The NT14 conference will be held in the Bovard Auditorium, located in the heart of the USC campus (3551 Trousdale Parkway, Los Angeles, CA 90089). It has been used to host several TED conferences and can accommodate up to 700 participants on the first floor. Balcony seating can accommodate several hundred more.
Figure: The Bovard Auditorium at USC. (flickr)