The main concert hall at Philadelphia’s Kimmel Center is a beautiful thing to behold, but its acoustic has never quite measured up to the advance billing. Several studies have recommended significant acoustical changes, but thus far, the center appears content to stand pat. “So is this it? Is the hall’s sound fixed in its not-quite-good-enough state? Will Verizon Hall ever achieve the greatness planners promised, and, if so, does anyone have the wits, will and musical authority to get it there?”