[leeperry]

what's your measuring device?

laptops are known to be very noisy because it's just too cramped in there, USB DAC with galvanic isolation should fix it.

 

[castleofargh]

aren't you guys discussing 2 completely different things mixed in one? when we talk about noisy stuff like a computer, it's noisy relatively to the audio signal, meaning it's usually a few magnitudes below the amplitude of music. and music itself on most gears is going to end up being a few volts in the audio band, so very low frequencies. that doesn't strike me as remotely dangerous.
a cellphone, a microwave, wifi, those are so much higher stuff when it comes to freqs, amplitude, energy... and the jury is still out on the health impacts thingy.
getting paranoid because we don't want noise in our music is a perfectionist issue. getting paranoid about waves and magnetic fields hurting us, is a completely different issues, different frequencies and different amplitudes. I guess people who are worried about that would avoid wifi, avoid keeping cellphones close to them when they don't need to, and maybe avoid headphones that require 150V in the cable to get comfy listening level(although I have no clue if it has any remote form of impact on the body). I'd consider those stuff to be one extra level above precautionary measures, and I fear that those who count that as dangerous will count so many other stuff as dangerous(most of it they cannot control!!!) and will have such a worried life.

 

[bigshot]

I can't imagine headphones being dangerous at all. If you put your phone in your pocket or your laptop on your lap... not likely but maybe. But if your comp is on the table and you're sitting a foot or two away, I can't see how that would be dangerous at all. But I don't know that much about the tolerances for this stuff.

 

[ev13wt]

I keep thinking about how we live in a universe made up of magnetic fields.
How much energy can a BT even transmit?

Yes, I turn on airplane mode at night. Hehe.

 

[Arpiben]

I can't imagine headphones being dangerous at all. If you put your phone in your pocket or your laptop on your lap... not likely but maybe. But if your comp is on the table and you're sitting a foot or two away, I can't see how that would be dangerous at all. But I don't know that much about the tolerances for this stuff.

Tolerances are around:
- Electrical Fields < 10V/m
- Magnetic Fields < 1microTesla.

Keeping devices at reasonable distance, >30 cm for example, significantly reduces EMF.
In laptop case, it seems that the main EMF contributor is the power supply PS (1.5kV/m). Therefore don't use the PS for warming your body

 

[leeperry]

No subs apparently but you might like that video:


Short story is that using a cellphone with a high SAR value while wearing glasses made of a metal frame might just be more hazardous than using headphones with a metal grill in front of the drivers.

 

[Phryq]

Radio Frequencies from cell phones etc. are carcinogenic among other things; if you want I'll link the relevant research.

My issue isn't radio frequencies, but electric fields, traveling through the computer into the headphones. You can see in this video.

 

[intika]

Very interesting topic .... @leeperry "those who speak don't know and those who know don't speak" true lol this is what forced me to register and post... but nevertheless the thread is rich with useful infos ... i do work on telecom engineering and on other telecom health related things. i was reading this thread because i am interested in getting a Stax headphone and was curious to know if they do pollute, thanks @Phryq who measured his magnetic headphone (i guess that Stax would behave the same as they use the same technology).

First thing first what's more important for the health is the electric field much more than the magnetic field, medical research proved the impact of electrical field on human cells plus exposure increase the temperature (proven) while the impact is less important for the magnetic field. (but it's not a zero impact we have to watch everything). In telecom in Belgium the law limit the commercial emission to 3V/m³ for cell tower etc (this was the main reason why providers did not get 4G quickly in Brussels, because of the density...) the limit is almost the same on all European countries the law is very restrictive it apply to phone etc. on idle state but does not apply when you are connected (Internet/Phone-Call) all phones exceed far the limit when they are used (not idle). any way the law apply to other devices as well, routers/headphone etc. other thing to know, i believe in Russia and some other country the limit is a joke and it's set to a very high level, so if you live on those countries make sure to test your devices because basically they are not controlled.

Very important: the video posted by @leeperry is a scam that made a huge issue in France they were pretending to reduce the cell phone pollution with patch, first time i saw that i was like ohhh i need one then thinking of it technically i was like hahahaha it's impossible this is a joke, and indeed sometime later the company were convicted and the product was removed; think of the electric field as a bubble you can indeed reduce or cancel the field in a closed environment (if you pack you phone in aluminum the phone will lose connection) but certainly not in an open manner like the patch, this could indeed reduce block the field just behind the patch (1mm or so) but it is all what it does; Basically the patch have no effect (for heavy users what i can advice is to use the wifi as much as possible and not on far location from the router. wifi pollute way less than 4g/3g etc..)

@Phryq you basically have an electric leak on your computer possible reason: 1. the adapter is broken. 2. the battery is broken, 3. the mother board is broken. plus the computer is not shield to the ground correctly or your ground shield is not good or not working properly (house's electric installation)... you can test with a different charger and without the battery if you can remove it, otherwise there are some other solution like explained on this video youtube.com/watch?v=GbNyINuo-Uw it should do the job, there are usb filters from china for 1 or 2 euros on ebay...

@Phryq you headphone is magnetic like the Stax right? can you please test it while playing music and at different volume level please (without the computer charger lol) thanks

 

[Arpiben]

@intika
Just to complete, I would like to add that Electromagnetic fields' values without frequency or frequency range specified are quite meaningless IMO.
The 3V/m Belgium commercial limit is excluding TV and radio FM broadcasters, worth to mention.
The regulators' upper frequency range is also quite large and vague (1/2 GHz - 300 GHz)...
Dealing with headphones the frequencies concerned are 50Hz/60Hz (+harmonics) and roughly 0-20kHz.

 

[jmills8]

 

[intika]

@Arpiben yes completely true but without real specific medical research, government can not do much; plus this require a lot of time to see the real impact on us so... lastly the sound waves frequency should not be an issue other than may be headache on high/low frequency for people with sensitive ear... but who know

 

[SilentNote]

Browsing through this thread I'm still not certain which type of electromagnetic field do headphones generate?

If it's a field that doesn't oscillate then the risk is much lower than an oscillating field that generates electromagnetic waves. And only high energy electromagnetic waves are a serious health risk.

Edit: after a bit more research, the electromagnetic waves generated by the oscillating EMF of headphones are of audible frequency... lesser than 30khz, which is considered low frequency EM waves (low frequency radio wave). At these very low frequency and energy levels, I highly doubt the risk of the EM waves generated by headphones.

The real risk of EM radiations are the ionizing radiations which start around 3PHz (petahertz). Radio waves do not cause ionization so their health risk is debated. Even if radio waves do cause health issues, the radio waves generated by headphones are of audible frequencies, at the very bottom of the radio wave spectrum. These have very low energy levels (<124 peV).

Honestly I think the health benefits of listening to good music from my headphones outweighs the risk of such low energy electromagnetic waves.