Soundfield FM Amplification: Advantages and Potential Limitations It has been convincingly demonstrated that inappropriate classroom acoustics can compromise academic achievement (see Crandell & Smaldino, 1992; 1994a, b  for reviews). One approach in overcoming the adverse effects of classroom noise and/or reverberation is the use of a soundfield Frequency Modulation (FM) amplification system. A soundfield FM system ... Article
Article  |   August 01, 1997
Soundfield FM Amplification: Advantages and Potential Limitations
Author Affiliations & Notes
  • Carl C. Crandell
    Department of Communication Processes and Disorders/Institute for the Advanced Study of Communication Processes, University of Florida, Gainesville
  • Joseph J. Smaldino
    Department of Communicative Disorders, University of Northern Iowa, Cedar Falls
  • Address all correspondence to: Carl C Crandell PhD; 461 Dauer Hall, University of Florida, Gainesville, FL 32611. Office: (352) 392–2041/(352) 392–2046; fax: (352) 846–0243; email: crandell@cpd.ufl.edu
Article Information
Articles
Article   |   August 01, 1997
Soundfield FM Amplification: Advantages and Potential Limitations
SIG 9 Perspectives on Hearing and Hearing Disorders in Childhood, August 1997, Vol. 7, 3-9. doi:10.1044/hhdc7.2.3-a
SIG 9 Perspectives on Hearing and Hearing Disorders in Childhood, August 1997, Vol. 7, 3-9. doi:10.1044/hhdc7.2.3-a
It has been convincingly demonstrated that inappropriate classroom acoustics can compromise academic achievement (see Crandell & Smaldino, 1992; 1994a, b  for reviews). One approach in overcoming the adverse effects of classroom noise and/or reverberation is the use of a soundfield Frequency Modulation (FM) amplification system. A soundfield FM system is similar to a public address system, in which speech is picked up via an FM wireless microphone located near the teacher’s mouth (where the deleterious effects of reverberation and noise are minimal), converted to an electrical waveform, and transmitted via an FM carrier frequency to an FM receiver. The electrical signal is then amplified, converted back to an acoustical waveform, and delivered to the children in the classroom via one or more strategically placed loudspeakers. The overall objectives for a soundfield FM system in a classroom are to (1) amplify the teacher’s voice by approximately 10 dB, thus improving the signal-to-noise ratio (SNR) of the listening environment; and (2) provide amplification uniformly throughout the classroom. The purpose of the present discussion is to provide an overview of the advantages and potential limitations of using soundfield FM instrumentation in the educational setting. The reader is directed to Berg (1993), Crandell & Smaldino (1992, 1994a, b, 1996), Crandell, Smaldino, and Flexer (1995), and Flexer (1992)  for extensive discussions of soundfield FM amplification technology.
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