'Lectutainment', which is a coined term from 'lecture' and 'entertainment', aims at heightening students' learning motivation in a lecture. For the Lectutainment, we are making atmosphere like a theatrical performance (stage show) in the lecture by executing audiovisual effects. One of the audiovisual effects is that a synthesized whisper that only a specific student can hear is given as a verbal hint using a directional speaker(s) (parametric speaker) whose direction is adjusted to the student's position. We conducted a preliminary experiment to evaluate how students heard verbal hints from the directional speaker(s). From the results of this experiment, we think that currently it is difficult to give verbal hints only to a specific student in a lecture room.