Much of Lucier's work since the late '60s concerned itself, to one degree or another, with the relationship of pure sine tones to those produced by human-manipulated instruments, their similarities and divergences. His pieces sometimes skate the boundaries between art and science experiment, although the best of them have elements of both and don't allow the listener to make such simple distinctions. Such is the case with the two compositions presented on this marvelous recording. "Navigations for Strings" was inspired by sounds Lucier picked up on a pair of antennae while on a mountaintop in Colorado. The ghostly atmospherics -- what Lucier terms "sferics" -- originated in the ionosphere as natural radio transmissions and were heard as swooping, whistling tones occupying only several notes on the octave but including countless gradations between. Writing for string quartet (here, the Arditti Quartet in a masterful performance) he has the players play ever so subtly shifting intervals, very gradually sliding from pitch to just adjacent pitch. Sometimes, as in much of his work, the extreme closeness of the pitches produces audible overtone beats. The general effect, however, is one of existing in a gloriously rich sonic world, with arcing drones constantly in flux overhead.
More elaborate and ultimately more wonderful, "Small Waves" finds the composer positioning six vessels of water at various places in the room with microphones inserted into the vessels' necks. This causes varying levels of feedback to occur, the amplitude and pitch affected by the room they happen to be in. The performers (here, once again the Arditti Quartet augmented by Hildegard Kleeb on piano and trombonist Roland Dahinden) are instructed to attune the pitches they produce as closely as possible to a given strain of feedback. Additionally, the water level in the vessels is changed periodically during the performance, thus altering the character of the feedback. All technical details aside, the resulting swirling mass of sound is utterly immersive, endlessly fascinating, and quite unusually beautiful. Once again, subtly throbbing beat patterns emerge but here the texture is so rich one often isn't exactly sure about the source of this or that sound. This may be Lucier's most perfectly realized work since his masterpiece, I Am Sitting in a Room. Highly recommended.