Following previous volumes which concentrated on the United Kingdom and Europe, Cherry Red's Close to the Noise Floor compilation series set its sights on the North American experimental electronic underground of the 1970s and '80s with the 2019 four-CD set Third Noise Principle. While the scope of this set is just as wide as the preceding ones, there seems to be less synth pop here -- no early tracks from chart-toppers like the Human League or OMD -- and a greater amount of industrial and noise, particularly from acts whose work largely saw the light of day through self-distributed cassettes, or labels like Ladd-Frith and Sound of Pig. Beyond that, there's room for minimalist composers Terry Riley and Philip Glass, improv ensemble Smegma, computer music pioneer Laurie Spiegel, and avant-garde legends such as Tuxedomoon and the Residents (whose fittingly eerie instrumental "99 Space Music" sees its first release here). A few other big names crop up, such as Suicide, Chrome, and Ministry (in their early, pseudo-new romantic incarnation), but part of the fun with collections like these is uncovering total obscurities, as well as lesser-known but highly prolific entities. Blackhouse's "Be Good" is an astounding track that applies innovative distortion techniques to hypnotic drum machines and shouted vocals, all while delivering a simple, positive message. Kevin Lazar's "First Mutation" (another previously unavailable goodie) is a fun, thrilling mess of racing drum machines and several barely controlled layers of frazzled synths. While much of the third disc is given over to noise experiments, tracks on the fourth disc by Lou Champagne System, Sequencer People, Rational Youth, and Isosceles are drum machine-heavy, proto-techno exercises.