With sadness I note the passing of Maryanne Amacher, a sound artist whose work impressed me the first time I heard it many years ago. She will no doubt be best remembered for her massive multi-room installations, which she populated with "sound characters" whose interaction she considered in narrative terms. Sadly, I never had a chance to hear any of these, but her recorded work is very powerful on its own terms. The installations defied documentation on record for decades, but some of her work started appearing on compilations in the mid-1990s, notably the Asphodel Sombient Trilogy. Eventually John Zorn persuaded her to release a solo CD on Tzadik, Sound Characters (making the third ear), in 1999, followed by a second one almost ten years later, Sound Characters 2 (making sonic spaces).
The aspect of her work that initially attracted me was a phenomenon known as otoacoustic emissions, where the inner ears generate additional tones to what comes out of the speakers. Even on a home stereo (heck, even on a car stereo, the only listening location at the time with sufficient privacy), my ears bristled and quivered, unlike anything I had experienced before or since. Several passages on her Sound Characters exhibit this phenomenon, which of course relies on sound circulating in a space and is thus completely absent on headphone listening. Sound Characters is a sort of compilation album, containing material from a couple of different installations as well as some piece apparently composed just for the CD. Sound Characters 2, on the other hand, is a documentation of one installation, at the outdoor plaza of the Palacio de las Bellas Artes Museum in Mexico City, presented as a complete narrative. While the liner notes for the first CD follow the typical Tzadik six-panel standard, there is a sixteen-page booklet with the second, complete with photos and diagrams and several essays about the installation (although you might need a magnifying glass to see much in the diagrams). Both CDs are still in print, and it's been a pleasure to hear them again.
Her wikipedia page has already been updated several times since her death yesterday, and someone has already started an online archive to document her work. The only real obituary I've seen so far is from the Chicago Reader, and Kyle Gann also has a nice remembrance of this singular and amazing artist.