A History of Audio Engineering and Magnetic Recording Before 1943

The first stereophonic recording with two separate channels on one magnetic tape were made in 1943. This was planned and executed by members of the Reichs-Rundfunk-Gesellschaft (RRG) in Berlin. The recorder consisted of an AEG Magnetophone K7 tape transport, equipped with two-track recording and reproducing heads, two V7b recording amplifiers modified for ac-bias, and two V5 reproducing amplifiers. Three Neumann condenser microphones were used for the sound pickup.

With that technology and equipment, excellent frequency response, nonlinear distortion, and dynamic range were achieved. Approximately 200 recordings, mainly of classical music, were made at the RRG. Only five of these recordings remain in existence today — the others could not be found after World War II.

Fifty years ago consumer stereo reproducers did not exist, and only monophonic radio transmission was possible. However, playback equipment could be set up so that the stereophonic recordings could be played, for example, in hospitals. On the occasion of the fifty-year anniversary of this important step in magnetic recording, the AES 94th Convention will present and describe these historic recordings. A live playback of the recordings will take place at the end of the historical session.

In the twelve paper presentations, the authors will show the development of magnetic audio recording and storage technology to 1943, beginning in the USA and continuing with audio technology in Berlin. The authors will speak about the first principles and the resulting components of magnetic recorders, which led to astonishing results even from today’s point of view. Historical equipment, apparatus, and components are exhibited during the convention in conjunction with this session.

[From the Convention Program in the AES Journal, edited by J McKnight]

This paper reviews the history of the development of audio technology in the United States from its origins in Alexander Graham Bell’s telephone to the wartime work of the American electronics industry. It includes a comprehensive review of American contributions, including developments in electronic amplifiers, microphones, loudspeakers, and phonographic, optical, and magnetic recorders. The paper will place these technical developments in the overall context of American developments in audio engineering during this period, and will show how social and economic factors retarded the growth of magnetic recording technology in the United States.

Preprint No: 3481

The history of Berlin of the past 100 years shows a great many names, inventions, and developments in the fields of science, fine art, and technology. This also refers to audio with regard to telephone, film, disk records, radio, and television. For the electroacoustic transmission, the microphone is the first link of a long chain. This presentation addresses the contributions made in Berlin from 1880 through 1943, up to the development of this transducer. Discussed will be the simple carbon granule microphone, the Reisz microphone, the rf-condenser microphone, the kathodophone, the ribbon microphone, and the condenser microphones with dc polarization.

Preprint No: 3482

In 1908, R.V. Lieben invented the Electronic Relais, a bulb in which an electric current could be modulated by a grid electrode. Soon the new principle was improved upon. During the second decade of the century, the process of developing electron tubes for radio transmitters and receivers was amazing. Twin and triple systems connected internally in one bulb were the beginning of integrated circuits, used in amplifiers and receivers. By improving the performance stability tubes, more complex electronics problems could be solved.

Preprint No: 3483

The development of audio amplifier techniques from the beginning (for example the Lieben one-tube amplifier) to the amplifiers of the Reichsrundfunkgesellschaft (RRG V5, RRG V 7b) will be explained by specific examples. The special tasks, the basic functional principles, as well as the date and the circumstances of the applications will be explained.

Preprint No: 3484

In 1877, Werner von Siemens invented the electronic acoustic transducer based on the electrodynamic principle—according to the principle of the plunger coil generally applied today. Initially the transducer was used as a telephone receiver. With the appearance of power amplifiers around 1920, the Siemens laboratories began to manufacture a number of different designs, which eventually gave rise to the loudspeaker combination Euronor of Klangfilm GmbH in 1937. Other trend-setting loudspeakers by Berlin inventors worthy of mention include the electroacoustic Statophon by Hans Vogt, dating from 1921 and the O 15 with coaxial bass and treble chassis, by Hans Eckmiller, used at RRG Studios from 1943 onward.

Preprint No: 3485

Around the turn of the century, Berliner’s phonograph record, parallel to Edison’s cylinder, had established a firm footing all over the world. What had originally been a curiosity could be found in millions of homes. However, apart from the name “Berliner” and the fact that numerous firms were producing both cylinders and disks and players in large quantities in Berlin, the city took no part in the promotion of this new entertainment medium. It was only in the special utilization of the phonograph record as the sound carrier for the acoustic accompaniment of “living pictures” (as movies were called in their early beginnings), that original ideas began to emerge from the German capital.

Preprint No: 3486

Optical sound track recording has a history of over 100 years. A survey of the fundamental steps of progress is given. The landmarks described include: the variable-density technique by Ruhmer; the technology and techniques of the Triegon system and its importance to the following development; the foundation of the Klangfilm GmbH by Siemens and AEG; and the Eurocard-recorder and the Klarton voiceless system. The origins of the analog stereophonic optical sound are discussed.

Preprint No: 3487

In 1900, the Berlin company Mix & Genest began manufacturing magnetic sound recorders. The further development of Poulsen’s Telegraphon did not take place until tube amplifiers became available in the early 1920s. Typical Berlin recorders, all of them with information carriers made of steel, were the Vox dictating machine, the Stille SEPMAG transport, the Echophone Dailygraph, and the Lorenz Stahlton-Bandmaschine (Steeltone-Tapemachine). In 1935 the AEG Magnetophon K1 started the magnetic tape era and by introducing ac biasing in 1940 and two-channel stereophonic technology in 1943, a previously unknown reproduction quality was obtained.

Preprint No: 3488

The first official radio transmission in Germany took place in October 1923, broadcast from a small studio which was acoustically prepared on a temporary basis with horse blankets, crumpled silk paper, and curtains. For the recording, a Reiss microphone was used, as well as a VOX phonograph which irradiated the sound via a trumpet directly into the microphone. The VOX building at Postdamer Platz in Berlin was full of studios with different acoustical properties, such as the so-called Schaeffer tent. In 1931 the Broadcasting House (Haus des Rundfunks) was opened with new studios and the first large recording studio for symphony orchestras. The first microphone was that of Reiss in 1864. Together with the telephone of Graham Bell, the first acoustical transmission took place when the Eiffel Tower was completed in Paris in 1881. Recording and transmission techniques, sound absorption and sound-proofing, cinemas, and the first radio studios will be described as well as the work of the architects, artist and technicians who opened the way for the new media: radio.

Preprint No: 3521

Walter Weber (1907-1944) was one of the highly innovative engineers at the Reichs-Rundfunk-Gesellschaft (RRG), or German Broadcasting Company. Judging from today’s vantage point, his most important contribution to the development of audio technology was the implementation (not the invention) of high-frequency biasing in practice. With this single stroke, magnetic recording became the most favorable method in sound recording, both in terms of reliability and quality. Subsequently, Weber combined magnetic tape recording and stereophony, reflecting the advanced state of recording technology at RRG at the time.

Preprint No: 3522

The age, the historical and the artistic relevance, and the specific history of RRG tapes draw immediate attention to their preserved state. This paper describes these tapes within the general framework of magnetic tape preservation. In addition, the paper develops perspectives for more intensive studies into the field of preservation and rejuvenation of historical tape materials.

Preprint No: 3523

Almost exactly 50 years before this (1993) Convention, on April 6, 1943, the first 2-channel recording had been made in the SFB concert hall. This documentary recording had been lost and has now been returned to Berlin. Far more important stereophonic recordings from 1944 are Beethoven’s Piano Concerto No. 5 (Walter Gieseking) and the final movement of Bruckner’s 8th Sinfonie (Herbert von Karajan). Helmut Krueger, the former Sound Engineer will talk about the origin of these tracks as well as Hans-Ludwig Feldgen, the Sound Engineer of the first Stereophonic Live-Broadcast.

No Preprint Available