This is the third album from UK sax/bass/drums trio Partikel, now expanded to include a string quartet led on violin by the gifted Benet McLean, better known as a very sharp post-bop pianist. Saxophonist Duncan Eagles has sought a fresh challenge, in balancing Partikel’s familiar free-jazzy energy with a compositional coherence that draws the textures of the string players and the trio into striking and often unexpectedly seductive accords. The suite Clash of the Clans certainly opens with a ghostly swirl of dissonant strings chatter, but a graceful melody and a sleek sax solo soon purr through it. The Buffalo, a gracefully lyrical weave for Eagles, over a fine strings arrangement and drummer Eric Ford on tabla, is a standout – as is McLean’s tonally audicious solo violin intro to it. The only cover is Body and Soul, with Eagles coaxing out the melody in delicate smoke-rings on the tenor, and then as urgent improv on a taut groove. A step change for Partikel, String Theory is an intriguing insight into the depths of their resources.