Two successive nights at the Vortex saw close connections between jazz and classical music. The difference was that saxophonist Dan Stern's gig deployed classical composing techniques as triggers for jazz improvisers, while Vienna's radio.string.quartet (the lower case is intentional, but it is definitely the only subdued aspect of their work) rework some famously high-energy jazz-fusion music for violins, viola and cello, but keep the impromptu variations to a minimum.

The band take the unlikely course of playing the music of guitarist John McLaughlin's pioneering early 70s electric jazz band, the thunderous Mahavishnu Orchestra. As they demonstrated on the much acclaimed 2007 recording Celebrating the Mahavishnu Orchestra, radio.string.quartet have their own way of evoking the original thrill, and by reducing the Mahavishnu's stadium-rock hyperbole, allow the eloquence of the compositions to shine through.

The audience had already been eased into receptivity for subtle nuances by the delicate piano/double bass improvising of opening duo Fred Thomas and Jiri Slavik. The group quickly established how effectively Asja Valcic's cello could provide both a drumlike drive and a thumping bassline, while violinists Bernie Mallinger and Johannes Dickbauer and viola player Cynthia Liao soared over it.

The violinists took the freest approaches, with Mallinger's urgency echoing both Mahavishnu's maverick country-fiddler Jerry Goodman, and McLaughlin's guitar. Meeting of the Spirits turned an opening dark riff into a percussive pizzicato section, a tumbling energy was unleashed by the fast Vital Transformation and the brooding and then ecstatic Dance of the Maya provided an encore to bring the house down.