When Ina Pillat was told that a 1960s East German research lab for electronic sound generation was a world leader in its field, she didn't believe it. Pillat grew up in Görlitz, the easternmost town in the GDR, during the '60s and '70s and, like most people at the time, was more aware of her tough living conditions than the state's technological advancements. "It was East Berlin, and they weren't the best times for me and for most of us," she says. "But then I came back and I started to read about it, and I found out: it's true!" She had cause to question the achievements of the Labor für Akustisch-Musikalische Grenzprobleme (Laboratory of Musical-Acoustic Boundary Problems) during the research stages of Subharchord, a forthcoming documentary film she directs that tells the story of an East German electronic instrument that was almost forgotten.

The laboratory was founded in East Berlin in 1956. Gerhard Steinke, a young sound engineer who became its director, was tasked with research and development into stereo-sound and electronic sound generation. Countries all of over Europe were running similar programmes at the time, many of which were visited by Steinke in the years before East Germans were subject to travel restrictions. In 1961, a team headed by Ernst Schreiber, who was latter credited as the inventor of the Subharchord, completed work on the instrument.

As referenced by its name, the Subharchord was based on sub-harmonic sounds—put simply, sub-harmonics are derived from frequencies below the main frequency of signal, and are therefore do not occur naturally. In this respect, the Trautonium—and latterly the Mixturtrautonium—developed in Germany in the 1930s, was the blueprint for the Subharchord, as it used the same principals of sound generation. The Trautonium was operated by pressing a wire onto a metal plate to create a sound (it's responsible for the bird noises from Alfred Hitchcock's The Birds), but the Subharchord could, at least partially, be played like an organ.

"When it came to the [Subharchord] they could do three things," says Pillat. "TV shows—make sounds for TV things or films—they could make sound for radio plays or pieces, and they could experiment with new sounds." As word of the Subharchord spread, demand for it grew across these mediums. Composers were interested in the instrument's "futuristic" sound, and the lab fielded requests for its use from across Europe and as far afield as the US.

One day in 1968, after learning of the Subharchord's developments in sound generation, a group of three Norwegians who were stationed in West Berlin crossed the border to visit Steinke's lab. Aside from a note regarding their visit in his diary, the exact events of that day remain unclear. What Steinke did know, however, was that shortly after their visit, a Subharchord was secretly sent to Oslo by his superiors, despite the lack of any official trade agreements between East Germany and Western countries.

A single unit would not have been too much of a loss to the lab—if the Subharchord had reached mass production, as was intended. Steinke's team had continued their work on the instrument's development throughout the '60s, but as the decade wore on, and the cultural climate in the GDR began to shift, the team was eventually instructed to focus on other projects. In 1970, a private company attained the rights to manufacture the Subharchord on a commercial scale, only for the state to shut it down before a single instrument was produced. In total, only seven Subharchords ever existed.

Given the scarcity of the instrument and its historical and cultural capital, it's unsurprising that credit for the Subharchord's eventual re-emergence is contested. Cursory research suggests it was Berlin-based musician Manfred Miersch who rediscovered the Subharchord, but Pillat—and, according to her, those closest to the instrument and its history—contests details of this account. Subharchord.com, a site set up by Miersch sometime between 2002 and 2003, states: "In the course of extensive research on the history of electronic music instruments, in 2000 Manfred Miersch, a Berlin artist and musician, made a truly remarkable discovery: the trautonium is not the only instrument of its kind; another exists that produces subharmonic sounds — the 'subharchord.'" Miersch published a four-part series on the instrument in the German Keyboard magazine in 2003, and in 2004 released recordings of the Subharchord as a seven-inch single, Subharmonische Mixturen Mit Dem Subharchord.

For Carsten Seiffarth, founder and director of the Berlin-based sound gallery singuhr – hoergalerie, it was 2005 when he first came across the instrument. "There was an exhibition in the Academy of Arts in Berlin," he remembers, "where the title of the big exhibition was Archives because they opened their new location in the middle of the city, and they were asking five artists to work with [the academy's] archives." One of those artists was Raster-Noton co-founder Carsten Nicolai, AKA Alva Noto. "The Academy of the Arts has an electronic, or electro-acoustic, studio," Seiffarth says. "They found an instrument standing somewhere in the middle of nowhere and [Nicolai] said, 'What was that?' and it was the Subharchord."

From June 18th until August 29th, 2005, Nicolai exhibited Sub Vision at the Academy of Arts. The audio/visual piece was based on sounds of the prototype Subharchord that had been discovered in the academy's vaults and subsequently refurbished and modified to receive MIDI data.

As co-director of TESLA in Berlin, Seiffarth commissioned Werkstatt Klangapparate (Workshop Sound Apparatus) in 2007, a year-long project that invited four musicians to re-contextualize historic sound devices. Alongside works centred on a Trautonium and the Talking Machine—an acoustic speech synthesizer designed by veteran British artist Martin Riches—Raster-Noton's Frank Bretschneider and Moscow-based synth expert Benzo were to prepare performances with the Subharchord. A unit had been traced to the former GDR broadcasting house at Nalepastrasse (now known as Funkhaus Berlin) but it was in need of repairs. A 70-year-old engineer, who maintained a private studio at the site and kept a vast collection of compatible components, agreed to take on the renovation, and loaned the unit to the TESLA studio for six months. Captivated by the instrument, Bretschneider worked extensively with the Subharchord's unique narrow-band Mel-filter and Rhythmisierungseinrichtung (rhythmization installation). The Kippschwingungen performance was eventually released as an eight-track CD in 2012.

"From the first day, I knew it could be a film story," says Pillat. After studying media in Cologne, beginning work as a documentary film maker and living in Berlin for eight years, in 2009 Pillat moved to Oslo with her husband, Ivar Smedstad, who was to take up directorship of Atelier Nord, "a project base for artists." Carsten Seiffarth was a friend of her husband's, and learned that Pillat was looking for a new film project. The trio also shared a mutual friend in Per Platou, who heads up the Production Network for Electronic Arts in Oslo, and had similarly begun research into the Subharchord, and in particular its links to Norway—it was later discovered that the Subharchord smuggled from Gerhard Steinke's lab in the '60s had ended up in Trondheim as an exhibit in a museum.

Pillat won funding for her film and travelled to Berlin to meet the now 81-year-old Steinke. The film's synopsis describes him as an "energetic, curious and cheerful audio expert." Subhardchord joins Steinke as he pieces together the history of his team's instrument, but is told through the eyes of Pillat. "It will tell the story about me how I come to this instrument," she says, "and how I found out things, and how I meet people and then with interviews and personal, political stories, musical stories." In speaking with Pillat, there is a palpable sense of pride in her bringing the overlooked achievements of her compatriots in the '60s to a wider audience.

On February 2nd there will be an afternoon dedicated to the Subharchord as part of the 2013 CTM festival in Berlin. Funkhaus will open its doors for performances from Frank Bretschneider, Biosphere (who will provide the film's soundtrack) and The Pitch Ensemble, and Frederic Rzweski. Seifarth has been asked to moderate, while Steinke will give a lecture and Pillat will present material from the film. "I will have access to the actual Subharchord only four days before the performance," says Geir Jenssen, AKA Biosphere. "Because of this I've been forced to work with some old recordings of the instrument made in GDR in the '60s. I've sampled the parts that I like and made new music from it."

Museums in Berlin, Vienna, Prague and Trondheim house what appear to be the last four remaining Subharchords, but for Seifarth, his concern is more over the preservation of expertise rather than people hearing first-hand the instrument's "special" sound. "I didn't find anybody from the younger generation to take over the knowledge of these old people," he says. "There are only two people who know how the instrument works and they are 81 and 85." As for Pillat's role in all of this, she says it was her aim to reflect the human-interest element of the Subharchord story. "I wanted to make a film for everybody," she says. "I would really like to bring this story to the people. It's very dramatic and also humorous. It's a good story—that is the first thing."