J. P. Jullien
IRCAM 31, rue St.-Merri, 75004 Paris, France
The room acoustics laboratory at IRCAM has undertaken a series of objective and perceptual measurements in different concerts halls and opera houses throughout Europe. The measurements consisted in recording impulse responses at different seats, using a directive loudspeaker (at different locations on stage) oriented in various directions. The listening tests were undertaken during concerts with subjects seated at the measured locations. The subjects were asked to describe the room acoustic quality with the help of a structured questionnaire, based on the results of former psychoacoustic tests. The links between perception and the criteria based on the time distribution of sound energy, established in laboratory experiments, were confirmed and/or refined. Furthermore the results of this campaign emphasize dependencies of the perceptual factors on the spatial distribution of energy. Subjective description is strongly affected by orchestra size as well as location and directivity of the instruments. Thus a single location, directivity, and orientation of the source used for the measurements will not suffice for properly describing the perceived room acoustic quality. The analysis of the relations of subjective and objective data collected in that campaign, together with additional experiments, gives some hints as to how to define an appropriate measurement protocol.