TABLE OF CONTENTS Thomas H ttl
There are some aspects of acoustics that significantly affect the quality of our daily lives. By speaking, we transfer information and knowledge from one person to another. The sound of rain, of wind or anything else gives us orientation and aids optical perceptions. Music can fascinate us and stimulate our emotions and moods. Pleasant sounds and music positively affect health by their calming character.
The negative side of acoustics is noise. Noise is the most commonly cited form of environmental pollution. Noise is easily detected by the human hearing system. Its effects can be cumulative, and it influences our work environment as well as our leisure. Even the quality of our sleep is reduced if we are exposed to noise. In recent decades, the effects of noise on people have been studied intensively.
There is no doubt that noise has an impact on health. Very loud sounds are clearly highly injurious to people as well as animals. Table 1.1 shows sound-pressure levels (dB(A)) for common sounds. At sound-pressure levels of 160 165 dB(20 kHz) flies die when exposed only for a short time. With these exposures levels, human beings become tired, may experience facial pain, and may develop burned skin. When the sound pressure is lowered, reactions to the sound decrease. Long-term exposure to high noise levels of about 90 dB(A) can result in permanent hearing loss. Even for a steady daily noise level of 75 dB(A) for 8...
