In London during the mid-60s, the seeds were sown for a second industrial revolution. Industrial music, the new genre so dubbed a decade later by Throbbing Gristle (who named their short-lived record label Industrial Records), opened its Pyrex eyes, stretched its cranelike arms, and yawned a deep, quiet, steel wool yawn in the music of the British improvising ensemble AMM. Lesser known than Gristle or later industrialists like Controlled Bleeding, Illusion of Safety, and Einsturzende Neubauten, AMM nevertheless paved their noisy path.

One of the original musical democracies, AMM embraced indeterminacy and sonic noncoherence, vigorously asserting an egalitarian relationship between players. Breaking from the jazz tradition in which key AMM members percussionist Eddie Prevost and saxophonist Lou Gare cut their teeth, AMM undermined traditional hierarchical roles, most notably the one that assumes the rhythm section is a slave to the soloist. (Interestingly, they reassume those roles in the just reissued mid-80s duets disc called To Hear and Back Again, which is, as far as I can tell, an AMM release in name only.) Unlike other free ensembles of the time, such as the similarly London-based Spontaneous Music Ensemble, whose otherworldly 1968 debut, Karyobin, has finally been reissued, AMM had little interest in explicitly dialogue-based or interactive improvising, opting instead for the gradual assembling of discrete sound elements into a giant patchwork quilt of sound. In the end their music has something in common with ambient, but it’s a sinister and often abrasive static sound design, and one that’s far more interesting than others crafted by Eno’s children.

Following composers like Anton Webern, Karlheinz Stockhausen, and Luciano Berio, AMM gives no preferential treatment to melody and standard harmony over texture and timbre. Guitarist Keith Rowe introduced the world to tabletop guitar, a step beyond lap pedal; he rests his hollow-body jazz box in front of him and approaches it as a sounding chamber on which he can resonate objects, bow and buzz strings, and create busy little sound worlds bustling with microcosmic action. Using a shortwave radio, in performance Rowe may periodically interject broadcast sound–music, talk, fuzz, signals–into the otherwise instrumental clamor. (Like John Cage, Rowe treats the radio as an instrument.) The most intense moments for the AMM music listener have little to do with being dazzled by spectacular virtuosity; it is far more fruitful to notice the points at which the discrete elements achieve the perfect proportion, are combined and transformed–as in a chemical reaction–into something alchemical. Catching AMM in stride is like watching someone spin gold from straw.

AMM’s music has continued unabated for the 30 years since they first began to hum, shimmer, groan, grind, file, and clink. In the period before the 70s they included in their ranks composer-theorist Cornelius Cardew, whose article “Towards an Ethic of Improvisation” was influential in opening debates about that form of music making in academic circles. Two records from that period are now available: AMMusic 1966 (reissued on the British ReR label, but distributed domestically by Cuneiform) and the stunning double CD The Crypt–12th June 1968 (Matchless Records). Reissues and brand-new recordings have issued forth from Prevost’s self-run Matchless label steadily over the last few years. The most recent batch includes two mid-80s helpings. Generative Themes (1982/83) is the first recording with pianist John Tilbury, who joins Prevost and Rowe to form an isosceles trio. The Inexhaustible Document (1987) adds Rohan de Saram, cellist for the Arditti String Quartet (unquestionably the best foursome performing the truly contemporary string repertoire today), to that trio.

What is most remarkable about these two discs (both of which add material to the original LPs) is the subtle but forceful way that the new members change the basic feel of the music. Tilbury has the most difficult job, accommodating a fixed-pitch instrument to AMM’s largely tone-color, texture, and energy-oriented music. On The Inexhaustible Document he approaches from the rear, quietly introducing ambivalent, moltenly slow arpeggios, not unlike Morton Feldman. Tilbury seizes the tones that the others impart in passing, catching them in a spidery web of dissonant and sometimes consonant piano harmonies. Saram, on the other hand, plays out front, contrasting lines to the sheets and layers of sound with which Prevost and Rowe blanket the proceedings.

Newfoundland, AMM’s most recent release (recorded by the original trio of Tilbury, Rowe, and Prevost in 1992) is a masterpiece of tension and release, played out on a landscape of minuscule tinks and huge scronks. The cover sports an iceberg. However on this we get more than the tip; we get all of the 77-minute performance (ah, the pleasures of digital!). Like almost all of AMM’s work, things take time. This is not music for impatience; it grows like a glacial formation, accruing shapes, accumulating textures and densities, advancing and receding, heating up and chilling out. Early on in the disc Rowe breaks out in a relatively rare noncommunal series of violent, virtuosic bursts; but these only enhance the taut power of Prevost’s rolling toms and scraping cymbals and Tilbury’s left-of-center keyboard thunder.

So, all ye lovers of extremity in sound, just remember that AMM have been doing it since days of yore, and they do it without fancy samplers, heavy electronics, or blazing chain saws. All it takes is a few instruments, a splash of amplification, and a load of musical ingenuity.