin Matuszewski

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Matéo Fayet, Michel Buffa, Matis Chabanat, Benjamin Matuszewski. DotFX - A Programmable and Synchronized Multi-Effect Pedal based on Web Technologies. Web Audio Conference 2025, IRCAM, Nov 2025, Paris, France. 10.5281/zenodo.17760859. hal-05388693

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Submitted on 29 Nov 2025

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Distributed under a Creative Commons Attribution 4.0 International License
# DotFX - A Programmable and Synchronized Multi-Effect Pedal based on Web Technologies

Mateo Fayet (mateo.fayet@ircam.fr) - Computer Music Designer / Ircam

Matis Chabanat (matischabanat@gmail.com) - Student / University Côte d'Azur

Michel Buffa (michel.buffa@univ-cotedazur.fr) - Full Professor / University Côte d'Azur

Benjamin Matuszewski (benjamin.matuszewski@ircam.fr) - Researcher / Ircam-STMS

## Introduction

Digital multi-effect pedals have taken on a significant role in musical creation since the miniaturization and increased performance of audio processing hardware. Indeed, having the ability to apply effects on live instruments with low latencies and increased portability (smallness, lightness, reduced amount of cables) looks like a very attractive add-on for live performances. Some manufacturers even offer the option to program your own effects (e.g. Rebel Technology's Owl Pedal).

Based on these ideas, the DotFX prototype proposes to go a step further in such development by leveraging on the possibilities offered by Web and Web Audio technologies, to propose an effect pedal that can be fully programmed and controlled from a Web interface. Additionally, leveraging on the synchronization process proposed by Lambert et al. [1], several units can be combined and automated within a shared timeline.

## Technical Overview

<figure><img src="image_2.png" /><figcaption>Figure 1 - On the left, the hardware mounted on a 3d printed socle. On the right, the remote control interface with its scripting and control windows.</figcaption></figure>

The general philosophy in building this prototype is to rely on consumer-grade hardware, Web standards and open-source software to provide a platform that is both evolutive and hopefully robust to technology changes and obsolescence. As such, the prototype is based on a Raspberry Pi nano-computer, running a regular Raspberry Pi OS, and a Hifiberry DAC+ ADC Pro sound card extended with two hybrid connectors (3 pole XLR receptacle and 1/4" jack) for input and output. The software is based on the *soundworks* framework [2] and the *node-web-audio-api* library [3] for audio processing.
Associated libraries such as *sc-components*<fnref n="1" /> and *sc-audio*<fnref n="2" /> provide the necessary tools concerning graphical user interface and basic audio digital processing operations and routing.

## Main Features

From this general architecture, we already implemented a number of features to assess the viability of the project. As such, our first prototype includes the following features. First, the audio processing is fully controlled and defined by the user through a remote scripting interface running in a browser (see Fig. 1). This scripting interface, inspired by live-coding workflows, allows us to change the behavior of the audio processing in real time without uploading any program nor restarting the process. Second, we managed to run several Web Audio Modules [4] effect plugins, written in JavaScript or cross-compiled to Web Assembly from the FAUST Domain Specific Language. Dozens of such plugins are available, implementing the most common audio FX, including some tube guitar amplifier simulators. Finally, the user defined scripts can declare parameters of interest, which allows us to generate a Web-based graphical user interface, possibly controlled itself through MIDI interfaces, that allows the user to remote control the parameters while playing.

In the short term, we will now concentrate our effort on exploring use-cases and workflows implying two or more pedals to explore the potential of the synchronization features mentioned above. For example, one can imagine synchronizing several pedals to create complex polyrhythmic patterns or to precisely schedule effect changes or automations between different musicians. Another direction will be to provide a simplified interface to generate the audio processing scripts to foster appropriation of the pedal by users without programming skills.

## Future work

From these different proofs of concept, our goal is to provide a fully working device that can support the more complex production and stage requirements, as well as to enable novel workflows in these contexts.

Hence, an important dimension of the project in the future will be to support seamless integration of the devices in different workflows to support a wide range of usage. On the one hand, the device should be usable by a musician alone on stage and without any computer. This implies that a device should be able to run in standalone mode with MIDI / USB controls. On the other hand, multiple devices could be used in very complex stage setup implying computer music designers and sound engineers, communication with heterogeneous software and devices, etc. Such setup in turn implies to support some sort of dynamic configuration of the network of pedals, OSC communications, etc.

We think the successful implementation of all these features could provide a valuable tool for many different users, providing new ways to envision stage production.

## Acknowledgments

This work has received support from the DOTS research project funded by the French National Research Agency (ANR- 22-CE33-0013-01).

<footnote n="1">¹ https://ircam-ismm.github.io/sc-components/</footnote>

<footnote n="2">² https://ircam-ismm.github.io/sc-audio/</footnote>
Bibliography

[1] Lambert, J.-P., Robaszkiewicz, S., & Schnell, N. (2016). Synchronisation for Distributed Audio Rendering over Heterogeneous Devices, in HTML5. Proceedings of the 2nd Web Audio Conference. WAC, Atlanta, US.

[2] Matuszewski, B. (2020). A Web-Based Framework for Distributed Music System Research and Creation. Journal of Audio Engineering Society, 68(10), Article 10.

[3] Matuszewski, B., & Rottier, O. (2023). The Web Audio API as a standardized interface beyond Web browsers. Journal of Audio Engineering Society, Special Issue on Fostering Creativity through Web Audio.

[4] Buffa, M., Ren, S., Campbell, O., Burns, T., Yi, S., Kleimola, J., & Larkin, O. (2022, April). Web audio modules 2.0: An open web audio plugin standard. In *Companion Proceedings of the Web Conference 2022* (pp. 364-369).

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Web Audio Conference WAC-2025, November 19–21, 2025, Paris, France. © 2025 Copyright held by the
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