Experimental application of active room resonance control methods in medium-sized concert halls

Room resonances can severely degrade the quality of perceived sound at low frequencies during concerts. A new method has recently been proposed to enable loudspeakers to control these resonances themselves in room without secondary control sources. These “self-controlling” loudspeakers function in a feedforward setup, using the audio signal intended for broadcast as the reference signal. Beginning with a calibration phase where impulse responses are measured between each loudspeaker and an array of microphones, control filters are subsequently calculated using field separation techniques to reduce the reflected sound field. In this work, we focus on the experimental application of this method in various medium-sized concert venues of different geometries. For each case, different microphone configurations are studied with the aim of maximizing control performance and minimizing calibration time. The active control performances obtained are analyzed in terms of RT20 reduction mapping, frequency response flattening and spectrogram homogenization.