Sistemas Inestables is a Santiago, Chile based trio in a two drummer, one bass set up that produces a combination of fusion jazz and post-rock with perhaps a touch of prog, where each member frequently pulls double duty on keyboards and electronics. They play with a level of power that gives their sound an unmistakable rock edge, which may have gotten more pronounced since Santiago Corvalán took over the bass following their 2018 debut album, O. By giving themselves longer running times on their pieces, the band takes the opportunity to explore and expand on their thematic elements, and use that space to shift dynamics for a more dramatic effect. Their work has been exclusively instrumental thus far, and for some folks, it may take a bit more than a casual background listen to reveal its rewards.