Few psychoacoustic studies have been made on the influence of stereoscopy on the sound mixing of movies. Yet very different opinions can be found among scientific, esthetical or technical communities. Some argue that sound needs to be mixed differently for stereoscopic movies, whereas others pretend that image has actually caught up with sound, that was already "three-dimensional" and should not therefore be affected by stereoscopy. In the present experiment, expert subjects were asked to achieve surround sound ambiance mixings for eleven short sequences presented in both stereoscopic and nonstereoscopic versions. The results suggest that the influence of stereoscopy on the front/rear balance strongly depends on the content of the sequence and only appears in a few specific situations.