Free-jazz noise is only one weapon in the larger arsenal of Flat Earth Society's sound, but it's applied to its fullest in tracks like "Zonk," a five-minute horn-and-percussion workout that'll leave you ... well, zonked by the end of it. There are also beautiful choral arias like "Ich Kann Ohne Euch Nicht Sein," and Henry Mancini-worthy car chases like "O.P.E.N.E.R." There isn't a jazz subgenre that FES doesn't flirt with, including Looney Tunes-type cartoon spasms and swooning Glenn Miller romanticism.
Part of this diversity derives from the fact that ISMS is a compilation of previously recorded work and new material. Fortunately, there's no inconsistency in terms of recording quality or performances. FES nails every distinct style, most of it original in composition, save for an obscure gem like Louis Armstrong's "(Little) King Ink." Bandleader and clarinet-player Peter Vermeersch seems to have absorbed every kind of recorded jazz from 1930 onward and applied it to a writing approach that fuses high classicism with raunchy postmodernism.