Kindle Hill Performance Space, October 17

★★★½

It is 19 years since FourPlay first replaced sheet music with effects pedals and turned a string quartet into a rock band. Back then a vague aura of a novelty act clung to them as they shredded covers of heavy metal songs and the like: a concept with a limited shelf life. They solved this by writing their own material, inevitably of varying quality. Like their new album This Machine, this concert was an all-original affair until they unleashed Rage Against The Machine's primal Killing In The Name as an encore.

These days the compositions of Lara Goodridge (violin), Shenzo Gregorio (viola), Peter Hollo (cello) and Tim Hollo (viola) touch upon such fertile patches of music where the fiddle has starred as Gypsy, bluegrass and jazz. As they range across idioms they deploy four particular attributes. One is the inherently darker sound of a quartet with two violas rather than two violins. The second is their capacity to generate grooves with real momentum, in which the cello plays a major role. The third is maintaining a string quartet's sophisticated sense of dynamics, despite the music passing through a jumble of pedals and a PA system.

The crucial fourth one is Gregorio's improvising. Whether sizzling over the fast swing of Downtown Nudnik (with its appealing tango-esque beginning), plucking a gut-bucket pizzicato solo over the slow grind of Mississippi Sinkhole, or creating an even more blistering pizzicato feature on A Grain of Truth, Gregorio was the ingredient that layered excitement atop the cleverness.

Goodridge also sang three songs, with the catchy, agitated pop of This Machine standing out. Butter Girl and Mississippi Sinkhole cried out for a bigger, belting style of voice.

Have Your Cake, Theme and Moon Over Moldau were among the most interesting compositions, with finely detailed arrangements. Such pieces open options for them in ways that the more prosaic, repetitive rock of You've Changed Your Tune and Space Party Awsomeness do not – Gregorio's searing delivery of Killing In The Name apart.

FourPlay play the Basement Saturday night.