## 3 Artificial Audio Effect Technologies
### Sound Recording and Reproduction Technology
Another notable example is [PERSON], who was in attendance at the Berlin performances of [PERSON] and [PERSON] and who later acknowledged the importance of their work. [PERSON]'s work _Imaginary Landscapes No. 1_ from 1939 involved playback of electronically generated sounds at different speeds [69]. Advances in technology to record audio optically on sound film, which had several advantages over disc recordings, also contributed to the diminishing interest in gramophone music at the time. As opposed to film, the 78 rpm discs used for phonographic playback had a recording limit of only 4 min. In addition, film could be spliced and cut. In the world of experimental (and popular) music, however, the magnetic tape, as developed in the 1930s by German company AEG (Allgemeine Elektrizitats-Gesellschaft) and after World War 2 by American company _Ampex_, was of greater importance. [PERSON] and [PERSON] were the driving force behind the development of the French school of early electronic music, _misique concrete_, beginning in the 1940s and the founding of the Groupe de Recherche Musicales (GRM) in Paris. Musique concrete was based mainly on manipulated recorded sound, where music was seen as a \"sequence of sound objects\". According to [PERSON] [70], these sound objects \"must be distinguished from the sound body or from the device that creates it\". This is also referred to as _acousmatic sound_, a sound that one hears without seeing the causes behind it [71]. [PERSON] describes this disassociation of sound from the sound source or context by the listener as \"reduced listening\", which can be supported by artificial manipulation of sound. Indeed, [PERSON] laid out several postulates and rules for _misique concrete_, one of them stating the need to learn how to utilise \"sound manipulating devices\", such as tape recorders, microphones, and filters. Although the term _misique concrete_ is mainly associated with compositions for tape recorders, [PERSON] also experimented with turntables in his earlier works, pioneering several audio effects. The first five _Etudes de Bruits_, premiered in 1948, contained filtered sounds (1/3 octave, low-pass, and high-pass filters) as well as mechanical reverberation of material recorded on shellac records. Moreover, sound modifications included sound transposition (variable speed playback), reverse playback, and dynamic volume envelopes [72]. The arrival of the tape recorder in the early 1950s opened up new possibilities for sound manipulation and led to the development of dedicated devices, such as the _phonogene_ based on speed variations of the playback, thus changing the pitch of the audio material. A later version of the device, the _universal phonogene_ from 1963, was capable of changing pitch independently from duration. The device was preceded by the time/pitch changer developed by [PERSON] [73] based on optical film recording and the _Temophon_ by German company _Springer_ in 1955 using magnetic tape [7]. Even earlier examples of patents based on the principle of rotating pickup systems for changing the duration of sound recordings can be found. In his review of early time stretching/pitch shifting devices, [PERSON] [74] identifies related patents filed for instance by [PERSON] and [PERSON] [75] and [PERSON] et al. [76]. [PERSON] [74] presented his own device as well, the _Audulator_, a keyboard instrument that is capable of reproducing a sound over two octaves without changing the duration. These devices were based on the principle of time-granulation. [PERSON] [73] replaced the slit through which light is projected to a photocell with a rotating cylinder with multiple slits to achieve this. In a similar fashion, the devices using magnetic tape had a rotating drum with multiple playback heads, thus picking up segments of the recording successively [76]. The pitch was controlled by the relative speed of the heads to the tape, while time stretching could be achieved by multiplicative and chop-out scanning [74].