[harveyadam]

I realise safety comes with responsible use but does anybody know if played at reasonable volumes they are truly safe? I ask because after discussing with a friend at work, he says that anything that "seals" the ear canal can't possibly be considered safe.

[StevieDvd]

I'll give you the standard reply I give others and apologise in advance if its too patronising.

If you use external headphones or poor fitting ipod earbuds then you tend to turn the volume up to drown out external noises. This means the total noise level going in is quite high.

If you have correctly fitted in ear pieces which seal out external noise you have a lower volume delivered to your ear drum as you are not competing with the external noise or trying to drown it out.

Imagine being in a car driven at speed and turning the volume up so you can hear music and speech properly. Leaving the volume the same put the car in a quiet spot and turn the radio on - it will be too loud.

So the point about ipod users having volumes too high is quite true but not taken a great deal of notice of. The only danger with iems is that you accidentally turn the volume up too high and believe me you notice that!

The actual seal even on a custom iem is not perfect, I don't think anyone would end up with an airtight seal. As long as you keep the tipes hygenic I don't see there would be a problem.

Steve

[NicolasB]

Originally Posted by StevieDvd

If you use external headphones or poor fitting ipod earbuds then you tend to turn the volume up to drown out external noises. This means the total noise level going in is quite high.

If you have correctly fitted in ear pieces which seal out external noise you have a lower volume delivered to your ear drum as you are not competing with the external noise or trying to drown it out.

The downside of that is that, without any kind of reference sounds coming in from outside, it is comparatively hard to judge just how loud the headphone sound actually is. It's treacherously easy to turn it up a little too high, which starts to desensitise your hearing, so that, without particularly thinking about it, you turn it up higher still, which knocks your hearing down even further, and so on.

But yes, if you're sensible then it won't cause damage. Just err on the safe side.

[spl23]

I've been using ear canal headphones for several years now - bought my first pair back in 2000, and have used nothing but ear canal phones since. I can still clearly hear the 15.625 kHz scan tone produced by a CRT TV from 10 feet away - and I'm 37. I think it is fair to say that, in my case, they have caused no hearing damage at all.

You can produce a far higher volume with ear canal 'phones than you can with conventional earbuds, so they do potentially give you the ability to really damage your hearing. However, as the previous poster pointed out, they also shut out outside noise and mean you can actually hear properly at much lower volumes. As long as you use them sensibly, they won't cause damage, and I'd argue that I listen at much lower volumes with IEMs than I used to with conventional earbuds, especially in noisy environments such as planes and trains.

As for the 'phone making an airtight seal with your ear canal - yes, it does, but the drivers in IEMs tend to be pretty small and have fairly short travel. They won't displace your eardrums any more than any other source of sound of equivalent volume.

[harveyadam]

If it is true that they do form an "air-tight seal" then surely no matter what level the volume is the pressure between the headphone and the ear membrane has nowhere to release itself and is, therefore, dangerous to that fragile membrane?

[spl23]

Originally Posted by harveyadam

If it is true that they do form an "air-tight seal" then surely no matter what level the volume is the pressure between the headphone and the ear membrane has nowhere to release itself and is, therefore, dangerous to that fragile membrane?

No, not at all. Your eardrum is subject to pressure differences all the time - that's how it works! When a sound wave hits your eardrum, that causes a momentary increase in air pressure on that side of the eardrum, which causes the eardrum to move and the volume of the sound you hear is proportional to the pressure. Your eardrum can't tell whether the pressure it experiences is due to a speaker 10 feet away or an IEM transducer 1cm away, and it doesn't really matter - the only real difference is that the transducer is only having to move a very small volume of air to get the same effect as the speaker moving a very large volume of air.

If you were to seal a bass driver in an airtight seal to your eardrum and turn that on then yes, you could massively overpressurise the eardrum - but the transducer in an IEM only moves tiny distances by comparison, and so it only introduces tiny changes in pressure.

[harveyadam]

Thanks to all who have replied to this post. It has been very interesting and enlightening reading your views.