“It’s not about cars, it’s about the Autobahn,” Hütter confirms. “People forget that, but it’s very important.  It’s a road where we were travelling all the time: hundreds of thousands of kilometres from university to art galleries, from club to home. We didn’t even have money to stay in hotels so at night we’d be travelling home after playing somewhere.”

Since their pre-Kraftwerk incarnation as Organisation in 1968, band co-founders Hütter and Schneider had been restlessly searching for their signature sound in Germany’s experimental art-rock underground, recording four freeform albums and working with multiple guest musicians. In 1971, Hütter bought his first primitive drum machine. “We were mostly like the art scene band, always on the same bill as Can,” Hütter recalls. “We had jazz drummers, rock drummers, and I had my little drum machine. At one point, in one arts centre, nearly 10 years before The Robots, I had this drum machine working, playing with feedback and strobe lights. We left the stage and people were dancing to the machines. We didn’t have Kraftwerk, we didn’t have robots, we didn’t have the Man- Machine album, nothing. But the concepts were there.”

For most of 1971, while Hütter temporarily left to complete his architecture degree, Kraftwerk became a trio featuring Schneider, guitarist Michael Rother and drummer Klaus Dinger. Rother, who would later form Neu! with Dinger, remembers that even this early lineup had a rudimentary electronic agenda. “We had very simple gear,” Rother says. “Florian came from the flute, we were at the same school and he was in the classical orchestra, but at that time he was already manipulating sound with gadgets like equalizer, delay and fuzzbox. The results sounded electronic, but it was not anything near computers or synthesisers.”

The combustible chemistry between Rother, Dinger and Schneider did not even last until the end of 1971. But the guitarist is thankful to Kraftwerk for introducing him to Konrad “Conny” Plank, the producer and electronic music evangelist who would play a crucial role in the success of Krautrock and synthpop. “We tried to record the second Kraftwerk album with Conny Plank, but there was so much fighting going on,” Rother recalls. “Florian had all these tensions, he was quite the opposite of a relaxed person. And Klaus Dinger was also strong-headed; you see it in the way he played drums. He was the most forceful drummer. I looked up during one concert and saw blood flying across the stage. He’d cut his hand but he never stopped playing.”

Rother and Dinger had already left to form Neu! when Hütter rejoined Schneider in 1972. Back to their core duo, Kraftwerk began their evolution from hairy cosmic rockers to refined, streamlined, electronic chamber orchestra.

Ralf Hütter already owned a Farfisa keyboard and basic drum machine, but the tipping point came when he bought a Minimoog, then a rare luxury which famously cost him the same as his Volkswagen Beetle. Released in 1973, Kraftwerk’s third album, Ralf And Florian, saw only lukewarm sales, but it laid the groundwork for Autobahn with its programmed beats and polished synthetic melodies. Rother calls this style “Wohnzimmer”– living-room music. “We listened to quite a lot of electronic stuff,” Hütter recalls. “We were brought up within the kind of classical Beethoven school of music, but we were aware of a contemporary music scene and, of course, a pop and rock scene. But where was our music? Finding our voice, that was the use of the tape recorder. It made us use synthetic voices, artificial personalities, all those robotic ideas.”

In 1974, Hütter and Schneider recruited two new members from the Düsseldorf art-rock scene: Klaus Röder on violin and guitar, and Rother’s former band mate Wolfgang Flür on drums. The incompatible Röder left after a few months but Flür was a harmonious fit, his light-touch style complementing the increasingly minimalist, mechanised palette. Soon Hütter was proudly telling reporters, “Our drummers don’t sweat.”

Flür moved into the apartment on Berger Allee in Düsseldorf owned by Hütter’s artist friend Emil Schult, who had briefly played guitar with Kraftwerk before becoming the band’s longtime visual advisor and sleeve designer. Flür recalls long discussions about the shape and direction of the band, with “technique and romance” as their new motto.