Audio-visual interactions in loudness evaluation

In psychophysical experiments, the influence of the presentation of visual stimuli on the loudness evaluation of sounds from traffic noise has been investigated. In a first experiment it was shown that the colour of the visual stimulus can influence loudness evaluation in such a way that – for same acoustic stimulus – the loudness of a red train can be rated 15 % higher than the loudness of a green train. The following set of experiments was devided into two groups: on the one hand, visual stimuli from still pictures and on the other hand visual stimuli from moving pictures. As subgroups of the still pictures either pictures not related to the sounds or pictures fitting the sounds were presented. An example for the first subgroup would be the sound of a train passby plus a picture of a tree, and for the second subgroup the sound of a train plus the picture of a train. As concerns the moving pictures, also two subgroups of stimuli were studied: in one case, the video was taken from a fixed position, and in the other case from a moving position such as in a driving car. Moreoever, the presentation was either in a sound proof booth for psychoacoustic experiments via headphones and a head mounted display or in a simple car simulator. The magnitude of the influences of the rather different types of audio-visual interactions on loudness evaluation of sounds from traffic noise generally increases for more “realistic” situations: relatively large loudness reductions (8 %) are found, when moving pictures taken during a car ride are presented in a car simulator.