Jason Palmer’s “Rhyme and Reason” is the first release from Giant Step Arts, a nonprofit dedicated to giving underappreciated but visionary jazz musicians the support they need to make quality live albums. Palmer is a perfect first subject for this: He’s a thrifty improviser with a vast dynamic range and an ambitious composer, but he’s hardly known. On “Herbs in a Glass,” the album’s opener, he propels his band mates (the tenor saxophonist Mark Turner, the bassist Matt Brewer and the drummer Kendrick Scott) through a squirrelly nine-beat rhythm; the odd, open-ended meter ends up pushing his intense melody into the plain air, giving it a billowy freedom. RUSSONELLO