Prolog to "Fifty Years of Acoustic Feedback Control: State of the Art and Future Challenges"

Ever since the microphone was first connected to a loudspeaker, acoustical engineers have had to grapple with the unintended consequence of acoustic feedback, a phenomenon that occurs when the sound generating from a loudspeaker inadvertently returns to the microphone in a closed loop. This feedback not only deteriorates sound quality and limits achievable amplification, but its most characteristic feature is the howling effect it creates. In this paper, the authors evaluate current methods available for dealing with the problem and identify the challenges facing future research in developing reliable and affordable solutions to the problem of controlling acoustic feedback.