Six months ago Pamela Cowan wrote about iPods and policies. Whilst driving this afternoon I turned down the volume on my car radio (Question Time in Parliament) and I wondered how much I had reduced the volume. I could not tell as the radio simply has a scale of numbers.
Such a measurement is common. We have heard of “cranking the amp up to eleven” but what does eleven mean in terms of decibels and, in the context of this blog, the risk of noise-induced hearing loss?
This is also particularly relevant in the discussion about earphones. The safety warnings that relate to the potential long term damage are all expressed in exposures in decibels. Yet the volume controls are shown as numbers, lines or a digital bar. There is no mention of decibels.
I realise that damage can occur from exposure to certain decibel levels over time but would not it be easier for an individual to control their exposure if volume controls on MP3 players and other audio devices were also expressed in decibels?
In this way, a warning could be issued, for example
“Ensure that the volume of this device does not exceed XX decibels or permanent hear loss may occur”
The user can then look at their device and adjust the volume according to the decibel figure in the warning. We could have a safety warning be immediately connected to risk control device – the volume knob.
I would be interested in knowing whether there are any personal audio playing devices available that do express volume in decibels.
I think that such a connection would have strong secondary benefits in the understanding of industrial- and work-related noise induced hearing loss.
Johnny and Jenny on the street have no idea at all what is a loud decibel level and what isn\’t. So loud, very loud and extremely loud are good guides.
Headphone quality counts too!
I think Graham and Kevin are on the right track for the answer of why this has not yet occurred. It is my understanding that there are several variables that could impact the decibel level. For example, the size of the room or vehicle, or whether the windows are open or closed. The distance between your ears and the noise source would also have an impact. The actual volume level is only one factor in determining the decibel level that enters your ears. Therefore, placing an indicator on the actual volume may mislead the user.
Pardon my ignorance if I am wrong – but does\’t the ultimate volume also depend on sgnal strength, sound compression and all of those issues television stations for example keep telling us when they deny that the volume is \”ramped up\” for comemrcials? If so, then decibel readings on volume controls would not be very meaningful.
Now I will wait for an acoustic expert to tell me how wrong I am?
Cheers, Graham
I suppose one of the variants in this discussion is headphones versus an external speaker. The speaker allows for a distance to the listener which would vary the exposure rate, headphones is a direct exposure inside the ear which allows for a clearer relation between volume and exposure. Perhaps I should have been more specific.
Showing decibel levels would not mean much to the average person who probably not know what a decibel was. Also, some manufacturers use different ways to indicate sound levels – my amplifier in my sound system shows minus decibels, with numbers increasing as sound levels are lowered. A better system might be to indicate zones by colour, with green for \”safe\” levels, orange for higher levels, and red for unsafe levels (but why do we even allow these?).
Les, thanks for contributing. I think there is a need for consistency on whatever volume/warning controls there are so that the audio device matches the warnings or, perhaps, vice versa.
I think a dialogue on the issue is important.
Kevin