Producing a binaural radio play for telling the history of 3D sound recording

Stefan Krebs, Luxembourg Centre for Contemporary and Digital History (C2DH)

29 October 2019


The following paper was presented in the session “Best practices in alternative (academic) publishing on media history” at the 2019 IAMHIST symposium in Dudelange.

In 1973, binaural stereo was introduced to the German public at the International Broadcasting Fair in Berlin. Based on the invention of artificial head microphones (also called dummy head or Kunstkopf microphones), binaural stereo provided facsimile sound recordings that enabled listeners, when listening with headphones, to experience the spatial acoustics of the original recording situation. During the fair, Berlin-based radio station RIAS broadcast the first binaural radio play, “Demolition”. Radio listeners and journalists praised this first binaural radio drama for its “super stereo” quality and the highest fidelity ever heard. Despite this remarkable response, German broadcasting stations were reluctant to adopt binaural stereo, and most sound engineers refused to use Kunstkopf microphones. They alluded to certain technical shortcomings of binaural stereo in general, and to the issue of available microphone models in particular. However, the rejection of binaural stereophony by the radio industry was in fact based on contemporary listening and recording practices rather than on the actual technical shortcomings of binaural stereo.

This, in brief, is the story told in the radio play “Splendour and misery of Kunstkopf stereo [in German: Glanz und Elend der Kunstkopf-Stereophonie]”, which I want to present today as an alternative approach to historical storytelling. The production of the radio play was part of a broader research project, funded by the Luxembourg National Research Fund (FNR), on the failure of binaural stereo. The project combined ideas from the history of science, media and technology with models of path dependency from innovation studies.

Before I tell you more about the radio play, let me first explain what binaural stereo is. “Binaural” simply means “with both ears”. The term emphasises that our “normal” auditory experience is shaped by the fact that we listen with two ears. Human spatial hearing largely depends on binaural listening, since our perception of the direction and distance of a sound source is shaped by tiny differences in time and intensity between the two ear signals. Binaural stereo, or 3D sound reproduction, means that a sound is recorded, transmitted and reproduced in such a way as to deliver the same auditory signals to listeners’ ears as they would have received in the original recording situation, giving them the impression of being present during the actual recording.

Binaural sound reproduction can (only) be achieved through Kunstkopf recordings and headphone reproduction. A Kunstkopf is a manikin with microphones in his ears. I say “his”, because all commercially available artificial heads are designed with the physical properties of an average male head. Artificial heads for sound recording have been well known since the 1930s, and the term “Kunstkopf” was coined by researchers at the Philips Laboratory in Eindhoven in 1939. In around 1931, researchers at Bell Telephone Laboratories in Murray Hill, New Jersey, constructed the first artificial head microphone. They used a manikin’s head and mounted microphones on the cheeks, roughly where the ears would have been. Capturing sounds with this type of microphone and reproducing them with head receivers provided what they called “true auditory perspective”. In 1934, Bell engineers J. C. Steinberg and W. B. Snow defined “true auditory perspective” as sound reproduction “which preserves the spatial relationship of the original sounds”. During the winter of 1931-32, Bell engineers Karl Hammer and W. B. Snow developed a full binaural system. It consisted of an artificial head, nicknamed Oscar, a set of amplifiers and equalisers, and 32 pairs of head receivers, which “ideally” reproduced “in a distant listener’s ears […] exact copies of the sound vibrations that would exist in his ears if he were listening directly.” Philips engineers developed another Kunstkopf in the late 1930s, but all early Kunstkopf systems suffered from the still immature state of microphone technology, for example the fact that microphones were too large to actually mount inside the ear so they were instead placed on the cheeks.

It was only in the 1960s that various research groups in Germany started to build new artificial heads. At the outset they had different research agendas and experimental set-ups: for researchers at the Heinrich Hertz Institute in Berlin and the Institute for Technical Acoustics at the Technical University of Berlin, the Kunstkopf was a technical means to investigate room acoustics, while scientists at the Third Institute of Physics at the University of Göttingen used a Kunstkopf to study human spatial hearing and engineers at the Institute for Electrical Communications Engineering at RWTH Aachen University deployed their binaural system to investigate binaural hearing aids. Artificial heads captured sounds for subjective listening tests but were also used for electro-acoustic measurements. Researchers conducted localisation experiments with music, speech, noises and pure tones, measured ear signals and impulse responses, and computed auto- and cross-correlations of ear signals and head-related transfer functions.

Different experimental versions of the Berlin Kunstkopf from Plenge, Wilkens and Kürer, 1976 (Courtesy of Ralf Kürer)

In around 1967, Georg Plenge, Henning Wilkens and Ralf Kürer from the Heinrich Hertz Institute in Berlin started to build their Kunstkopf model for acoustic research, but during their experiments they realised that binaural technology had the potential to fulfil the old high-fidelity quest of bringing the concert hall into the living room, or, as they put it, of transferring the domestic listener into the concert hall. They collaborated with the well-known microphone manufacturer Neumann and in 1973 they presented the Kunstkopf KU80, which was also used for the recording of the first binaural radio play mentioned above.

During the research project “Failure and Success of Dummy Head Recording: An Innovation History of 3D Listening”, based largely on traditional archival research and some oral history interviews, Andreas Fickers and I discussed the idea of conducting a small media archaeological experiment using old Kunstkopf technology. “Experimental media archaeology” extends the traditional discursive approach to media archaeology with hands-on experiments. Inspired by John Ellis’ ADAPT project, we also thought about reuniting historical actors with historical technology. Unfortunately, we were unable to reassemble the production crew of the first binaural radio play. So we decided instead to turn ourselves into the experimenters and to produce a binaural radio play on the history of binaural recording. During my research in the historical archive of Bavarian Broadcasting Munich, I met one of the radio editors, Werner Bleisteiner, with a special interest in Kunstkopf history. I told him about our idea for a historical re-enactment and he invited us to record it in one of the large radio play studios using old equipment from Bavarian Broadcasting.

The radio play was accompanied by a slideshow with historical images and photos from the production process that also provided English subtitles (Courtesy of Andy O’Dwyer)

The three-day recording session took place in Studio 9 of Bavarian Broadcasting in November 2016. I had written the script, Andreas agreed to speak – or rather to play one of the two main characters –, and the second protagonist was played by a professional stage actor, Stephan Wurfbaum. A former sound engineer who had made the first binaural recordings in Munich in the 1970s, together with the retired chief engineer of Neumann who developed the second Kunstkopf model in around 1980, agreed to assist us as historical and technical advisers. Werner Bleisteiner was the producer and a young sound engineer, Christian Schimmöller, was responsible for the recording and technical editing.

The storyline of the radio play “Splendour and misery of Kunstkopf stereo” is very simple. A journalist meets a media archaeologist to discuss the failure of Kunstkopf stereo in the 1970s. They meet in a recording studio where they investigate an old Kunstkopf – which we actually used for the recording. The radio play explains why 3D sound reproduction failed to revolutionise radio listening in the 1970s and, at the same time, lets listeners intuitively experience the fascinating effect of 3D sound reproduction.

The radio play was first broadcast by Luxembourgish public radio station “radio 100,7” on 11 June 2017, and we also presented it at several events for academic and non-academic audiences, including the Forum Z on “The future of storytelling in history”.

Participants at the IAMHIST symposium listening to the binaural radio play (Courtesy of Andy O’Dwyer)

I will close with some remarks on producing a radio play as a new approach to historical storytelling. First, the radio play tells a fictional story that is based on traditional historical research. It combines a very basic explanation of Kunstkopf technology with the historical narration of Kunstkopf stereo in the 1970s and interpretations of its failure to revolutionise radio listening.

Second, media history is also a history of the senses. Listeners’ subjective experience, past and present, is difficult to describe and evoke by means of a written account. Telling sound history through sound, by drawing on the “sonic immediacy” of listening to (reproduced) sound, can help generate new historical knowledge about past media practices.

Third, the advantage of a radio play is that, in using binaural technology, we can tell the history of 3D sound recording through a 3D radio play. The radio play enables listeners to experience the immersive quality of 3D sound reproduction for themselves. The binaural sound also draws listeners deeper into the storytelling and helps to evoke the historical fascination with the technology.

We do not claim that the radio play offers listeners an authentic historical listening experience, but we hope that re-enacting the experience of listening to binaural sound reproduction as in the 1970s can help to inspire their historical imagination.

You can listen to the radio play on the C2DH website, where you will also find a slideshow with English subtitles here. Please do not forget to use headphones!


Bibliography:

Krebs, S. (2019). Zwischen neuem „Hör-Gefühl“ und „Psychoterror“: Ost- und westdeutsche Diskurse zur Nutzung der Kunstkopf-Stereophonie im Hörspiel. In M. Hessler (ed.). Technikemotionen. Ferdinand Schöningh (forthcoming).

Krebs, S. (2017). The Failure of Binaural Stereo: German Sound Engineers and the Introduction of Artificial Head Microphones. ICON. Journal of the International Committee for the History of Technology 23, 113–143.

Krebs, S. (2017). „Glanz und Elend der Kunstkopf-Stereophonie“. Eine technik- und medienarchäologische Ausgrabung. In Fickers, A., Haude, R., Krebs, S. & Tschacher, W. (eds.). Jeux sans Frontières? Grenzgänge der Geschichtswissenschaft (p. 57–69). Bielefeld: transcript.


Stefan Krebs is Assistant Professor for Contemporary History at the Luxembourg Centre for Contemporary and Digital History (C2DH). He studied history, political science and philosophy at the universities Aachen and Aix-en-Provence. He received his PhD in the history of technology from RWTH Aachen University. As postdoc, Stefan Krebs worked in projects on the cultural history of car sound design (Eindhoven University of Technology); listening practices of engineers, scientists and physicians (Maastricht University); and the innovation history of Kunstkopf stereophony (University of Luxembourg).


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