Consisting of three fully microtonal tubas, Microtub explores group tuba music from the perspective of microtonality. Color-coded sculptural scores are used to define areas of harmonic space in just intonation, presenting geometric structures to be explored by the players over time. The 3-dimensional graphic scores used on the album Star System are subsets of the Hayward Tuning Vine, which arose out of a desire to visualize the harmonic space implicit within the microtonal tuba. Each of the balls represent pitches, and the struts between them musical intervals. In "Star System" (side A), the musicians orbit once around the star-like structure, revealing the harmonic space implicit within it. In "Square Dance" (side B), the various squares and rectangles within the score are gradually explored by the musicians, analogous to a slow dance through harmonic space. Star System was recorded at Sjobygda Art House in Selbu, Norway in April 2013. Mixed by Espen Reinertsen and mastered by Helge Sten. Microtub: Robin Hayward (microtonal F-tuba); Kristoffer Lo (microtonal C-tuba); Martin Taxt (microtonal C-tuba).