The Art of Listening: Hugo Benioff, Seismology, and Music

Victor Hugo Benioff grew up in Long Beach, California, raised by his mother alone and in poverty. His immigrant parents, Simon Benioff (1858–1942), a Russian-Jewish tailor, and a Swede, Alfrieda Georgina Benioff (1861–1939) who had worked for Simon Benioff, lived separately, and were briefly married only to avoid a child out of wedlock. For thirteen years Alfrieda sued Simon to provide support for their child, as reported in the Los Angeles Times.¹⁷ As a child Benioff learned the violin, though his mother struggled to pay for it. He was also attracted to science. The Nobel Prize winning physicist Albert A. Michelson employed him on the measurement of the speed of light.¹⁸ From 1917, Benioff augmented the family income by taking solar and stellar photographs at the Mount Wilson Observatory.¹⁹ After receiving a BA from Pomona College in 1921, Benioff worked briefly as a partner in a radio business, then switched to observations of stellar radial velocities at the Lick Observatory in 1923 and 1924. However, eager to study at Caltech, which he considered “the best school in America for physics,” he convinced the director of the Mount Wilson observatory, Walter S. Adams, to offer him a position as assistant physicist in the observatory in September 1924.²⁰

While work in scientific projects provided financial support, music and playing the violin brought a deeper personal satisfaction and a welcome balance to the scientific routine. Music was on Benioff’s mind during this period. In numerous letters to his future wife, Alice Silverman, Benioff discussed the technical difficulties of playing the violin, and reported about regular concerts with colleagues. His year-long stay at the isolated observatory gave him up to four hours a day to practice.²¹ Music, for Benioff, meant shared moments of creativity and beauty. When Alice argued that orchestra members were not creative artists, he responded, “Only a creative artist can make real music from a printed page.”²²

Benioff’s letters show his struggle during the early 1920s to fuse a scientific career with his passion for music. He expressed doubts about the rationality of science: “I found much to my regret that even science is faith and most often a blind unjustified faith. Most of the beauty and good things of life are lost in analysis.”²³ Benioff was unwilling to give up art and music for the sake of becoming a mere scientist. A solution to this internal struggle came when he switched from astronomy to seismology in 1924. Benioff’s career benefited from the emergence of Pasadena as a major worldwide center for geophysical research during the late 1920s and early 1930s.²⁴ At the instigation of the seismologist Harry Oscar Wood, and with the help of the astronomer George E. Hale, the Carnegie Institution of Washington under its president John C. Merriam agreed in 1921 to finance a long-term program for seismological research at Mount Wilson Observatory. Another push for seismological research in California came when in 1925 the Weather Bureau ceded governmental seismic monitoring to the Coast and Geodetic Survey. The Caltech Seismo Lab relocated to the San Rafael Hills in December 1926, jointly run by Carnegie and Caltech until 1937.²⁵ Caltech, under Robert Millikan, moved to promote theoretical research, established a geophysics department in the late 1920s, and offered a well-paid professorship to the mathematically trained German seismologist Beno Gutenberg, who had done pathbreaking work on the interior of the Earth. Gutenberg was joined by the physicist Charles Richter, who had finished his PhD at Caltech under Millikan in 1927 and became assistant professor in 1937.

Benioff, who suffered from disordered sleeping following nightly astronomical observations, jumped at the possibility to work in seismology. The detection of the earth’s vibrations posed technical challenges that were similar to the construction of electrical string instruments. Experience in one realm spilled over into the other. While improving seismological instruments, Benioff conceived of a new type of violin, and experimented with attaching a cone to a vibrating string, tripling the output intensity and improving the resonant quality. Obtaining unexpected, “rather startling results,” Benioff even thought about patenting his idea and about a possible backup career as a musical instrument builder in case his scientific career failed. Benioff expressed his surprise at the low level of the existing literature in acoustics, attributing it to the lack of musical skills:

To consolidate his scientific training, Benioff studied seismology and acoustics at Caltech, while working at Mount Wilson. Still, his doubts about a scientific career continued. He lamented his weakness in analysis and the difficulty of mathematical physics, and expressed admiration for his professor, Paul Epstein: “In his courses we can only sit and wonder.…During all his lectures he never uses notes of any kind—and writes down the most difficult equations steadily and fluently as though they were simple sentences.”²⁷ Benioff leaned toward a career in “experimental physics and theoretical physics of a non-mathematical character.”²⁸ For guidance he read the French physicist Henri Poincaré and invoked intuition as the “most valuable faculty a physicist can have.”²⁹ Once his professional situation stabilized, Benioff found himself again “completely absorbed” in mathematics and seismology, with no time for the violin. Still, he saw clear limitations to what science could do, and did not consider science a path to universal truth:

External reality was to be discovered rather with the senses, experience, and instruments of high sensitivity. Altogether, Benioff left little trace of his world views and beliefs. He was an atheist, showed interest in psychoanalysis (perhaps inspired by Paul Epstein), and had a penchant for solipsism, which he discussed with colleagues at Caltech. Politically, he was liberal, tolerant, and strongly antifascist and anticommunist.³¹

Benioff obtained his first permanent position as associate physicist in 1926, focusing mainly on the improvement of the existing California network of seismographs. However, Benioff went well beyond what the routine work required. Over the next ten years, by inventing instruments that became the world-wide standard and applying for patents while pursuing theoretical research relevant for the design of his instruments, he made himself indispensable.³² There was a clear division of labor: while the mathematically inclined Gutenberg and Richter focused on the analysis of data and theoretical aspects of earthquakes, Benioff built seismological instruments. The synergy of the two approaches turned Caltech into the leading institution for seismological research: to validate theoretical speculations required instruments of precision; conversely, the design of innovative instruments required theoretical underpinnings. Moreover, research funding on earthquakes increased in California after the 1925 Santa Barbara earthquake and the destructive 1933 Long Beach earthquake.³³ Benioff and his instruments were ready when this latter earthquake hit to provide data relevant not only to scientific investigations, but also to the work on structural engineering and the adaptation of building codes by the Caltech professor of structural engineering R.R. Martel.³⁴

Arthur L. Day, the chairman of the Advisory Committee on seismology for the Carnegie Institution, recognized Benioff’s talent and created an assistant research position for him in 1932–33.³⁵ Benioff earned a PhD from Caltech in 1935 and subsequently took a position as associate researcher for the Carnegie Institution. Benioff’s PhD thesis of 1935 shows his multiple contributions to seismology as a scientist, engineer, expert, and designer of instruments. Benioff’s thesis fell into three sections: first, the conception of a new instrument, the linear strain seismometer (to which I will return later in the paper); second, theoretical consideration of the destructiveness of earthquakes; and finally, a study of fault lines on the occasion of the 1933 Long Beach earthquake.³⁶ The second and third parts of the thesis showed his practical involvement in earthquake-prone Los Angeles and in California generally. Benioff aimed to give engineers “a more rational basis for design procedure” to avoid possible seismic destruction.³⁷ Previously engineers had to proceed on an empirical basis. Benioff came up with a formula that would be useful in practice, and his definition of seismic destructiveness was in use for decades.³⁸

Benioff’s rise was quick: assistant professor in 1937, associate professor in 1938, full professor in 1950. In the 1950s, he was a consultant expert for firms and numerous governmental commissions. Benioff retired in 1964. Throughout his career Benioff did little formal teaching; rather, he worked closely and informally with engineers and students in the workshop of the Seismo Lab, contributing “to the education of a generation of students from all over the world.”³⁹ These students learned by making, using, and playing his instruments, thereby becoming intimately familiar with them.⁴⁰

Benioff’s interest in innovative design went beyond science and music, and included super-lightweight bicycles, exotic kites, camera lenses, jet engines, and ultrasonic devices for cancer treatment.⁴¹ These interests also extended to architectural design. Benioff liked to spend the summers out of town, and he and his wife decided in 1936 to build a cabin at Mammoth Lakes that encapsulated key elements of Benioff’s life.⁴² Musicians of the Los Angeles Symphony who had cabins at Mammoth Lakes gave the Benioffs the idea to build one themselves; and collaborators from his laboratory at Caltech, Francis Lehner and Ralph Gilman, helped construct it to an innovative modernist design by a young architect from Los Angeles, Harwell Harris, who was influenced by Frank Lloyd Wright and Japanese architecture. Harris was known for a modernist style characterized by lightness, clear shapes, clean spaces, the harmony of natural and geometrical forms, and the use of new materials.⁴³ The architecture of the cabin mirrored Benioff’s design of seismological and musical instruments: minimalist, austere, clean, fluid, making use of the latest newly available materials, techniques, and technologies.⁴⁴ Lehner saw Benioff’s design choices as part of his overall aesthetic world view: “He was a great lover of the beautiful, whether it be in nature, instrumentation, machinery, structures, or in music or the arts. This was reflected in his every activity.”⁴⁵ Benioff’s modernist aesthetic guided his design in all domains and activities: his interest in one domain flowed into the other in a “synesthetic gyre.”⁴⁶

Music compensated for the limits of science for all of Benioff’s life.⁴⁷ Benioff was fond of the cello and was an eager classical music concert goer. He stood in lines to obtain tickets for the Boston Symphony orchestra under its conductor, Serge Koussevitzky, and accumulated a sizable record collection.⁴⁸ Music also organized the Benioffs’ social life. From the 1930s, the Benioffs regularly hosted concerts and dinners on weekends, inviting musicians from the Los Angeles Philharmonic and the University of Southern California, together with scientific colleagues, such as Beno Gutenberg and his wife Hertha, and later Leon Knopoff. Among the musicians who came were the cellists Axel Simonsen, Stephen Deák of the Los Angeles Symphony Orchestra, John Crown of the University of Southern California Thornton School of Music, the conductors Leopold Stokowski, José Iturbi, and Lukas Foss, the Grimes family, and many more.

Benioff’s first house in La Cañada had both a Steinway baby grand and a Baldwin grand piano, and was cramped with “lots of speakers and electrical equipment.”⁴⁹ In 1942, Benioff and his family moved to a house in Flintridge, with fifteen rooms and ample space for yet another Baldwin nine-foot grand piano.⁵⁰ Benioff’s daughter, Elena, recalled: “One was torn apart as he worked on ways of taking the sound off the strings and sending it through loudspeakers. I used to play for him as he adjusted and changed various attributes.”⁵¹ Paul Benioff remembered work “going on steadily.” A generous space that had previously served as a home movie theater allowed regular concerts with musicians from Los Angeles, including trios played on exclusively electrical instruments. “It sounded great.”⁵² Benioff had a fondness for Beethoven and Debussy, and also appreciated Carl Orff’s 1936 composition, Carmina Burana. But music was more than a pastime. Benioff consistently employed the latest technology to fuse the fields of music, electroacoustics, and seismology.

The transducer, which translates vibrations of whether strings or the earth, into electrical energy, was the key component of Benioff’s musical and seismological instruments. In musical instruments, the electrical vibrations were amplified and converted into musical sound with the help of loudspeakers; in seismological instruments, the electrical vibrations were amplified and converted via a galvanometer into traces on paper. The transducer incarnated and rendered possible Benioff’s work, a point to which I will return in the conclusion.

Benioff was all at once a scientist, an engineer, and an artistic designer of instruments. The field of seismology and electroacoustics from the 1920s up to the 1950s still allowed for such a triple combination of skills and knowledge in a single person.⁵³ Benioff’s contribution to seismology was twofold: first, he replaced mechanical with electromechanical seismometers; second, he devised a new type of instrument, the linear strain seismometer. For Frank Press, “simplicity, reliability, sensitivity” characterized Benioff’s instruments, which led to their adoption on a world-wide scale.⁵⁴

The disadvantage of mechanical seismometers, such as the 1920s Wood-Anderson seismometer, was that the movement of a weight during an earthquake registered directly on paper, either with a pen or by directing a light beam onto photographic paper; this limited the instrument’s sensitivity. A promising alternative was the electrodynamic seismometer, inspired by the principle of the telephone receiver, first suggested by the Russian seismologist Boris Borisovich Galitzin (Golitsyn), at the beginning of the twentieth century.⁵⁵ The key new element was the translation of the mechanical movements of the weight into an electromotive force that could then be measured and registered with the help of a mirror galvanometer. This electrodynamic system of translation was later called an electro-mechanical transducer, defined by Benioff in 1931 as “a device actuated by power from a mechanical system and supplying power to an electrical system or vice versa.”⁵⁶ Benioff adopted and systematically expanded Galitzin’s ideas. He developed the underlying mathematical theory of the instrument, selected new materials that went into its construction, and created a new design. He conceived a new vertical seismograph (to be called the variable reluctance seismograph), in which the vertical movement of a weight, a cylinder of 100 kilograms suspended by a helical spring, was translated via a transducer (which measured changes in magnetic reluctance) to a galvanometer, a design that surpassed the Wood-Anderson seismometer in sensitivity. Because it measured near, distant, and deep earthquakes, it was useful for studies of the Earth’s interior and rapidly became the worldwide standard in observatories.⁵⁷

Benioff’s second revolution in the design of seismographs was the strain seismometer whose central principle was no longer to have a pendular instrument with a moving weight that traced the vibratory movements of the earth, but rather to measure variations in the distance between two points on the ground.⁵⁸ Benioff’s instrument was elegant in its simplicity. The basic principles were quite straightforward: Seismic waves led to variations in the distance between two piers, separated by 24 meters (Fig. 1). Benioff built an iron rod that was fastened to one pier and ended in a close gap at the other. Minute changes in the gap could be detected by a transducer, which allowed magnification of 1,000,000, making the instrument “more sensitive to displacements than a Michelson interferometer.”⁵⁹ The original instrument was located in the basement of the laboratory in the San Rafael Hills, with piers firmly fixed to the granite underneath the Laboratory and cemented in with concrete. The simple design encountered numerous difficulties, both practical and theoretical, that Benioff tackled over decades, such as the quality of the materials used (iron was ultimately replaced by quartz), problems of temperature change (partly solved with the use of asbestos), the delicate suspension of the rod, and the design of the transducer. Theoretical problems arose in the instrument’s overall conception, in which Benioff also profited from the help of Paul Epstein. Benioff pointed to several significant advantages of his instrument: magnification of 80,000, instead of 3,000 with the Wood-Anderson seismometer, higher flexibility of use, constructional simplicity, and absence of response to earth tilt.

Transducers also formed a central element in Benioff’s design of musical instruments, as evidenced in two patents filed in 1938.⁶⁰ The first patent was for a stringed musical instrument, such as a violin or cello. Benioff’s central idea was to build an uncomplicated instrument, whose bridge became a part of the transducer to avoid “uncontrollable or troublesome vibrations of multiple parts.” It used a piezoelectrical crystal transducer cemented directly to the surface of the bridge. Due to the vibrations of the strings, the crystal was distorted and strained in extension and compression, resulting in electrical charges proportional to the bending of the bridge. This solution had the advantage over electrostatic and electromagnetic mechanisms in its “simplicity and high sensitivity.” Benioff pointed out that the usual sound box was missing, and that “the box or a frame representing it may be desirable from the standpoint of appearance, or from the standpoint of the performer who is accustomed to the physical form and ‘feel’ of the standard instrument.”⁶¹ The second patent made use of electromagnetic transduction of the energy of the string vibrations into electrical vibrations. Here, Benioff opted for an electrically conductive string vibrating in the field of a permanent magnetic block. Again, Benioff aimed at a practical solution, while taking care that “all overtones within the desired range of the instrument” would be transduced. Benioff included a correction for the higher overtones, which tended to be dominant in his construction. He also proposed different solutions for the location of the transducer for violin and cello than for harp and piano.⁶² In this work Benioff was aided by musicians, like the cellist Axel Simonsen.

A high point of Benioff’s work on electric string instruments was a concert that took place at Caltech on 12 June 1938.⁶³ It was unusual in that two of the three instruments, the violin and the cello, were electric. The artists were the violinist Peter Meremblum, the cellist Nicholas Ochi-Albi, a member of the Los Angeles Philharmonic Orchestra, and the pianist Emmanuel Bay, a member of the faculty of the Music School of the University of Southern California. The “experimental recital” took place at Culbertson Hall in front of 300 people, introduced by Caltech’s president, Robert Millikan.⁶⁴

The concert, with music ranging from Bach to Beethoven to Tchaikovsky, attracted attention nationwide.⁶⁵ Analogies between music and seismology were abundant in the newspapers: “Quake Inspired Violin Invention,” wrote the New York Times, and the Los Angeles Times coined the term “seismographic fiddle,” where “the bow plays the role of the agitated crust of the earth, while the st[r]ings take the place of the earthquake recorder’s pendulum.”⁶⁶ Although Benioff’s electric violin had perhaps not quite outdone a Stradivarius, as claimed in a LAT headline, it had nevertheless “astounded musicians by the depth, volume and clarity of its tones”; they judged the instrument as “superior in tone to the orthodox counterparts.”⁶⁷ There were also a few critical voices. The music critic of the LAT observed that the violin did not sound “so beautiful” in the higher notes.⁶⁸ Since the sound was electrically amplified by loudspeakers from the audio-electronic firm Lansing, these instruments could also more easily fill large concert halls—although this led some musicians to fear that the new technology would reduce the number of jobs in orchestras.⁶⁹ Benioff, himself, seemed “somewhat apologetic about his inventions” in his detailed technical explanations at the concert and remarked that “much experimental work was still to be done.”⁷⁰ In 1938, Benioff’s musical instruments seemed to promise a viable alternative to orthodox instruments. At Caltech, there was even talk of creating an institute dedicated to research into electrical instruments, coherent with the general enthusiasm for electronic experimentation in music during the 1920s and 1930s.⁷¹

However, during WWII, with Benioff working for the Submarine Signal Company, the momentum ceased. When another concert with an electrical cello took place in 1946, at the Southern California School of Music, with cellist Stephen Deák and the pianist Margaret Shanklin, the reception was much less enthusiastic. Time called the cello a “gadget” and “a queer contraption shaped somewhat like a pneumatic drill” (see Fig. 2). It also regretted its considerable weight and the need for enough “amplifying equipment to load a small truck.”⁷² Indeed, the set-up required three loudspeakers for the different frequencies. Despite the minimalistic technology that had gone into the instrument itself, the musician depended on large loudspeakers and a reliable power source during a performance.

The LAT also complained that the instrument failed “to transmit the player’s individuality of style” due to a certain rigidity in string tone and lack of control in diminuendo, and suggested that, like the Theremin, the instrument might best be used in modern works or film scores.⁷³ Benioff himself pointed to his instrument’s qualities: not only could it produce greatly enhanced sound, it also had the advantage that the “timbre is more nearly uniform throughout the playing range.” Nevertheless, Benioff added prudently that “the electro-cello should be considered an instrument in its own right rather than merely an augmented or modified cello.”⁷⁴ But that also meant that classical music continued to be played on traditional instruments, with no scores for electric violins or cellos available. In the 1930s and 1940s, these instruments, contrary to the electric guitar, failed to find a market and a wider audience. By 1946, the original enthusiasm had subsided, as the technological imperfections and inconveniences endured and could not be overcome in the short term. Benioff himself, not interested in building instruments that did not achieve his high standard, now focused exclusively on a more promising line of work, the construction of an electric grand piano, which would occupy him for more than two decades. However, I will first address Benioff’s daily practice in his workshop at the Seismological Laboratory.

Seismology and music merged not only in the transducer, but in a variety of other ways in the daily practice in Benioff’s private workshop and at the workshop of the Seismo Lab.⁷⁵ This work refined listening to earthquakes: with more sensitive instruments, more vibrations were detectable, challenging the observer to separate signal from noise.

Progress reports and other publications provide insight into daily practices. During the 1920s and 1930s, these concerned the installation, maintenance, and improvement of the instruments within the California Institute network of auxiliary seismological stations, which included the development of a radio timing method, the design of a precise low-power seismograph drum drive (with a new motor) for seismographic recording, and the switch from coil-magnet transducers to large variable reluctance transducers. During WWII, the workshop facilities were used for research on underwater listening and ranging devices on behalf of the Submarine Signal Company in Boston, leading to a situation where seismological “instrument design and construction are in abeyance.”⁷⁶ Altogether, Benioff filed for more than fifty patents for the Submarine Signal Company during the 1940s.⁷⁷ Finally, during the 1950s and early 1960s, Benioff’s group made the switch from iron water pipes to quartz pipes in the strain seismometer, and developed instruments for seismic prospecting for the mining industry. The group also conceived alternative recording devices (films) to replace the heavy and bulky paper drums, participated in military projects (such as the Palomar microseism project and the network of seismological stations as part of the VELA program to detect and monitor underground nuclear tests on a world-wide scale), and developed a lunar seismograph as part of the Ranger project. The workshop was in constant contact with other laboratories and observatories as well as firms throughout the world, and there was intense competition, especially with commercial instruments, often becoming “obsolete almost overnight.”⁷⁸

Benioff’s doctoral student, Cinna Lomnitz, recalled: “Eventually an array of homegrown high-tech industries sprang up in California, and many of them originated on Benioff’s desk at Caltech.”⁷⁹ Benioff’s closest collaborators, who stayed with him for decades, were design engineer Francis E. Lehner and research technician Ralph E. Gilman, who founded the firms Lehner & Griffith and Gilman Scientific Instrument that produced instruments commercially.⁸⁰ From 1950, Benioff cooperated with the industrial research laboratory of the Geotechnical Corporation in Dallas, working on geophysics, seismic detection networks for the military (especially for nuclear testing and detection), and seismic prospecting under the direction of the geophysicists Roland F. Beers and William B. Heroy.⁸¹

The skills and knowledge acquired in the workshop exemplify the rise of professional auditory and detection expertise from the 1920s on.⁸² For example, Benioff worked on the mechanisms of the paper drums, which recorded seismic vibrations continuously in graphic form. Only a perfectly regular movement of these drums would guarantee reliable measurements. To stay with musical metaphors: they needed to turn in perfect rhythmic regularity to render the score faithfully, like phonographs, gramophones, or the player piano.⁸³ Benioff’s tacit and embodied knowledge also showed when he used musical instruments or parts of them in his seismological instruments: piano wires suspended the long tubes of his strain seismometers, and a tuning fork served to judge the length and thus the quality of the quartz tubes of the strain seismometer: “Each length of tubing was tuned separately by hitting it with a tuning fork. When all tubes gave the same sound, they were cemented together.”⁸⁴ Listening served to standardize the individual parts, to avoid malfunctions, and “to increase embodied interaction with the instrument.”⁸⁵

In his obituary, Frank Press stressed Benioff’s “broad knowledge of the engineering properties of materials,” important for eliminating disturbances such as the temperature dependence of springs in the vertical seismometer, or varying heat coefficients in different materials.⁸⁶ For example, when Benioff replaced the iron tubes in his strain seismometer with fused-quartz tubes, he took care to choose a substance with the same heat coefficient, cesium carbonate, to connect them.⁸⁷ Benioff’s engineering knowledge of material properties is also reflected in his studies of the creep behavior of rocks, a crucial part of his theoretical studies on global tectonics and earthquake mechanism.⁸⁸ Benioff familiarized geophysicists with the equations used for nonelastic processes in technical rheology.⁸⁹ As part of this work, Benioff compared the strain build-up and release during earthquakes to the production of sound within the bowed-string cycle, in analogy to the physics of the violin.⁹⁰ However, altogether it is rather unusual that Benioff reasoned explicitly in terms of analogy between the two fields of music and seismology. Such an analogy was self-evident for Benioff: music and seismology faced identical types of problems, evidenced in everyday laboratory practice.

The detection of previously undetectable vibrations was Benioff’s particular passion. In the early 1950s, his strain seismometer was “able to observe strains of the order of one part in 100 million…a one-inch squeeze between the U.S. east and west coasts.”⁹¹ A few years later it was even able to record “1/16th of an inch.”⁹² Having reduced the “inherent noise” in his instruments, however, this achievement caused new problems: the instruments registered unwelcome and previously unknown “unrest” that had then to be studied to provide “clues to the design” of improved instruments of yet “higher sensitivity and greater precision.”⁹³ Two things become apparent: first, a never-ending reflexive cycle between diagnostic and exploratory listening, which produces knowledge about both the instrument itself and the world outside; and second, Benioff uses terms derived from listening, such as “noise,” and extends their use from acoustics and audible phenomena to electroacoustics and inaudible phenomena.⁹⁴

Seismological recordings reflected a whole range of vibrations beyond those of the instrument itself: first of all, regular microseismic events, such as the nearby ocean surf that appeared in the records roughly every six seconds.⁹⁵ For Benioff the ocean surf did not count as noise, since nothing could be done about it. Then sunrises and storms showed up in the records, which also set the earth vibrating. Finally, there was the rapidly growing city of Los Angeles, with its traffic and industry. Here, the laboratory identified previously unknown sources of noise, such as heavy machinery and “compressors in an ice plant on the other side of town.”⁹⁶ Humans were another source of disturbance, whether their footsteps in the building where the instrument was located, or in a car parked at night close to the institute.⁹⁷ The seismograms revealed all these activities in the city of Los Angeles.⁹⁸ Benioff’s seismological instruments also detected the 1945 Trinity nuclear explosion in New Mexico, as well as the 1946 underwater Bikini-Baker explosion 7,000 to 8,000 km away.⁹⁹

In the end, exactly because of its high sensitivity, the strain instrument in the San Rafael hills of Pasadena turned out to be more or less useless—at least during the day.¹⁰⁰ To avoid human interference and “local noise,” a new strain instrument was installed in early 1952, further away from Los Angeles, in a tunnel of the Los Angeles Flood Control district near the Big Dalton Reservoir.¹⁰¹ This also kept annual temperature variations to less than 1°C. Later in the 1950s, another strain seismometer was installed in a tunnel near Isabella, 28 miles north of Pasadena.¹⁰² This tunnel had the additional advantage of being 100 meters below the surface, so that the differences between cloudy and sunny days that had shown up in the Dalton tunnel strain meter no longer registered. Finally, the best records were obtained by a strain seismometer installed during the International Geophysical Year 1957–58 deep into the mountains at Naña, Peru, which “proved exceedingly dry and afforded one of the quietest sites ever occupied.”¹⁰³ Based on his sonic expertise, Benioff chose the sites most suited for listening, which turned out to be further and further away from the original laboratory at Caltech.

In 1951, Benioff also worked on the audification of earthquakes and designed a seismic tape recorder.¹⁰⁴ In order to move the low frequencies of earthquakes into the audible range, the original tape recordings were accelerated 600 times through a playback mechanism. Listening to these was supposed to provide information about the energy and energy distribution of earthquakes.¹⁰⁵ Although apparently of limited scientific value and never going beyond a pilot project, these tapes nevertheless found their way onto an LP record released by Emory D. Cook of Cook Laboratories with the title Out of this World.¹⁰⁶ An article in the New York Times advertised them as “vinyl for Atom Age entertainment”:

The tape recordings and the disk attracted wide attention. Charles Richter was fascinated by this “spectacular recent development,…which brings the earthquake frequencies up into the audio range, so that one may in a certain sense ‘hear’ the earthquake.”¹⁰⁸ Benioff played the underground sounds regularly to visiting seismologists, on whom they left a strong impression. The Danish seismologist Inge Lehmann recalled in a letter to Benioff “with what pleasure you played off from tape some earthquakes that rumbled and thundered and made me marvel.”¹⁰⁹ Sales of such kind of otherworldly LPs found a larger public, attracted to the “auditory sublime” of frighteningly compelling sounds.¹¹⁰

However, Benioff’s ambitions to listen to the vibrations of the earth went beyond just taping earthquakes. In 1952, his strain seismometers recorded an earthquake in Kamchatka at a magnitude of 9.0 on the Richter scale. As these instruments recorded extremely low frequencies, Benioff went through the recordings and started to look for patterns indicating the free oscillations of the earth, the natural frequencies of the globe. This work inspired the theoretical physicist Chaim Pekeris to carry out “fearsome sets of calculations on the Earth’s natural long-period oscillations.”¹¹¹ By the late 1950s, more sensitive strain seismometers had the potential to register these periods, given a strong enough stimulus. The Chilean earthquake in February 1960, 9.5 on the Richter scale, still to date the strongest earthquake ever recorded, provided the test of the theoretical predictions. Frank Press used his contacts at Bell Labs to make sure that doctoral student Stewart Smith got “unlimited access to computing on…IBM 704 and 709 systems” at the military’s Sandia Laboratories in Albuquerque, crucial to speeding up the analysis of the seismograms, given the limited computer facilities at Caltech.¹¹² And, indeed, Benioff had the satisfaction of seeing that a computer analysis of recordings with his strain seismometers indicated a split spectral peak with periods of 54.7 and 53.1 minutes, confirming theoretical predictions of a period of 53.7 minutes.¹¹³ Other research groups using different instruments obtained similar results, to great excitement within the scientific community and the larger public.

For Benioff “the whole earth rang out like a bell,” a metaphor equating terrestrial vibrations with audible musical sound.¹¹⁴ Stewart Smith extended it when he remarked that Benioff could finally hear the “music of the earth—its natural tones.”¹¹⁵ These sublime musical metaphors translated scientific work for a larger audience.

Benioff not only listened to natural tones, he also aimed to produce tones. In the early 1940s he became an expert consultant for the Baldwin company for its project of an electric grand piano. Benioff strived to reproduce the pure sound of a traditional grand piano. In seismology, the natural vibrations of the earth, its pure tones, had to be recorded by an instrument of such sensitivity that they could afterwards be analytically identified within the noisy spectrum of an earthquake. In music, the vibrations of the electric piano had to be produced free of disturbing vibrations. In both cases Benioff faced the same task: to build instruments that avoided as much as possible noise caused by the instrument itself.

The 1938 concert with Benioff’s electric string instruments attracted the attention of the head of the Baldwin Piano Company, Lucien Wulsin II, who saw a promising market for electric musical instruments. Baldwin instruments were the bestselling pianos in the United States, and the company employed several thousand people across the country.¹¹⁶ Baldwin began building electrical organs during the 1930s. Its engineer and research director, Winston E. Cock, patented an electric organ in 1941 that was commercialized after the war.¹¹⁷ However, Cock left in late 1941 for Bell Telephone Laboratories. When the United States entered WWII, Baldwin shifted toward war production, including airplane components and top-secret proximity fuzes, relying on Benioff’s experience in building transducers.¹¹⁸ Benioff stepped in as an expert for Baldwin to create a first-class electrical grand piano that could compete with a traditional Steinway grand. This work as a sonic expert was well paid; Benioff earned double his Caltech salary on a project in which he was keenly interested.¹¹⁹

In November 1941, Benioff filed a first patent for Baldwin, a transducer for stringed musical instruments, particularly the piano. The projected piano was largely identical to a conventional instrument, but lacked a soundboard. Benioff designed a transducer that would not entail “residual or direct mechanical sound” caused by the transfer of string vibrations to the framework of the piano, in order to achieve the “beauty of the tones electrically produced by the instrument.”¹²⁰ Benioff’s attention to the listener’s aesthetic experience showed up even in the sober technical description of a patent.

Benioff did not pursue this project alone for long, but soon found a committed collaborator, the pianist Rosalyn Tureck. In the late 1930s, the young Tureck, who had made her name in New York performing Bach on modern instruments, passed through Pasadena and gave three well-received concerts at the Athenaeum, Caltech’s faculty club.¹²¹ Benioff and Tureck met on this occasion, and for the next two decades, coming from opposite directions, they worked closely together on perfecting an electrical grand piano. Benioff’s passion for music was matched by Tureck’s attraction to science and technology. Throughout her career, Tureck was open to technological innovation and new instruments. As a teenager, she had studied with Russian engineer and musician Léon Theremin in New York, and performed in 1932 on his instrument, the Theremin, in Carnegie Hall.¹²² Further, Tureck regularly met with scientists, such as Isidor Rabi and Theodosius Dobzhansky, during the 1930s in New York at weekly Saturday dinner parties. Indeed, Tureck regarded conversations with scientists as more interesting than that with fellow musicians.¹²³

In a 1988 interview, Tureck explained her interest in science. As a pianist, she was first and foremost interested in form. Exploring the structure of music was similar to what scientists did when studying matter and energy: “I have found that the concepts with which scientists are engaged and the concepts that emerge from the evolution of experimentation, are concepts I have also been thinking about.”¹²⁴ As a pianist she saw her task as communicating this structure by developing a technique and subsequently a style. Given Tureck’s focus on the structure of music, whether to play on historical or contemporary instruments was for her a secondary, and ultimately irrelevant, consideration. In her career, she played clavichords, harpsichords, pianos, Theremins, and Moog synthesizers.

At Caltech, Tureck found an open and curious scientific community, many members having interest in music. She stayed with the physicist Paul Epstein, met J. Robert Oppenheimer at Epstein’s home, and enjoyed friendships with several Caltech professors.¹²⁵ Tureck delighted in challenging Caltech’s scientists. At the occasion of a concert in Pasadena, Tureck was the special guest to Caltech’s Stammtisch, where professors and their spouses met with a guest from outside Caltech over dinner, followed by discussion that began with a question to the guest. Tureck was asked by astrophysicist Richard C. Tolman, “Did I believe that it was possible to obtain quality in piano tone, or was it just a matter of quantity?”¹²⁶ Tureck argued that playing a tone was not simply an issue of putting weight on the key, and that she was able to create different qualities and different textures by controlling the hammer by her varying technique. She then convinced the skeptical scientists by a demonstration at the piano.¹²⁷

Benioff and his wife Alice were habitués of the Stammtisch, and Tureck described her first meeting with Hugo Benioff fondly: “Our rapport was immediate and spontaneous…He had an enthusiastic supporter in me, and we became lifelong friends.”¹²⁸ For the next two decades Tureck was a regular friend and guest of the Benioffs, once staying for two months in the summer. Tureck recounted: “Through more than twenty years I was privy to his [Benioff’s] problems of tone qualities and keyboard action, his varied experiments and solutions, and time and again I was his guinea pig by playing every conceivable kind of music on this instrument.”¹²⁹

What drove their common project of an electric grand piano? First, there was the expectation that the electric piano could ultimately compete with “most beautiful and varied piano tone” of the existing traditional grand piano. For Tureck, playing on such an instrument would possibly allow for a new quality of listening to music, especially Bach. There was also hope that the electric piano could possibly remedy some the deficiencies of the traditional grand piano and achieve “richer sonorities” in the higher and lower frequencies.¹³⁰ Second, an electric grand piano could more easily compete in volume with the full orchestra in the increasingly larger concert halls built in the first half of the twentieth century. Tureck’s hope was that the new instrument might also inspire new compositions. The electric grand piano was not a “gimmick or a fad, but to give us a superior instrument with new potentials in the fields of performing and composing,” in contrast to the suggestion made to Benioff and Tureck by conductor Leopold Stokowski (now in Hollywood after stepping down from the podium of the Philadelphia Orchestra) that they develop an electric gong.¹³¹ Third, in the context of a rapidly expanding market for phonograph records and the emergence of the LP in the late 1940s, there was also the expectation that an electric piano would improve the quality of recordings of classical music, profiting from Benioff’s expertise in recording vibrations. Finally, there was the plan to build a piano that required no tuning. This would allow a much broader distribution of pianos across the country, as expert tuners, difficult to get in the remote countryside, would no longer be needed.¹³² Here Benioff’s hope chimed with Baldwin’s commercial interests.

When Tureck first met Benioff, he had only succeeded in producing the sound of a single note, middle C. Benioff and Tureck set the bar high, wishing to build a “high-quality concert piano that would be the equal of the best Steinway concert grand,” and to achieve “piano’s highest artistic standard of the action’s sensitivity and its quality of tone.”¹³³ Benioff and Tureck aimed for “pure piano tone.” By this they meant first to overcome the electronic sound. Tureck regarded Benioff’s electrical cello as superior to the Theremin because it did not have the “cold impersonal tones” of electronic instruments. Another challenge was the dampening of sound, because “the tones slithered from one to another.”¹³⁴ Tureck was the only pianist among several to test the piano who had the patience and skill to adapt to Benioff’s sustain pedal, which was different from a conventional acoustic piano.

A prototype of an electric grand piano was ready in May, 1953. In Benioff’s house the experimental grand piano was placed between two grand pianos, a Baldwin and a Steinway, and Benioff moved “directly to one or another as he worked and listened for differences in qualities of sound.”¹³⁵ In 1959, Benioff filed for a patent on behalf of the Baldwin Company, granted three years later (Fig. 3).

The 1962 patent gives an idea of the uphill struggle to imitate the sound of a conventional grand piano on the electric grand piano. While Benioff wished to build a grand piano that could “fill a large auditorium,” and “comport with the volume of a symphony orchestra,” he also conceived that it could be used with earphones, requiring a “virtual silencing of the instrument,” another promise of large commercial significance: a market for a piano that could be played at home without disturbing the neighbors.¹³⁶

In Benioff’s electric piano, which used traditional action keys and strings, the sounding board and its bridge had been removed, and a transducer translated the mechanical vibrations of the strings into electrical oscillations. The patent lists the persisting challenges for building an electric piano. “The tonal and percussive effects of the tones produced electrically [were]…disturbingly unlike the expected piano tunes.” Variations in the size and shape of the frame, number and tension of the strings, number and positions of the pick-up devices, had so far never led to “achieving true piano tonality.” True piano tonality meant imitation of the damping effects of a conventional piano, avoidance of the longitudinal vibrations of the strings, which produced an “unpleasant roughness of the tones,” and “minimizing the transmissions of the vibrations of a struck string to adjacent strings mechanically,” which “detracts from the tonal quality of the instrument.” Benioff came up with a specific arrangement of the transducer with a cantilever, which damped the vibrations of the strings similarly to a conventional piano. Furthermore, to avoid transmission of vibrations, he experimented with a number of materials and mounted the piezo-electrical crystal into a particularly resilient material, using the trademark product, Audioid.

Each piano key and tone had its own transducer. To avoid vibrations in adjacent strings, Benioff also arranged the piezo-electric crystals alternately with respect to their polarity.¹³⁷ It was clear that when Benioff filed for the patent, the piano was not yet ready, even after some twenty years of work. The patent filing of 1959 was Benioff’s last written effort on behalf of an electric piano. When in the early 1960s Benioff moved to a smaller house, work continued in a warehouse on Foothill Boulevard. At that time, John Crown of University of Southern California Thornton School of Music tried the piano, and the seismologist Leon Knopoff played a “ceramic grand piano.”¹³⁸ Many problems remained, particularly with respect to an additional set of pedals, whose use posed problems for many pianists.

In 1961, Lucien Wulsin II, who had enthusiastically supported Benioff, handed presidency of the Baldwin Company to his son. The new management no longer deemed a high-class electric grand piano a viable commercial proposition. After his own retirement in 1964, Benioff followed developments at the company from a distance, visiting Baldwin only once or twice.¹³⁹ The development of the grand piano went in different directions, as Baldwin engineers “didn’t think they could finish it the way Hugo had intended.”¹⁴⁰ There was no public performance of the electric grand piano during Benioff’s lifetime. Neither Benioff nor Tureck thought that the electric grand piano was yet ready. In the end, none of Benioff’s electric musical instruments came to play a lasting role in concerts or compositions; the available technology turned out to be cumbersome for practical use and too tedious to be handled by the performer.

Benioff did not live to see the only public performance of the Baldwin electric concert grand piano, in 1969 in New York. Lorin Hollander played a program of Bach, Prokofiev, Ravel, Debussy, Schubert, and his own toccata, “Up against the Wall,” at the Fillmore East, “the mecca for rock performers and fans.” The audience was “mostly young, but heavily infiltrated by Uptown hippies and music-business people.”¹⁴¹ Hollander broke with the ritual of classic performances, dressed informally, addressed and chatted with the audience in between pieces, and expressed “his feelings about Vietnam and Biafra.”¹⁴² Though the concert did “not represent Mr Hollander at his best in terms of conventional piano-playing and music-making,” the public was “violently enthusiastic.”¹⁴³

Rosalyn Tureck, who attended the 1969 concert, thought that the piano was “wonderful,” but expressed her frustration with the focus on volume instead of quality of sound. She regretted that Benioff’s name had not been mentioned by Baldwin on that occasion. She recalled “that Hugo and I used to talk so much about its subtlety…its capacity for the really important artistic sounds.”¹⁴⁴ The piano was now advertised as being suited to large outdoor venues, like the Hollywood Bowl or Tanglewood, where it could “successfully compete with the modern orchestra.”¹⁴⁵ In the end, Baldwin abandoned the project. The chief engineer, Daniel W. Martin, told Tureck that due to administrative decisions the work on the piano had not been completed.¹⁴⁶

In inventing a new musical instrument, Benioff had not pursued revolutionary change, but rather had aimed to overcome the deficiencies of traditional instruments, to bring musical performances or recordings to a still more satisfying level for the listener. For him, in seismology as in music, the score was already there, but had to be (dis)played to audible perfection for both study and enjoyment. He showed no interest in musical composition.¹⁴⁷ Modern composers like Arnold Schönberg or John Cage, who also lived in Los Angeles, had no place in Benioff’s music library or repertoire.¹⁴⁸ Contemporary music, in the line of Schönberg’s twelve-tone compositions, broke with Benioff’s preference for tonal music; the abstract, mathematical principles governing these did not appeal to him. The avant-garde music of the 1950s, with its use of the piano as a percussion instrument and its exploration of electronic sounds, as exemplified by electronic music in Germany or by Edgar Varèse in the United States, went in opposite directions from Benioff’s search for the pure tone of the traditional concert grand.¹⁴⁹

However, it would be wrong to assume that Benioff was ignorant of the musical avant-garde. Given her sometimes month-long stays at Benioff’s house, Rosalyn Tureck probably shared her enthusiasm about contemporary composition and performances with Benioff. Although Tureck had revolutionized Bach performance, she also played music by Aaron Copland, Roger Sessions, and Igor Stravinsky, and she encouraged modern composers by organizing concerts at her New York home. Moreover, for several years Tureck taught at the Music Academy of the West, and where she followed Schönberg’s composition courses.¹⁵⁰ Benioff may have distanced himself from the musical avant-garde, but up to the 1950s he was at the top of a scientific and technical avant-garde whose achievements also promised to change music in one way or another.¹⁵¹

In 1968, Ray McConnell, the executive editor of the Pasadena Star News, wrote a passionate obituary for his friend, Hugo Benioff:

McConnell’s highly personal éloge aptly evokes three key aspects of Benioff’s work and life: the equation of music with seismology; the life-long work on all kinds of vibrations; and doing science attuned to the environment. All three aspects merged technical, scientific, cultural, and personal dimensions.

On the technical side, the transducer played a central element for understanding Benioff’s synthesis of music and science. As Jonathan Sterne has pointed out, transducers are much more than just technical objects: they are also “cultural artifacts.”¹⁵³ They translate, or, as Stefan Helmreich calls it, they transubstantiate sound, waves, vibrations in “a chain of transductions,” causing “material transformations that are also changes in how a signal can be apprehended and interpreted.”¹⁵⁴ Transducers modified ways of listening and thereby reconstituted and reorganized the world. Using and developing this technology set the field of seismology on the path from an empirical observational science to a modern geoscience. It also turned Benioff into a sonic expert, who set out to explore the full range of vibrations that could be listened to with the help of ever-more sophisticated transducers. Via translation of energy, the transducers thus unified vibrations of all kinds into a single immense field, open to further exploration, in seismology, in music, and beyond.

This transformation also readjusted the border between signal and noise, music and sound. In seismology, like music, the recorded vibration or produced tone was never pure but mixed within a cacophony of other vibrations. The technology itself used in the instruments could be the source of noise, as could be outside noise of all kinds due to the impossibility of a perfectly calm and fitting environment. Working on these problems meant continuously switching among various modes of listening, such as diagnostic, exploratory, synthetic or analytic listening. Or, to phrase it in seismologists’ terms, to do a “judicious selection of response characteristics [of instruments] based upon the noise and signal spectrums.”¹⁵⁵

Benioff himself played the role of a transducer, when he used his ears and his body to sense vibrations and tones, translating between inner and outer worlds. Steven Connor has suggested taking the self “as a membrane,…as a channel through which voices, noises and musics travel.”¹⁵⁶ The body operates like an instrument that can be attuned to its surroundings. In attuning himself to the world, in perceiving sounds of all kinds, whether human, natural, instrumental, or artificial, Benioff found the key to a richer understanding of his environment and the persons around him. The young Benioff wrote to his fiancée: “I could recognize your voice in a multitude…If one were to ask me what is Alice like I should be tempted to say ‘Hear her voice. You will know her nature’”—words that exemplify Benioff’s comprehension of the world: listen to nature, and you will get to know it.¹⁵⁷ Outside the audible range, Benioff’s instruments supplemented his ears; they extended the realm of what could be heard and unearthed previously unknown sounds and vibrations, in an instrumentally mediated synesthesia: Benioff listened through his seismological instruments, reading the visual traces of seismograms as musical scores of vibrations.¹⁵⁸ And he cultivated this form of synesthesia by designing electric musical instrument that channeled the attention toward listening for the pure tone, training his ear.¹⁵⁹

Given Benioff’s instrumentally mediated synesthesia, it is fitting that he looked for austere solutions in the construction of his seismological and musical instruments, aiming at something that may be called a self-effacing technology, chosen in the expectation that an instrument radically reduced to its essential parts would produce less noise and provide more immediate access, like a human ear. This aesthetic also guided Benioff’s expectation for musical performances where musicians should transcend the physical production of tones. He wrote to Alice: “Sing, sing on your violin! It is the only way in which to make its voice tolerable.” His ideal was to produce “a tone which is singing to a degree that leads the hearer to forget the physical process of its development.”¹⁶⁰ This quotation captures two key, but in the end unachievable, aims for Benioff: his striving for the unmediated detection and production of pure tones or vibrations with a technology that remained inaudible or undetectable. Austerity in construction was both a practical and an aesthetic choice to make the technology as invisible as possible. Minimalism as expressed in architecture from the 1920s and the focus on new materials as pursued by the Bauhaus movement inspired Benioff’s instruments, characterized by the clarity of shapes and form (Fig. 4).

By 1960, when the Earth’s free oscillations were detected, Benioff already belonged to an old guard, swept away by the technological change brought about by the computer, the transistor, and increasing mathematization. The 33-year-old Frank Press, a “most promising young geophysicist” who also “understood the modern world of government contracts,” had in 1957 taken over the directorship of the Seismo Lab from Gutenberg.¹⁶¹ The conditions that could unite seismology, avant-garde technology, and music in a single personal artistic project no longer existed. Benioff’s embrace of technology had been driven by the hope “to resuscitate aesthetics in its radical, original sense: the science of perception and feeling.”¹⁶² Seismology studied a world in motion, in its vibrations, and opened new ways of listening: not only could earthquakes shake bodies and rocks, “the most solid, the most palpable and stable of objects,” but they could even ring the whole earth.¹⁶³ For Benioff, the vibrations of the earth provided a constant source of inspiration and wonder: the earth transmitted all kinds of sounds—earthquakes, ocean surf, sunrise, storms, traffic, construction, nuclear explosions—and Benioff had the privilege of being one of the first actually to record and listen to them. Benioff shared with John Cage a fascination for listening to noise, but as something to detect rather than to perform.¹⁶⁴ Both aimed to explore sounds in all of their varieties. Whereas for Cage noise was the impossibility of silence and was music, for Benioff, the noise that emerged during systematic scientific search for the signal, was intriguing but in the end unsettling, “unrest” as he put it, requiring further investigation.¹⁶⁵

My thanks for conversations and exchanges go to the Benioff family. Mildred Benioff, Paul Benioff, Dagmar Friedman, Elena Slusser, Martha Benioff, Deborah Friedman, and Leora Benioff; to four former members of the Seismological laboratory at Caltech, Armando Cisternas, Cinna Lomnitz, Frank Press, and Stewart Smith; to the archivists Shelley Erwin, Peter Collopy (Caltech Archives), John Sheppard (Jean Gray Hargrove Music Library, University of California at Berkeley), and Mark Bailey (director of the Yale Collection of Historical Sound Recordings at the Irving S. Gilmore Music Library, Yale University); and to Gregory Good, director of the Center for History of Physics at the American Institute of Physics. I have profited from the many helpful suggestions of the anonymous reviewers. Finally, my gratitude goes to Abigail Lustig for support, advice, and editing. Financial support came from a grant-in-aid from the Maurice A. Biot Fund for the Caltech archives in 2005, and USIAS (University of Strasbourg Institute for Advanced Study) (2018–2021).