Controlling sound in three-dimensional spaces is a complex task, challenged by the intricacies of acoustic modal structures, the variety of noise sources, and the propagation of waves. This research analyzes the influence of local impedance control on the global sound field within a parallelepipedal volume characterized by high reverberation. The employed electroacoustic transducer is based on a corona discharge mechanism and utilizes the Plasmacoustic Metalayer concept. The sound field is regulated directly by the interaction between the air particles and the ionized air produced in the discharge area. The inertia-free plasmacoustic Metalayer contributes to an increased control bandwidth. Experimental tests conducted with several actively controlled transducers distributed throughout the volume demonstrate the dampening of multiple modes. This leads to a more consistent frequency response and a broadband reduction in sound pressure levels across the entire space, demonstrated here up to 700 Hz. Numerical simulations suggest that such a systemcan also be potentially efficient in a more realistic space such as a vehicle cabin.