Listening to music non-stop has never been easier since the iPod came along. But future versions of Apple's MP3 player are to be adapted to prevent users from playing tracks at full blast through their earphones for too long. Amid growing fears that listeners could cause irreversible damage to their hearing - the highest setting is as loud as a chainsaw - Apple is developing an automatic volume control. A new patent reveals that the next iPods and iPhones could automatically calculate how long a person has been listening and at what volume, before gradually reducing the sound level. The device will also calculate the amount of "quiet time" between when the iPod is turned off and when it is restarted, allowing the volume to be increased again to a safe level. The patent states: "Since the damaging effect on users' hearing is both gradual and cumulative, even those users who are concerned about hearing loss may not behave in a manner that would limit or minimise such damaging effects."
Listening to volumes below 70 decibels is considered safe. But iPods can currently reach volumes of over 100 decibels - the equivalent to standing 10ft from a pneumatic drill - and enough to cause permanent damage after just 15 minutes. Some MP3 players can even exceed 120 decibels. In April, Apple revealed it had sold more than 100million iPods worldwide and was expecting, by the end of this year, to have sold more than 4.5million iPhones. Of those 200,000 will have been bought in Britain. Its patent application, however, is the first time Apple has acknowledged concerns over the risk the iPod poses to hearing and comes after a series of damning studies highlighted the potentially damaging effects. The Royal National Institute for Deaf People (RNID) has led calls for restrained listening and claimed that more than four million young people aged between 16- and 24-years-old are at risk of hearing damage from listening to loud music.