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Re: Helping Apple get iPod hearing protection right
Information on damaging listening levels with iPods can be found in the following published article. Obviously, there's more to be evaluated, but there are obvious reasons why Apple's solution is inadequate for really helping their customers to protect their hearing:
> ----- Original Message -----
> From: "Eric LePage" <ericlepage@xxxxxxxxxxxxxxx>
> To: AUDITORY@xxxxxxxxxxxxxxx
> Subject: Helping Apple get iPod hearing protection right
> Date: Fri, 31 Mar 2006 15:08:01 +1100
> Hi John Lazzaro,
> Thanks for the news item. I guess putting a volume limiter in the iPod is a
> start, but they tried that with Walkmans in times past. But it's a bit like
> advertising low-strength heroin, quiet vacuum cleaners, or a Ferrari with a
> speed governor. It's the power buzz which sells things - at least to the
> group least likely to listen to warnings.
> At least if Apple has raised awareness of the risks to hearing it's a good
> SONY also issued a throw-away (red) slip with their products.
> I've added to my webpage (below) a section on our research on the effects
> of Walkmans on hearing... or more specifically the effect upon click-evoked
> otoacoustic emissions. It was originally published (1998) in the Medical
> Journal of Australia (alas not very mainstream or accessible) but is now
> available in pdf format or by going directly to the eMJA site.
> The article shows two things.
> 1) Walkmans (particularly with button earphones), with only up to 6 hours
> use per week, can be as damaging to hearing as working in noisy industry;
> over 6 hrs per week produces are larger effect, while both kinds of
> exposure can be at least twice as damaging), and
> 2) Click-evoked otoacoustic emissions are good at revealing hidden
> accumulated damage, since none of the 900+ users tested had a
> hearing loss.
> OAEs are mostly used as a quick predictor of hearing thresholds, but
> in our hands they can do much better than that; our measure of
> emission strength declines by 80 percent of its range before hearing
> levels START to shift. i.e. a "1 percent hearing loss" constitutes a
> large amount of outer hair cell damage.
> This work was quite controversial at the time, but several groups have
> duplicated the idea of using OAEs for early warning of hearing loss. Our
> methodology now gets a mention as an appendix in the new Australian/NZ
> Noise Standard (AS/NZS 1269.4:2005 Occupational noise management
> - Auditory assessment)
> Eric LePage
work address: brent_edwards@xxxxxxxxxxx