classes:  lecturer. need to improve the quality of equipment in the classroom because there are often cases of audio signal interference between the rooms.  curriculum. need to improve the quality of equipment in the classroom because there are often cases of audio signal interference between the rooms.  facility. need to improve the quality of equipment in the classroom because there are often cases of audio signal interference between the rooms.  general. need to improve the quality of equipment in the classroom because there are often cases of audio signal interference between the rooms.