In modern experimental music, and especially among a number of musician-composers emerging in America during the Sixties, a fixation on process and awareness became a structural hallmark, exploring the gradual change of sonic materials, built environments, and the human body. Though much maligned as a term by its practitioners, figures like Steve Reich, La Monte Young, Philip Glass, and Terry Riley were among these 'minimal' composers; askew of them were electroacoustic explorers like Alvin Lucier, Robert Ashley, and David Behrman. In recent years, composer Sarah Hennies (b. 1979) is forging new paths of reduction and expansion. Spectral Malsconcities (2018) consists of six linked and varied sections; it is constructed in a way that ensures the musicians are never completely in sync, and in fact they generate sounds that continually destabilize the standard ensemble goal of togetherness. As Hennies put it recently, 'this piece is an example of performers elevating something beyond what I thought it could be.

I wrote a piece that I thought would intentionally create mistakes. You ask somebody to repeat a very different polyrhythmic contrapuntal page of music 25 times, and it is going to fall apart at some point and then come back together. However, the musicians are so good that they played it exactly as it was written, which is better than what I thought it would have been if they were messing up...' Taking its cue from a two or three player-one vibraphone piece called Settle, which was composed by Hennies in 2012, Unsettle (2017) is a spare and summarily weighty composition that finds space monolithic and driving. The score is economic, taking all of two pages to spin out 33 minutes of music. It begins with una corda fluttering, the passing of time held in single E notes bent at the edges and limned by vibraphone haze, gradually augmented by rumbling clusters and brassy, clanging bells. The inflection and increase in density among otherwise apposite events create an extremely intense landscape of tension without release, though powerful as well -- the closing minutes of pedal movement, muted piano strings, and bell clatter (à la Iannis Xenakis' Bohor I) lead into prepared twang and supple metallic accents.

Ditto the shock of vibraphone and muted clamor at minute twenty, carrying enough distorted overtones to defuse one's skull. Sublime and utterly physical, explosive and statuesque, Spectral Malsconcities and Unsettle are complementary works that display another rich stage of Sarah Hennies' practice. Her world of creativity is welcoming, but like all art of significance, you have to do the work in order to share in the experience. At the end, and wherever that end is, the rewards will be great