For those involved in audio production of any kind, the auditory system is the single most important part of the whole body. We've all been guilty, from time to time, of neglecting to protect this vital set of organs. Whether it's at gigs and concerts, sports events, or listening to music a little too loudly in the car (ahem), we are all guilty of exposing our ears to potentially damaging levels.
But what about in the workplace? I asked our resident expert, Dr. Paul Power (Technical Support), about some of the hidden dangers of wearing a set of headphones (for listening or communication purposes) for hours every day, and he explains the subject of sound 'habituation'.
Dr. Paul Power (Technical Support)
Headphones are a convenient way to monitor audio, and are widely used in pro audio and broadcast. As headphones are worn for a long period of time, a phenomenon called 'habituation' occurs. Over time, the listening level will appear to decrease as the listener becomes more and more desensitised to the sound. This can cause the user to gradually increase the volume level so that it appears as loud as it was before.
Over the days, weeks, months, and years, hearing damage will start to occur. However, this is an insidious process, and its often much later that the listener realises that their hearing is impaired; by then, it will be too late!
Hearing damage happens as a combination of two factors: time and level. Therefore, keeping an eye on how long we listen for, and at what level, is essential to preserving our hearing, because once it is damaged, there is no going back.
Safe Listening Levels
It is generally agreed that sounds below 80dBA are unlikely to cause any hearing loss, even if we are exposed to them for a long period of time. However, sounds at 80dBA and above can, slowly but surely, start to irreparably damage our hearing, especially with long exposure times.
In order to prevent users from succumbing to the habituation process that Paul described, we've offered various level-limited headphones for a long time now. This unique, after-market modification can be performed on almost any wired headset and is a fool-proof method of protecting people from noise related hearing loss caused by headphone use.
Did you know that, under the Control of Noise at Work Regulations (2005), employers in the UK have a legal obligation to protect the hearing of all employees?Many other countries have similar regulations, so it is important to check with your government's Health and Safety department to understand what you need to do in order to protect your workforce, and if our level-limited headphones can assist.
So How Do We Do It?
John Driver (Head of fibre and Design)
The limiting circuit that we use is deceptively simple, but has one really interesting feature: if the user attempts to turn up the headphones louder than the limiter is set, these peaks are clipped and then fed back into the headphones at a safe level. The higher the user turns up the volume, the more and more clipped and distorted the audio becomes until barely anything is intelligible at all. This results in an incredibly annoying and uncomfortable listening experience, but is perfectly safe as the audio remains below the limited level at all times. The annoyance caused usually results in users turning the volume back down pretty quickly.