According to the invention, a speaker (Fig. 1 / 1) is mounted on a motorized carriage (Fig. 1 / 4) (Fig. 1 / 3) that moves longitudinally along a rail (Fig. 1 / 6). The entire setup is concealed behind an opaque fabric that allows sound to pass through while preventing the speaker from being seen. The device enables sound to be emitted from the speaker while controlling the movement of the carriage along the rail, ensuring the speaker remains hidden from view. The device is equipped with an indicator light (Fig. 1 / 2), attached to the carriage, which shows the speaker's position when illuminated, allowing for a comparison between the speaker's position and the subject's estimated direction of the sound when the light was off.

This device is particularly used in the field of hearing aid fitting and balancing.