Wireless microphones are becoming popular additions to classrooms across the country, as teachers struggle to be heard effectively in classes with large numbers of students. School districts in Florida, Michigan, Minnesota, New York, Ohio, Oregon, South Carolina, and Washington are experimenting with various types of microphones.

Ironically, electronic equipment in school rooms is sometimes one of the factors that is raising the noise level and thus creating the need for amplified voice. Other factors include ventilation systems, street traffic, overcrowded schools, and hearing impairments because of middle ear infections in younger students.

Early comments from educators indicate that the reduced strain on their voices makes them more effective and patient over the course of the school day. Hearing the teacher more easily also encourages students to listen more attentively and participate in classroom discussion, educators say. This is backed up by an Education Department study in 1977-1979 that found students in younger grades showed increased vocabularies, as well as better understanding of math concepts and ability to perform math computation, when teachers’ voices were amplified.

The microphone systems range in price from $700 to $1,400, depending on style and accessories. Newer systems, which use infrared lights or sensors rather than FM radio technology to transmit sound, can run up to $1,600.