Local guitar auteur Neil Haverstock (pictured) is among the new leaders of the microtonal movement, a compositional philosophy that eschews the traditional 12-tones-per-octave scale. Rather, Haverstock and the six players who will perform as part of the sixth annual Microstock Festival, Friday November 3 at St. Pauls Methodist Church, prefer to investigate the little sonic spaces in between. Haverstock is known nationally for his experimental compositions, which utilize both 19- and 34-tone scales; the spacey, spellbinding sounds are well represented on his current, aptly titled disc, Other Worlds. Haverstock will be joined on the gorgeous St. Pauls stage by Chris Mohr, whose custom keyboard traverses no fewer than 53 tones; Yoko Hiraoka on the Japanese stringed curio, the koto; and John Starrett on percussion instruments, including the waterphone. The festival, presented by Creative Music Works, is a chance to sample an art form that is daring, instructive and, in spite of its name, by no means small.