[dj_mocok]

ah, cellphones, without them (my bills), i would probably be able to buy CD3000 every 3 months...

hmm...now it got me thinking....

 

[TonyTripleA]

Perhaps I can provide a bit more perspective on this as I delve into this area for a living. A collegue has updated me recently as he is chairing a body doing several dozen studies in the mobile phone radiation area.

First: there is no definitive evidence either way of damage or no damage from electromagnetic radiation from mobile phones. This radiation is a non-ionising form of radiation and most consider it relatively safe. Ionising radiation like x rays breaks apart chemcial bonds which hold together important substances like DNA... so that's good.

Initial concerns over electromagnetic radiation came from a study in Sweden in the 1980s (if my memory serves me correctly). Slight elevation of cancers was found in people living under power lines. This study was redone to try and replicate the results. I don't believe anyone ever came to the same conclusion. But after some very complex analysis a relationship was found between socio economics and cancer in this first study's population. Turns out that there is support for the conclusion that lower socio economic grouping means more chance of living in cheaper housing under power lines and eating a diet which is more likely to cause cancer. So some conclude diet not electromagnetism is the cause of the elevated cancers.... hmmm, I'm not giving up beer though.

So how does this relate to headphones. Well, the electromagnetic fields are very, very low. A cell phone could be say one watt, headphones are in milliwatts. Under power lines there can be so much power that when I used to study in a high tension lab we used to light up florescent tubes just by bring them into the lab, he, he, he. I still light up my LED bicycle light by placing it next to my mobile phone and getting someone to ring me... lotta fun.

So far so good.

Second: The frequency of electromagnetic radiation determines its energy or in this case potential to cause "effects". Cell phones are many, many times higher in frequency than what would be pulsing through headphones (which I assume would just be 5-50,000 Hz). Once again no worries here.

So far so good again.

Third: Magnetic fields are used in industry to disinfect water by disrupting the cell membranes of microbes. This is done by disrupting the ion pumps (for example Na or Ca ions) which operate in cell membranes. A vital mechanism. But magnetic fields capable of doing this are massive. Headphones are using very small magnetic fields, for limited times.

So far even better, but I'm not sure I'd go out and buy those magnetic bed liners and sleep on them.

And just remember, anxiety DOES cause cancer... well documented...

Cheers,

TonyAAA

 

[bhd812]

well I think its a fact that headphones cause a pressure on your entire ear,,,,,which of coarse leads to the brain.


sereious, on every set of headphones I have destroyed only the left ear blows and not the right...why?


pressure my friend

 

[Wodgy]

TonyTripleA, you're either not up-to-date or simply misrepresenting recent science. As I mentioned in an earlier post, cell phone radiation is non-ionizing, but that's wholly irrelevant -- it's not the manner in which cell phone radiation has been shown to disrupt intracellular activity. Microwave radiation has been shown to have a demonstrable thermal effect on intracellular nucleic processes.

As for lower frequency electromagnetic radiation, there has been more research than just a "study in Sweden in the 1980s". The claim you use to dispute the early Swedish results (that they may have been reflective of socioeconomic factors) has been debunked by more recent studies in Toronto and Britain (link ) which controlled for socioeconomic factors. Even the US government (famously slow in adopting any kind of safety regulation if the jury is still out) has adopted safety guidelines for low-frequency fields (link) because, in their words, "some epidemiological studies have suggested increased cancer risk associated with estimates of [extremely low frequency] magnetic field exposure." European guidelines are tougher, obviously.

The only serious question is not whether low-frequency EMI is dangerous (it can be), but whether headphone use produces electromagnetic fields that exceed safety guidelines. That's hard to say without published measured data. However, the Ultrasone website says this:
"In a research sample of 60 current headsets (1999 - 2000) ULTRASONE found out, that the average magnetic field emissions of headsets is more than 1000 nT with a peak maximum of 2100 nT - on average this is more than four times the maximum, recommended for computer screens in TCO '99, in extreme cases more than ten times the maximum."

 

[fewtch]

So what's the point of this thread, that we should moderate headphone use because they can be dangerous? Oh, please...

 

[Vitalstatistix]

Thanks Wodgy and TonyTripleA for the technical discussions.

fewtch: there really is no other point of the thread besides me trying to understand something better to satisfy my own curiosity. I'm not trying to troll, or stop people from using headphones. I can't stop audiophiles even if I tried.

 

[TonyTripleA]

Wodgy: Very interested in the Ultrasone statement. Especially the comparison of headphones to CRTs, CRT standards have changed a bit since 1999 but it raises the question all right. Next time I am getting some EMF fields measured I'll ask the techs to do some measurements on my own cans just to get some numbers "in situ". If we are really going four times over "average" guidelines that would be enough to concern me.

(Edit: Warning the rest of this post is bordering on rambling, nah, its rambling...)

Aplogies if I was misleading or ill informed. I certainly didn't mean to misrepresent science. Findings on microwave radiation are not relevant to headphones, sorry if I implied they were (I was trying to emphasis that other radiation was perhaps not yet proved to be dangerous but this is as you say irrelevant to the real question concerning headphones). This is a very complex subject and I am generalising so you are right to put me back on track. There are certainly studies which would indicate positive findings on "high intensity" low frequency EMF, including the ones you cited. But the studies you cite are for relatively high intensity fields. I do believe that the jury is still out on just what might be considered low or safe levels of low frequency emf... and the question for us is: what does this mean for headphones? Am I right in guessing that the studies referring to high intensity fields causing leukemia would necessarily be effects associated with bone marrow irradiation and not relevant to headphones worn in the customary position? Are any other effects (cancers) known?

What I did mean to imply was that I do not believe an overall consensus has been reached and I should add the caveat "for low/moderate intensity low frequency EMF". The Swedish study is of historical interest only as an example which kick started the research which we currently debate. It is of relevance to us as headphone users as it related to low fequency EMF. The debunking of a finding in the original Swedish study is however recent and conclusive (I'll see if I can find some references) and it is this "finding" and "reversal of findings" that I find interesting.

I ignored thermal effects from radiation as these are unlikely from headphones (although the MS-pros with some Led Zeplin... he he he).

Nothing to do with headphones but... the most interesting report I read was that modulated FM radio frequency at high amplitude was shown to alter primate behaviour (in monkeys). Might have been some bad music but it makes you consider?

I'll see what interesting references I can dig up tomorrow that might be directly of interest to headphone users when chained to the desk.

A facinating topic.

Cheers,

TonyAAA

 

[acs236]

I think the only need that we know does not cause cancer is saccharin.

 

[wctkdman]

I don't think they could cause any damage, other than if they were set at too high of a volume. Sure there is some EM field around the driver, but it would be insignificant relative to the stuff you are bombarded with daily.

 

[petery83]

I'm 20 right now, I'll report back to Head-Fi in oh, say, 60 years if I develop brain cancer, but until then,

As of now, the only detrimental effect my cans have had on my health are when I've passed up food/going to the gym/going running to listen to music

 

[MD1032]

AAAAHHHHHHH!!! MY BRAIN IS DEVELOPING TUMORS!!!!!

Wow...this sure is a nice recording, though...

 

[w00t]

A case where magnetic fields have been shown to CAUSE "tumor-like protuberances" in a biological organism.
http://www.ncbi.nlm.nih.gov/entrez/q...t_uids=8986364

Note however that the test organism is a planaria, a simple flatworm that is quite different from humans and the test is performed while the organism was regenerating (and thus the conditions in the cells are much different than during "normal" life).

As for the aforementioned epidemiological studies, I'll put more trust into them once they actually do controlled tests on test animals. Correlation does not always imply causation. There are simply way too many confounding factors in epidemiological studies. Power lines are often found near roads, which logically would result in higher long term exposure to carcinogen-laden car exhaust, etc. Government regulations aren't always the best source to look for scientific truth as they are often determined through political maneuvering. I'm not saying those studies are wrong, but currently I don't see any data supporting the definitively supporting the claim that ELF magnetic field exposure causes cancer in humans.

Did a quick search on NCBI and found the following:

http://www.ncbi.nlm.nih.gov/entrez/q..._uids=15115289

Mice exposed to a 50/60Hz magnetic field showed decreased neointima (apparently some sort of lining in blood vessels) after 1 week, but any differences were gone after 2/3 weeks of exposure. 2 other parameters studied showed no difference between the two groups of mice.

Other links:
http://www.ncbi.nlm.nih.gov/entrez/q..._uids=15018215
The journal Bioelectromagnetics
http://www3.interscience.wiley.com/cgi-bin/jhome/34135

I would say the evidence is mixed for magnetic field causing cancer. Certainly there are cases where very exposure to very strong magnetic fields or exposing a developing organism to magnetic fields can cause problems. But personally I worry more about damaging my eardrums/hearing than getting cancer whenever i put on my ATH-A900s.

 

[eMpAtHy]

Quote:

I'm 20 right now, I'll report back to Head-Fi in oh, say, 60 years if I develop brain cancer, but until then, As of now, the only detrimental effect my cans have had on my health are when I've passed up food/going to the gym/going running to listen to music

ill be back in 60 years and let u guys know too