RjDj

RjDj, short for Reality Jockey Ltd., was a London-based startup founded in late 2008 by Michael Breidenbruecker, a co-founder of Last.fm. Rather than operating as a conventional record label, game studio, or music-streaming service, RjDj developed a hybrid form of interactive entertainment built around what it called “reactive music.” The company’s small team created and distributed mobile applications in which software generated or transformed sound in response to the listener’s surroundings and actions. The concept drew on generative music, interactive music, augmented reality, and the event-driven design of video-game soundtracks. A reactive composition was not simply a fixed audio recording. Its application could use the sensors available in contemporary mobile devices—including the microphone, camera, accelerometer, touchscreen, and GPS—to alter musical material in real time. The listener therefore became an active participant in the performance, with the surrounding environment and the listener’s movements influencing the resulting sound. RjDj’s products were primarily distributed through Apple’s iOS platform. The company described its applications as a network through which users could obtain individual musical experiences and, in some cases, additional content. Its technology was based on Pure Data, an open-source visual programming environment for digital signal processing. RjDj also developed rjlib, an open-source library of reusable building blocks intended to help creators construct reactive music “Scenes.” This approach positioned the company as both a consumer-facing app publisher and an experimental platform for musicians, sound designers, and software artists. The RjDj catalogue included its core RjDj application as well as projects such as RjDj Shake, Rj Voyager, MusicZones, Trippy, Dimensions: The Game, Kids on DSP, and The Little Boots Reactive Remixer. It also collaborated with artists and composers from electronic, pop, experimental, and film music. Named participants associated with RjDj applications included Air, Carl Craig, Little Boots, Booka Shade, Hans Zimmer, Acid Pauli, Netsky, Chiddy Bang, Kirsty Hawkshaw, and Easy Star All-Stars. One of the best-known projects was Inception – The App, a mobile experience connected with the film Inception and involving composer Hans Zimmer. RjDj’s work represented an early attempt to treat smartphones and portable music players as responsive musical instruments rather than passive playback devices. Its applications explored how personal sensors could turn everyday spaces, bodily movement, and ambient sound into inputs for composition. The company was also notable for presenting software—not a conventional audio file—as the primary thing distributed to the listener: the software generated the musical behavior while the user supplied part of the context. The company remained small, reportedly operating with a team of four employees in London. RjDj eventually closed its website and removed its applications from circulation in 2013. As a result, the brand is now defunct, although its reactive-music experiments and open-source development concepts remain relevant to the history of mobile music applications, generative audio, and interactive media.

RjDj emerged in London in late 2008 under the corporate name Reality Jockey Ltd. Its founder, Michael Breidenbruecker, had previously been associated with Last.fm, but RjDj pursued a substantially different idea: making music behave like an interactive system. The company’s central proposition was that a mobile device could act as a musical interface, allowing software to respond to sound, motion, touch, location, and other signals from the listener’s surroundings. RjDj called the resulting form “reactive music.” The idea shared characteristics with generative and interactive music, but emphasized the user’s immediate environment as part of the composition. In a conventional recording, the sequence of sounds is fixed. In an RjDj experience, the application could analyze microphone input, respond to an accelerometer, react to touch, or incorporate other sensor data and then alter the sound in real time. The listener was consequently part of the creative process, while the application functioned as a software instrument capable of transforming the auditory environment. The company built its technology around Pure Data, or Pd, a digital signal-processing framework used for real-time audio experimentation. RjDj also made rjlib available as an open-source collection of reusable components for creating reactive music Scenes. This technical foundation enabled musicians and developers to construct interactive pieces without treating the smartphone merely as a player for prerecorded tracks. The underlying software generated musical behavior according to inputs supplied by the user, the device, and the surrounding world. RjDj distributed its work mainly through Apple’s iOS ecosystem. Its catalogue combined a core RjDj application with a succession of artist projects, experiments, remixes, and game-like experiences. Releases and associated projects included RjDj Shake, Rj Voyager, MusicZones, Trippy, Kids on DSP, Dimensions: The Game, and the Little Boots Reactive Remixer. The company also worked with artists and composers including Air, Carl Craig, Little Boots, Booka Shade, Hans Zimmer, Acid Pauli, Netsky, Chiddy Bang, Kirsty Hawkshaw, and others. Inception – The App was among the most visible projects, extending the atmosphere of the film Inception into an interactive mobile audio experience and featuring material associated with Hans Zimmer. RjDj occupied an unusual position between music publishing, software development, mobile entertainment, and experimental game design. Its work was not limited to releasing albums in app form. Instead, the company sought to establish a new distribution model in which the product was a responsive audio engine and a set of rules for musical interaction. This made each listening session potentially different, because the resulting sound depended on movement, input, and context. The business operated with a small London team of approximately four employees. There is limited publicly documented information about its financing, commercial performance, internal management, or later corporate structure. The company’s public presence ended in 2013, when its website was closed and its applications were removed from circulation. RjDj is therefore defunct, but its experiments anticipated later interest in mobile spatial audio, procedural sound, interactive music, augmented-reality experiences, and creative coding on consumer devices.

• 2013

  Public service shutdown

  [1]RjDjen.wikipedia.org

  RjDj closed its website and removed its applications from circulation, ending the brand’s publicly available service.

• 2008

  Reality Jockey Ltd. is founded

  [1]RjDjen.wikipedia.org

  Michael Breidenbruecker founded the London startup that operated under the RjDj brand and began developing responsive mobile music experiences.

• RjDj introduces reactive music applications

  [1]RjDjen.wikipedia.org

  RjDj released iOS applications in which software used mobile sensors and real-time audio processing to respond to listeners and their environments.

• RjDj develops the rjlib open-source library

  [1]RjDjen.wikipedia.org

  The company created rjlib, a collection of reusable Pure Data-based components intended to help developers and musicians build reactive music Scenes.

Experimental interactive music and mobile audio software that turns listeners, devices, and real-world surroundings into inputs for generative musical experiences.

• Reactive music platform

  RjDj

  The core RjDj mobile application presented the company’s reactive-music concept. Rather than simply playing a fixed track, it used software processing and device inputs to create an interactive sonic experience. The application served as the central consumer-facing entry point to RjDj’s network of Scenes and related musical content.

• Reactive music application

  RjDj Shake

  RjDj Shake was an application built around physical interaction with the mobile device. Its inclusion in the RjDj catalogue illustrates the company’s use of movement and handset sensors as compositional controls, turning user gestures into triggers for changing musical material.

• Film-related interactive audio application

  Inception – The App

  Inception – The App translated the world and atmosphere of the film Inception into an interactive mobile audio experience. Associated with composer Hans Zimmer, it demonstrated how RjDj’s reactive technology could be applied to a prominent entertainment property while retaining the company’s emphasis on user participation and changing sound.

• Interactive music game

  Dimensions: The Game

  Dimensions: The Game combined game-like interaction with RjDj’s responsive audio approach. It represented the overlap between mobile games and reactive music, using interactive events as a basis for changing the auditory experience rather than treating sound as a purely static accompaniment.

• Artist music application

  Little Boots – Reactive Remixer

  The Little Boots Reactive Remixer was an artist-focused application that allowed users to interact with and remix musical material. It exemplified RjDj’s collaboration model, in which established performers supplied creative content while the company provided a software framework for user-directed musical transformation.

• Reactive music application

  Kids on DSP

  Kids on DSP was described as a reactive minimal-techno project. It used RjDj’s digital signal-processing approach to turn electronic music into an interactive software experience, reflecting the company’s interest in procedural variation and real-time manipulation.

• Reactive music application

  Rj Voyager

  Rj Voyager was one of the company’s named reactive music applications and was associated with a collaboration involving Booka Shade. It explored RjDj’s idea of a mobile listening journey in which software behavior and user input shaped the musical result.

• Location-responsive audio application

  MusicZones

  MusicZones was part of RjDj’s catalogue of experimental mobile audio applications. Its name reflects the company’s broader interest in connecting music to context and environment, including the possibility of using location or changing surroundings as inputs to an interactive sonic experience.

• Experimental audio application

  Trippy

  Trippy was an RjDj mobile application built around the company’s experimental approach to responsive sound. Like other Scenes in the catalogue, it treated the phone as an instrument and used software-defined behavior to produce an evolving rather than wholly predetermined listening experience.

• 2013

  End of the RjDj public serviceStrategy

  Background

  RjDj had operated as a small startup distributing reactive music applications and related content through iOS.

  Action taken

  The company closed its website and removed its applications from circulation.

  Aftermath

  The consumer-facing RjDj service ended and the brand became defunct. No reliable public source in the supplied material explains the commercial or operational reasons for the shutdown.

  Source

1. 1RjDjen.wikipedia.org