Two classrooms of a building located in the university of Trásos-
Montes e Alto Douro campus, in Vila Real city, Portugal, were
adopted as emitting and receiving rooms. Both rooms are geometrically
similar and have the layout shown in Fig. 2. One room is
superjacent (i.e. the emitting room which is located on the second
floor) to the other (i.e. the receiving room which is located on the
first floor). There is a road next to the building and, therefore, the
sound resulting from the traffic had to be taken into account in this
evaluation. The tests were performed in July 2011, when the
semester had already ended and there were no classes.