It’s emblematic of Seattle Symphony conductor Ludovic Morlot’s devotion to new music that the first commission of his tenure (co-sponsored with orchestras in Manitoba and Ontario) was given to Nico Muhly—arranger for Björk and amanuensis to Philip Glass, among other resume highlights—who’s surely the highest-profile composer of his age (30) today. It speaks to Morlot’s desire to keep SSO audiences abreast of classical music’s newest and most buzzed-about names and developments. After spending years birthing two operas (the second, Two Boys, premiered in London in June and is slated for a Met production in 2013–14), Muhly had stored up ideas for this project—a sort of bucket list for a work in which he could do whatever he wanted without being tied to a libretto. The result is the 17-minute So Far So Good, which the SSO will premiere this weekend. “I knew there were a couple things I wanted to do in the piece—all my weird obsessions.” he says. “I’ve never written anything big for trumpet, so I knew there was going to be a big trumpet thing. There’s also a kind of obsessive drone section where all the pitches just kind of collapse into one note.” Muhly also relished the opportunity for “large sonorities, where everyone’s playing the same chord . . . almost like listening to a crowd of people speak, a kind of ecstatic mumbling, and that’s sort of how it ends.” (The title refers to a process of constant unfolding and transformation, a central concept of the piece.)