SARANAC LAKE — Most music festivals take a top-down approach: Organizers hire musicians from outside the concert location, invest in what the gig will need — stage, sound gear, etc. — and hope the bands draw enough paying customers that they at least make back that overhead cost. Like all trickle-down processes, it’s a gamble: If you build it, you hope they will come. Hobofest, on the other hand, is consciously taking things from the bottom up. Like at last year’s debut, organizers Peter Seward of Lake Placid and Todd Smith of Saranac Lake are presenting mostly local talent. Only three of the 15 acts on the bill are visitors, and two of those have ties to the area: Frankenpine has two former Saranac Lakers in its ranks, and Mother Banjo (a woman, not a band) has family living around these parts. Of the full-on local acts, some play out regularly, like Big Slyde, Steve Langdon, Roy Hurd and Jamie Savage. Others are veterans of the area’s burgeoning jam and open-mic scene.