Audiometric examination was performed on 120 subjects who engaged in speaker research or in administrative works in speaker production, 10 subjects who used in their work insert-type receivers, and 30 recording engineers.
The results were analized in reference to the number of years in works.
Present study revealed that:
1) there was no tendency that hearing was impaired in speaker engineers or in other people exposed to sound from speakers.
2) the mechanism of hearing loss at 4000Hz found in recording engineers was appeared either different from the ones seen among sheet-metal workers or in speaker engineers.
3) the reproduced sound through speakers seemed not to cause hearing loss in human.
4) the direct sound produced by instruments may cause hearing loss as in the case with noise, however, further observation is to be done to prove definite effect of the sound from the instruments.
