Stereo’s Life During Wartime (WWII)

With the Berlin Wall just an ugly memory, the post-Soviet political climate encouraged the Audio Engineering Society to hold its spring European Convention in Berlin for the very first time. Thus, the 94th AES Convention took place in the ultra modern multimedia facility of the International Congress Center. As with all AES conventions, the exhibition halls were full of glittering new products, and a great many technical papers were presented, with heavy emphasis on digital.

The ICC complex is across the street from Das Berliner Funkhaus, the radio station building of the RRG (Reichs-Rundfunk-Gesellschaft)—and therein lies a tale.

The Haus des Rundfunks (Broadcast House), inaugurated in January 1931, was the first building in Europe specifically designed for re cording and radio broadcasting. Part of the structure was devoted to the Grosser Sendesaal, a large hall from which symphony orchestra concerts frequently were transmitted live. After some years of development, by 1942 the RRG technicians were using the AEG/Magnetophon R22 magnetic tape recorder for recording and broadcasting. (An interesting aside: During World War II, the Allies thought the Nazis had developed a very high-speed aircraft, be cause live broadcasts of Hitler speaking in Berlin were followed a short time later by similar broadcasts from Hamburg or Munich. The Allies were not aware that they were hearing magnetic tape recordings of Hitler, ones then indistinguishable from live broadcasts!)

Now the scene shifts to early 1943. The Allies had begun to bomb Berlin, but the RRG continued to broadcast concerts from the Great Hall in Broadcast House. One of the RRG technicians, Helmut Krueger, regularly made magnetic tape recordings of these concerts. AEG had developed a 30-ips (77 cm/S) magnetic tape recorder in which high-frequency pre-magnetization (a.c. bias) was used, affording far better performance—specifically, a frequency range of 50 Hz to 10 kHz, a dynamic range of 60 dB, and distortion of 1.5%! (My old friend Jack Mullin of 3M brought one of these recorders to the U.S. and demonstrated it in San Francisco in 1945.) To gild the lily, AEG fitted a two-channel recording head to one of these machines for the RRG, thus permitting stereo recording. (These heads were originally intended to reduce distortion in monophonic taping by recording two channels in push-pull.) Krueger had access to this unit and decided to experiment with stereophonic sound. Ironically, his stereo tapes were actually bootlegs! During regular monophonic recordings with the orchestras, he ran separate signal cables from his microphones and directed them to a small input console four potentiometers and thence to the AEG stereo recorder, set up in an isolated room in Broadcast House.

Believe it or not, Krueger was using a spaced-array mike pickup—one mike to the left of the conductor, another to the right, and a third in the center—which Krueger fed to the left and right channels of the recorder. The mikes were 2 meters in front of the orchestra and 1 meter above the conductor’s head. This setup, with slight variations, was used by Bob Fine in his Mercury recordings. I used it in my Everest recordings, and Jack Renner frequently uses it today in his Telarc recordings.

By the end of the war, Krueger had made between 200 and 300 stereo tape recordings, which were stored in a bunker in Broadcast House and in several other locations. Sadly, when the Russians occupied Broadcast House, the tapes there were lost or destroyed. Of all the stereo tapes recorded by Krueger, only five are known to have survived. However, those five were the stimulus for some extraordinary activities in connection with the 94th AES Convention in Berlin.

It so happens that one of the tapes contains the Brahms Serenade for Orchestra, No. 1, in D Major, with the Greater Berlin Radio Broadcast Orchestra conducted by Walter Lutze on April 26, 1943. Thus, this year [1993] marks its golden anniversary, and in celebration the AES made arrangements to issue a CD with transfers of this recording and of two other recordings from the five surviving tapes. This historic CD was produced in cooperation with Harmonia Mundi Acoustica. Only 1,000 copies were pressed for distribution to convention attendees. (Negotiations are underway to make copies for other AES members.)

Krueger, who became chief recording engineer for the RRG, is still alive in his 88th year [ca. early 1993]. The AES has made him an Honorary Member, and during the Berlin convention he conducted a seminar on his experiences, pointing out that his stereo recordings were indeed made almost on the exact spot from which he was speaking.

But we have only scratched the surface of this fascinating story.

The first track on the AES CD is Beethoven’s Piano Concerto No. 5, “Emperor,” with pianist Walter Gieseking and Artur Rother conducting the Greater Berlin Radio Broadcast Orchestra. Gieseking was then a famous world-class pianist, and when this recording was made in 1944, he was just 49 and at the peak of his powers. Rother was relatively obscure, a talented journeyman. (It turns out that this recording has been issued on Music & Arts CD- 637, distributed by Koch International.)

The last track on the AES CD is the Finale of Bruckner’s Symphony No. 8, with Herbert von Karajan conducting the Berlin State Opera Orchestra. The recording date of September 29, 1944 is significant. By then the apocalyptic bombing of Berlin was increasing, carried out by the American Air Corps by day and with Britain’s Royal Air Force joining in the systematic destruction of the city at night. Miraculously, Broad cast House survived.

I must say, one has to wonder at and perhaps even admire all of the participants’ resolve in completing this Bruckner re cording. Amidst the Sturm und Drang of the bombing, the Allied armies advancing from the west, and the Russian juggernaut inexorably closing in on Berlin, it was clear from the vantage point of history that the war was lost. Yet here was von Karajan, giving an intense, heaven-storming performance of Bruckner’s music that revealed its beauty, its profundities, and the majesty of the stirring Finale—all the while facing a bleak and most uncertain future.

The five surviving RRG stereo tapes surfaced after taking rather tortuous journeys. Up until 1945, there was a military hospital complex in the Polish town of Kosten. Oddly enough, it also housed the RRG laboratories, whose director was Hans von Braunmuhi, co-holder with Walter Weber of the patent on high-frequency a.c. bias for magnetic recordings. Von Braunmuhl had a playback-only AEG stereo tape ma chine in his laboratory, and he often organized concert evenings for the doctors in the hospital, playing the latest stereo tapes from Broadcast House. After the German surrender, the Beethoven and Bruckner tapes were taken back to Berlin, and subsequently returned to Krueger. The other three stereo tapes were in a group of 1,500 mono tapes “liberated” by a Russian officer and taken to Moscow in 1948. They were closely guarded there in several archives, and in March 1991 they were returned intact to SFB (Sender Freies Berlin, or Free Radio Berlin). One of these three tapes contains Wagner’s Prelude to Tristan und Isolde, which was recorded at too low a level for transfer to the AES CD; each of the other two tapes is an original master of the Brahms Serenade, one of which was used for the CD. (The Beethoven and Bruckner tapes are first-generation copies and were transferred to CD without any processing.)

How do these pioneering stereo tape recordings sound on this unique CD? In a word, amazing! I was impressed by the fine clarity, relatively unobtrusive tape hiss, low distortion, wide frequency response, and surprisingly wide dynamic range, especially apparent in the contrasts of the Bruckner Finale. I would judge the Great Hall of Broadcast House to have a reverberation period of a little more than 2 seconds. Krueger had placed the orchestra and set his three mikes to afford a nice, warm ambience and good orchestral detail. There is a wide and deep soundstage to the CD, with obvious directionality and localization of instruments attesting to the authenticity of the stereophonic sound. Of course, these recordings aren’t the equal of later vintage analog stereo tapes, to say nothing of digital tapes, but they are far better than I expected. One speculates that had Krueger’s 300 stereo recordings survived the war, they ultimately would have appeared on the consumer market by the mid-1950s.

My first knowledge of Hans von Braunmuhl came when Leopold Stokowski wrote me in 1950. Stokowski said he had heard about my stereo recording activities at Magnecord and that he had worked with von Braunmuhl in Berlin. He never mentioned when they had made their stereo recordings, but it must have been in the late ‘40s. I made my first stereo recording in 1951, with Stokowski conducting the Monteverdi Vespers of 1610 at the University of Illinois. Later that year, I made stereo recordings with Stokowski and the Detroit Symphony Orchestra in the world premiere of an exotic work, “The Taking of Tung Kwan” by Jacob Avshalamov—Chinese themes and lots of percussion! Then, in 1952 Bob Fine and I made stereo recordings with Rafael Kubelik and the Chicago Symphony, Paul Paray with the Detroit Symphony, Antal Doráti leading the Minneapolis Symphony, and Howard Hanson and Frederick Fennell with the Eastman- Rochester Orchestra and Band. In 1952 I also made stereo recordings of Virgil Fox on the organ in Chicago’s Orchestra Hall and of the Don Cossack Choir.

Recently, Gramophone magazine has been publishing correspondence about early stereo tape recording. One writer noted that in October 1948, EMI made a recording of the Mendelssohn G Minor Piano Concerto in their Abbey Road Studio One, using the AEG/Magnetophon recorder. Then in 1949, EMI made a recording of the Dohnányi Suite in F, using a BTR- 1 stereo tape machine. Another writer cited Decca’s experimental stereo recording of the Mantovani Orchestra in 1953, as well as a series of recordings in 1954 with Ernest Ansermet conducting the Orchestre de la Suisse Romande. Another letter pointed out RCA’s entry into stereo recording in 1954, which launched the Living Stereo series now being reissued on CD. (Editor’s Note: See “Currents” in this issue.)

Stereo recordings were made in various places in the mid-1950s—but Helmut Krueger deserves the credit for pioneering stereo tape recording 50 years ago!

Also see this Bones Hi-Fi blog

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