The location of these sources is controlled in real-time through gestures or arbitrary control messages arriving from the network . The visualization software has access to the room database and real-time parameter estimates from the spatialization software. Since it has no access to the real sound pressure levels in the room it must estimate these based on an acoustic model of the room. The image source method was used because of its amenability to real-time computation. The sound sources in this case are organ pipes.
Pressure is shown using a color map on horizontal cut planes through the space.
These movable planes are typically set to the average positions of audience's and performer's ears. Multiple simultaneous cut surfaces may be necessary, for example, for balcony seating in large theatres. It is interesting to contrast this volumetric visualization with traditional audio metering where scalar signal levels are displayed for various nodes in the signal processing chain. Such metering is useful for managing signal levels in the electrical elements of the audio system to avoid distortion and speaker overload. However it is hard even for experienced sound engineers to use scalar metering to predict actual sound pressure levels in many locations in a venue.