Narbeth couple Greg and Jenn Seltzer had a few rules in mind when they launched the Philly Music Fest (phillymusicfest.com) in 2017: the venues had to be independently owned, the performers had to have genuine ties to the region and a portion of the ticket sales had to benefit music programs at local schools. Seven years later, the first-of-its-kind festival is back, featuring 21 bands including names like Amos Lee and Devon Gilfillian. Talk about the sound of Philadelphia.