Call it a pre-emptive strike. A couple of weeks ago, in a sunlit Wallingford living room,composer Jeremy Turner got the information out there before one of his colleagues beat him to the punch. His shameful admission: His first paid composing gig was for a Preparation H commercial.

That confession, which got a huge laugh from a crowd of chamber-music aficionados, is precisely the kind of tidbit that delights the Seattle Chamber Music Society Commissioning Club — not just for its humor, but for the light it casts on the nitty-gritty of becoming a composer in today’s commerce-driven world. With his secret out of the way, Turner was ready to present “The Inland Seas,” a composition inspired by the Great Lakes, and discuss his unusual career.

The Commissioning Club was founded in 2007 and commissions a new chamber work for the SCMS summer festival every year. The club has 40-odd subscription holders (either couples or individuals) who pay a minimum of $300 a year for three years to participate. SCMS artistic director and world-class violinist James Ehnes decides which composers will be commissioned. The program is the brainchild of SCMS founding directorToby Saks, who died in 2013. Club chair Geoff Groshong describes the event as “very egalitarian … a supportive place for new works and for asking questions. The members get something out of it.”

The informality of the salon was evident as Turner walked attendees through his new piece, focusing equally on musical content and what goes on behind the scenes. “Seas” was written for Ehnes and mandolinist Chris Thile, both close friends of Turner’s. Thile, who won a MacArthur Fellowship — the so-called “Genius Grant” — in 2012, is the ultimate crossover artist, performing with his bands Nickel Creek and the Punch Brothers, as well as on the concert-hall circuit.

“He plays everything,” Ehnes said in a recent phone interview. “He’ll play a Bach partita and then he’ll play a Tori Amos song and then he’ll play some bluegrass. It’s just all over the map. But even when he plays with a great deal of abandon, it is always with an incredible refinement and care.” He added, laughing: “It’s amazing to me that he can have an audience of 1,500 drunken frat boys loving what he’s doing, and then he can play a Bach sonata and have 1,500 middle-aged, classical-music lovers also loving what he’s doing.”

Ehnes was skeptical about Thile’s classical-music forays at first (“Do I really need to hear somebody play Bach on the mandolin?”), but was won over by a 2013 concert at Meany Hall where Thile played excerpts from Bach’s sonatas and partitas. “I was like: ‘Wow, I really think that every violinist needs to hear this.’ ”

Once Ehnes booked Thile to play SCMS’ 2016 Summer Festival (July 5-30), he immediately wanted Turner, his old roommate at Juilliard, to compose something for the two of them. “To write a piece for two of his closest friends,” Ehnes said, “he was going to put his best effort into it.” Turner, a former assistant principal cellist with New York’s Metropolitan Opera Orchestra who has played at several SCMS festivals, is “a composer with a unique voice,” Ehnes said, “someone who I think we’re catching at an exciting time in his burgeoning career.”

What are Turner’s special gifts? He’s one of those “annoyingly talented people” (Ehnes’ words) who can pick up and learn a new instrument when the urge strikes him. “So he writes extremely well for all instruments.” Turner, 40, wrote his first song at age 2: a hilariously lugubrious two-note piano ditty, “There Was a Tow-Truck in the Desert,” which he played for salon attendees. (He said it drove his parents crazy.)

He taught himself guitar and started a band with Metropolitan Opera drummer Michael A. Werner (now familiar to Seattle Symphony audiences as the orchestra’s principal percussionist). “We would play club shows downtown in New York, sometimes after operas,” Turner said at the salon. “We would get out of our tuxedos, hop in a cab.” Five years ago, he left the Met to see if he could make a go of it as a composer and freelance performer, collaborating with Sufjan Stevens, the National and, most recently, LCD Soundsystem. “At first it was just commercials and then short films and then documentaries and then some art installations,” Turner said. “And now it’s this concert music.”

Turner told club members that his first reaction to the SCMS commission was: “Wow! Amazing! This is great.” His second reaction was panic: “How am I going to write a piece that’s going to challenge these guys? Because they can literally play anything.” He also faced the technical issues of writing for two instruments “tuned in the same way, in the same sonority.” He wound up taking a compositional cue from Thile’s maverick style: “Chris does so many interesting things … beyond just playing chords and notes. Sometimes he does this fretted percussive sound, and sometimes he plays above the nut and makes these weird ringing tones. And sometimes he knocks on it.”

“The Inland Seas” evokes the weather and waterscapes of a region Turner got to know after moving to Michigan at age 8 — he’s fished in most of the Great Lakes and swum in all five of them. During his walk-through of “Seas,” he talked about shipwrecks, storms and dwindling wolf populations. In its opening movement, the mandolin beats out a frantic SOS signal while the violin conjures the increasing tumult of a ship about to founder in the waves. The second movement, Turner pointed out, features a ghostly “wolf howl” for violin. “The Inland Seas” premieres July 11 — and it won’t be Thile’s only performance at the festival. “We’re going to do a pub show afterward,” Turner said, “which will be fun.”

Michael Upchurch: www.michaelupchurchauthor.com