Iara Lee's thorough electronic-music documentary Modulations may have overwhelmed as many viewers as it entranced. After all, the notion of electronica (techno, concrete, ambient, whatever) was presented in the popular press as a relatively new thing, so what were people supposed to think when they learned it was a revolution decades in the making? Modulations spouted so much music and information so quickly that the subsequent soundtrack was a necessary tool for some to sort it all out. Even then, the disc focused mainly on contemporary music. Early Modulations, on the other hand, dives deep into the roots of electronic music, covering some of the composers and experimenters that made the synthesizer what it is today. Several of these figures might be known in name only, so Early Modulations works well for those playing catch-up: It's like Cliffs Notes for cut-up technicians. The disc collects some seminal works of the '50s and '60s by such pioneers as Pierre Schaeffer, Iannis Xenakis, John Cage, Luc Ferrari, and Morton Subotnick, whose pivotal "Silver Apples Of The Moon" is often considered the first electronic composition released commercially. The humming sine waves, discordant drones, musique concrete, and robotic voice intonations may sound primitive today, but it's fascinating to consider that these compositions were created when the equipment used often didn't even have a name. Many of the pieces are abbreviated, and some key composers—notably the ever-namedropped Karlheinz Stockhausen—are oddly absent, but for the curious and budget-conscious, a handy compilation like this one can be indispensable.