SYDNEY, NSW - AUGUST 17:  A man listens to an iPod MP3 player through earphones August 17, 2005 in Sydney, Australia. Research conducted by the National Acoustic Laboratories, to be released by the Australian Federal Government today, has found that up to a 25% of people who use iPods or other portable music devices will suffer from hearing problems as a result of listening to their players at 'excessive and damaging' levels.   (Photo Illustration by Ian Waldie/Getty Images)