The variable acoustics performance hall of IRCAM was designed and built for providing the largest variability possible with regard to form, volume, and surface material structure. Extending the remarkable flexibility of this room a surrounding 350-loudspeaker array has been recently installed. This system aims at the physically correct synthesis of acoustical wave fields applying wave field synthesis (WFS) and higher-order Ambisonics (HOA). This article reviews the theory of HOA with regard to the design of a feasible grid of loudspeakers for this room, followed by a discussion of methods to overcome the practical limitations of using non-uniform loudspeaker arrays.