An Australian rock band, AC/DC, has postponed the US tour after the singer Brian Johnson was warned by doctors that he was at risk of "total hearing loss. This is unsurprising, perhaps, given the decades when this Australian band has been pumping out the hard rock decibel (分贝) But deafness is a concern not only for rock musicians, but for classical violinists and pop singers. In recent years has become clear that anyone around loud music a lot has reason to be equally worried.
The largest study into noise induced hearing loss in musicians was published in 2014.
Three million Germans were examined, including 2,227 professional musicians. Scientists found that the musicians were about four times as likely to suffer the noise induced hearing loss compared to the general population. Many studies into classical musicians have also found evidence of such problems. One study from the 1990s found that violinists and violists have more hearing loss in their left ear compared to their right ear. This loss of hearing is caused by the musician's own instrument, as the violin is placed under the chin with the left ear almost touching the instrument. Five studies have found that between 37% and 58% of classical musicians experience hearing loss. For rock and pop the numbers are similar, with studies finding that under half of musicians suffering from hearing loss.
In the UK, the Control of Noise at Work Regulations sets limits for exposure to noise. The lowest action level is 80 decibels on average over a working day; it is about as loud as a heavily trafficked street. When this action level is exceeded, employers must provide information and training and should make hearing protection available. When the upper action level of 85 decibels on average is exceeded, then employers must take action to reduce the noise and hearing protection becomes compulsory. What counts most in assessing the risk to hearing is the average exposure.
Exposure to high noise levels often causes temporary deafness—something that many people have experienced after going to a nightclub. While hearing usually recovers after a few hours or days, repeated loud exposure leads to permanent hearing damage. Initially, this damage is slight and unlikely to be noticed by the listener. Problems only become significant in middle age when the noise-induced hearing loss combines with the natural loss of hearing due to ageing. Often, one of the first signs is when someone finds it hard to pick out a conversation in a noisy pub or restaurant. Unfortunately, once that's noticed, it's too late.
One immediate threat is the loud instruments close by. Moving further away quietens the sound, but if that isn't possible, then other approaches are available. Often orchestras (管弦乐队) use screens to block sound from the loudest instruments. Alternatively, there are "musicians' earplugs". These decrease sound without completely blocking everything out and are very useful in a rehearsal (排练), but get in the way of balancing the sound in a concert. Professional orchestras also focus on how they schedule music, ensuring that musicians are exposed to a mixture of quiet and loud pieces. Given how loud their instruments are, drummers are particularly at risk, but using quieter practice pads and earplugs when they are not performing can lessen potential hearing loss to some extent. For rock and pop musicians, using in-ear monitors rather than loudspeakers also has the potential to reduce noise exposure, because the sound within the ear can be better controlled.
Improved technology means that the number of musicians such as Johnson having to give up performing could decrease. But student musicians need to be educated about the dangers of noise-induced hearing loss. The increasing use of headphones will also work against this — for musicians and everyone else. Unless people are careful with the volume level of their portable music players, hearing loss caused by music will increase.
