Ushers were handing out earplugs in April at the Blair School of Music’s performance of Ballet méchanique. We needed them. American composer George Antheil’s 1924 masterpiece was like The Rite of Spring on steroids, a jackhammer of a piece that left no percussion sound unexplored. Eight full-size Yamaha Disklaviers played huge chords, tone clusters and glissandi while sampled alarm bells, sirens and propeller sounds screamed out of speakers. Conductor Michael Holland and 13 members of Blair’s Vortex percussion ensemble accompanied the robotic pianos, creating a complex tapestry of rhythmically asymmetrical counterpoint. The crowd roared its approval at the end, and the entire piece was repeated as an encore.