Steven Mackey’s Dreamhouse is and odd assemblage dealing with, as the title suggests, the building of a perfect home, with a libretto filled with architectural details improvised on by Mr. Mackey and tenor and fellow librettist Rinde Eckert. In addition to Mr. Eckert, who sings not only as tenor but with falsetto, and functions as speaking actor as well, the work is scored for a small Hilliard Ensemble-type vocal consort, an electric guitar quartet, and large orchestra. The music is varied in its influences, but is unambiguously American in tone and aesthetic stance.