Mostly, the phrase ‘concept album’ conjures up thoughts of 70s prog at its most excessive and indulgent, and rightly so. But between 1974 and 1981, Kraftwerk stood largely alone as an example of how that label could also stand for albums where an overriding concept could create a tight, streamlined, coherent classic album.

Let’s recap: 1974: Autobahn (motorway travel), 1975: Radioactivity (Radio waves, radiation, nuclear power), 1977: Trans Europe Express (a train journey across Europe), 1978: The Man Machine (gathering together classic iconic images of 20th century science fiction),
1981: Computerworld (er, take a guess).

Out of all of these, I’m focusing on Radioactivity not because it was the first of these that I bought (well, first Kraftwerk album ever that I bought) and therefore know it best, but because it’s the one I still play most, treasure most, and rate most highly as a unique, ingenious, highly textured and detailed sonic experience. And as a stone Unsung classic; does it ever get a mention in all those appraisals of Kraftwerk’s influence that you read?

A lot of overviews and reviews of Kraftwerk’s legacy seem to regard Radioactivity as a bit of an oddity. It’s certainly one of the most compact, paired-down albums they produced: one of the briefest at 38 minutes, and with no side-long epics or multi-part pieces. The 6 and a half minute title track is the longest thing here. In addition to this, there’s a smattering of very short effect-based or dialogue-based tracks that can’t be described as music at all, but are crucial binders for the central concept of radiation and radio waves. It’s also the most musically stark and austere album they’d made since Kraftwerk 2, with extremely minimal melodies, but, paradoxically, no other Kraftwerk album is as rich in small sonic details and sheer brooding atmosphere.

Play it back-to-back with Autobahn from the previous year, and you’ll also notice that Radioactivity is an absolute quantam leap in sonic sophistication. Florian’s flute has finally gone, and we’re now entering the all-synth era of Kraftwerk. Gone with Autobahn are the last rough edges of krautrock-era Kraftwerk, and here begins the smart, streamlined synth band that they would remain. To my ears, Radioactivity honestly sounds like it was recorded five years after Autobahn rather than just one, such is the change in the sound. Everywhere are grand synth melodies, clipped percussion and brilliantly-realised effects. An absolute watershed album by any group’s standards.

So what’s this little rhythmic thud that opens the album? Check track titles…ah, a Geiger Counter. It gathers speed, gathers other Geiger counter noise around it, then leads into the morse-code opening of the title track (it’s the first verse in morse code! genius!), with walls of ghostly chroal synthesiser and an almost Oriental-sounding melody. “Radioactivity.…is in the air for you and me”. If there’s a more emotionless, deadpan vocal ever been recorded, I’ve yet to hear it. This is a record of atmosphere and isolation. THUD THUD hisssss goes the sombre percussion track unrelentingly as various mechanical sound effects gather around it. We’re deep into the hub of the powerplant now. Or, auf deutsch, das Kraftwerk…

After this comes the even slower, funereal thud of Radioland. This is pure isolation in sound, a solitary radio ham scanning the airwaves for signs of life. Only a robotic, mechanised voice answers him (and it wouldn’t be the last one used in this band’s subsequent career…) . It’s not a track without humour, though: did anyone recognise that little melodic snippet midway through the first verse? Yup, it’s a cheeky quote from Tanzmusik. ‘New’ synth Kraftwerk pays neat homage to ‘old’ experimental Kraftwerk. However, it could also be said that the synth melodies and chords on the Ralf & Florian album pointed the way forward to many of the tracks on this album.…

It’s not all short-wave hamming though. There’s fun to be had next as “Airwaves swing” and “distant voices sing” to a bouncy, upbeat tune that would be joyful if it didn’t still sound so weird, detached and foreboding, as if the only person listening to the radio was a nightwatchman in an empty factory at 2am. You’ve probably guessed by now that this isn’t the ideal record to play sunning yourself on the beach.

And what’s that tiny snippet of ascending melody that makes up Intermission? Hmm, sounds like a little quote from the ‘fast section’ of the Autobahn title track to me.…crafty buggers. Side 1 ends with News, which is just that, as overlaid tapes of German newsreaders report various advances in nuclear technology that will revolutionise modern life in Germany.

By 1978, it was all “We are the robots” for Kraftwerk. Side 2 of Radioactivity just starts with one robot voice reciting The Voice Of Energy. One line translates as “I am your servant and also your master… guard me well.” As a still-impressionable 14 year old when I bought this album, this track used to scare the shit out of me.

Antenna is always the highlight of this album for me. The tune, the buzzing and squelching effects, the ethereal, ultra-reverberating vocal harmonies on the German verses…utter arranging genius. Lyrically, we’re back to the lone radio ham looking for contact with the outside world. Or maybe it’s just about radio waves being transmitted. Or both. Sounds cold and isolated as a ham radio station in Antarctica anyway.

Things just get weirder from there. Radio Stars doesn’t have a tune as such, just a piercing, repeated tone and echoing, disembodied vocals about radio waves in deep space. There’s tiny hints of melody in the occasional vocodered vocal, but mostly we’re in the utter blackness of the universe here, floating, airless. Uranium, which follows, brings back the freaky robot voice whispering malevolantly about radioactive decay over a haunting chorale that transports us straight into 2001: A Space Odyysey territory, uncovering the monolith.

The last pair of tracks are instrumental, and after all this groundbreaking innovation, it’s time for Ralf and Florian to relax a bit and look back a bit. Both Transistor and Ohm Sweet Ohm could have sat comfortably on the 1973 album that the duo gave their two names to; Transistor also always reminds me of Cluster in its repetitive melody. As one Krautrock fansite I’ve read notes, who influenced who? On the final track, we get the vocodered-vocal loop that was sampled by the Chemical Brothers for Leave Home, then a stately lament that slowly gathers pace, ending the album on a gentle, understated note. Dusseldorf can go safely off to sleep, knowing that nuclear energy is keeping their homes and businesses powered, and radio waves are spreading their daily communications. But what about all that waste uranium? Will it be safely contained and buried? “I am your slave and also your master”, said the voice of energy.…