The money that our society may have saved by tolerating poor classroom acoustics it loses in lost revenue over the victim's occupational lifetime or in higher costs for welfare, law enforcement or incarceration. As noted above, teachers also suffer from poor classroom acoustics. Teachers are less likely to talk with students or will talk with them for shorter periods when noise levels are high. After even a few minutes of speaking in an elevated voice to overcome noise, a teacher may have voice fatigue. When this happens day after day it may contribute to discouragement and burnout.
Many teachers have limited voice power and some are hearing handicapped.
Poor classroom acoustics magnify these otherwise slight limitations. Students will sense if the teacher does not understand them and may drop out. Since the strength of the unaided human voice is limited, ideal listening conditions are achieved by reducing the background environmental noise levels. Bare walls and hard ceilings are common features of today's cash-strapped schools. The Swedish standard specifies the amount of sound absorption needed to control reverberation for each type of space.