Nels Cline’s music brings tangibility to abstraction. Over the years, as bandleader or featured sideman, his approach has little preconception of where the music needs to go or how his audience will respond to it. It’s the next evolution in the jazz idiom. While younger generations might know Cline as the non-exemplary lead guitar of alt rock band Wilco, his career as an established jazz authority dates back to the mid 80s. Julian Lage is part of a group of gifted free musicians that are building on the newgrass fusion style created in the late 1960s. Bringing elements of chamber orchestration and jazz modalities to a contemporary string music approach is also part of the next evolution in the jazz idiom. Guitar virtuoso Lage is a member of legendary vibes man Gary Burton’s New Quartet and frequently collaborates with members of Punch Brothers, Mark O’Connor, Bela Fleck and most recently Nels Cline. The two men aren’t separated by their large generation gaps. At ages twenty-seven and fifty-nine it’s astonishing how perfectly their diverse melodic tactics blend together.

Their relatively new musical partnership kindled last year with the release of their dual-acoustic album “Room.” It’s being heiled by the jazz community as a modern masterwork of free music. Lage picks nonconcrete while maintaining some sort of a blues structure. Cline weaves in a certain sense of configuration amongst the chaos. Hardcore fans of Nels Cline Singers will appreciate the simultaneously straight-ahead yet Avant-guard configuration of the duo. I first took note of Lage’s abilities at the Rockygrass Festival in a set with Punch Brother’s Chris Eldridge. He’s somewhat of a genre chameleon though it’s obvious that the notion of any sort of style is irreverent to such a gifted musician. The Santa Rosa, California native is no stranger to the intimate venues of the bay area. Last Friday Grateful Web was invited to join in on the duo’s sold out performance at Berkeley’s Freight & Salvage Coffeehouse. The original institution for folk and free music was an impeccable setting for the special event. More packed than normal the respectful crowd of devotees sat attentively during the performance.

So quiet you could hear a pin drop is normal for Freight & Salvage. The evident reverence and sheer fascination with the music swirling around us brought a deeper meaning to the silence. It felt like we were the lucky crowd on of a live in-studio jazz recording.  Jerry Garcia once described the approach of improvisational guitar work as untying the knots. Lage and Cline took it further. They created their own musical knots then proceeded to loosen and tighten whatever felt natural in the moment. Cline’s jazz chord power-riffs were a rhythmic backbone to Lage’s powerful scale leads. At other moments Cline would unleash his lead shred majesty, rebounding alongside Lage’s inviting themes. Sipping on the venue’s strong black coffee and taking in the vibes seemed proper. The Berkeley crowd erupted into applause at the few unintentionally allotted moments.  Lage in particular seemed humbled by the crowd’s gusto, joking “we know you had other musical choices this evening.”

I was so enamored with the music-taking place that the most of the names of the many original compositions have escaped me. I do recall enjoying the provocative “Racy,” the baroque-laced “Rosemary” and most of all the extended grand finale of “Freesia/The Bond,” the later no doubt the highlight of the “Room” album. While those of you who missed the duo’s recent mini tour might feel left out, make up for it by purchasing “Room.” You can catch these two extremely busy and sought after session men in their separate respective heavy touring schedules. Alone and together, Nels and Julian move minds.