The New York Philharmonic has no guarantee that a new Avery Fisher Hall will be any acoustically better than the one it has now. Still, it’s a $300 million risk worth taking, says Anthony Tommasini, and not only for acoustical reasons. “The Philharmonic is exploring a bold plan to remove some 350 of its 2,738 seats to make room for a smaller recital hall. Quite apart from acoustics, the hall has long seemed an impersonal and inefficient public space. So these changes would be welcome, perhaps even exciting.”