[Zayus]

I recently ordered these IEMs, was just looking through their specs (eagerly awaiting their arrival) and noticed they had an input power of 350 mw
I'm used to seeing IEM's with 40-60 mw, and I generally don't understand electricity very well, but I assumed that the rating bassically meant that that was the input power they could handle without mechanically or thermally breaking, much like a speakers max input wattage.
So, why are the Eterna's input power nearly 10 times greater than the average IEM's?
does this have something to do with being able to handle portable amps?

I'm curious also, my friend goes through IEMs every 6 months because he literally blasts them constantly on max volume. would these be better suited for somebody who likes to pump so much power into them?

on a side note, I just gave this friend a brand new pair of Brainwavz M2 which are rated for 40 mw max input; should I advise him to take it easy on the volume? Don't know the output power of his MP3 player atm.

 

[Zayus]

I'd really like to know the answer to this.. sorry if bumping one's own thread is in bad taste here.

 

[dan1son]

Yes 350mw max on a headphone is a lot.  The iPods usually claim to be able to put out 30mws per channel to give you an idea. 
 
The sensitivity spec on that phone is 110db... that's usually measured with 1mw going into it.  Double the power to add 3db and you end up with a max volume of about 143db.  That's about the volume of a gunshot. 
 
Even an iPod on that phone at full volume will be pushing about 124db, FAR beyond what's considered safe at a small exposure.  Be careful! 
 
 
These would probably be good for someone who cranks it, in so far as they won't damage the headphones as easily.  HOWEVER more goes on at max volume than just more power.  Their will be distortion which can cause the headphone drivers to move erratically and outside of their specifications, which is probably what's breaking his so quickly... not their power handling abilities. 
 
A lot of things go into their ability to handle power... one of the big ones is heat dissipation.  That back metal piece might be a heat sink...
 
 
You should advise him on lowering the volume because of sound exposure, not because he's breaking his headphones. 

 

[Zayus]

I'm still not sure why they have so much more mw input than the others
would you know what physical difference there is between a 60mw and a 350mw IEM?
I wouldn't ask if the difference was miniscule, maybe 10 or 15 more mw, but 350 is off the charts compared to every other IEM I've looked at.

and about clipping, that's one thing I've never fully understood about audio-systems
for example, in a stereo speaker setup, clipping will occur when you try to drive your 175w speakers with a 50w amp
if you crank that 50w amp to max, it's going to try to put out some convoluted number of watts far exceeding 50 and drive your speakers into terrible clipping.
So how would you ever know how many watts you're pushing through your amp? the gain isn't actually printed on the volume knob.

in the same case with these earbuds, if I drive them with an ipod at 60 watts but they call for a max of 350, how do I know the earbuds won't try to up the output beyond 100 mw and push themselves far into clipping just as a bad speaker setup would?

 

[dan1son]

There are two things that can "clip."  The speakers can clip, which is usually a result of the driver physically running into something when pushed too far.  If the power is higher than they can handle it's possible that the driver actually hits part of the speaker enclosure (headphones almost have moving drivers, so that's still possible).  Usually drivers clip with bass notes since they physically move the driver farther than high frequency notes will. 
 
Also the amplifier can clip.  This happens when the amps output runs out of gas.  Basically the signal will "clip" and cause a note that's supposed to be a clean sine wave actually turn into a square wave at the top.  Some amplifiers, when clipped, get very erratic and can cause the signal to spike in all kinds of weird ways which is why a low powered amp can damage a speaker even if it's "capable" of handling more. 
 
The max power handling has nothing to do with the headphones inherent ability to pull more power.  And also remember 1mw is 110db on that phone... 110 db is quite loud.  It's unlikely you'll be pushing more power than that into them and not being in physical pain .  http://www.iill.net/decibel-levels
 
I don't know about you, but I wear hearing protection when I run my lawnmower or chainsaw.  I'm sure as heck not going to pump my headphones that loud. 
 
They just put the max power input because they test it... also they all test it differently (there's no standard for it).  That might be the peak before they just fall apart... others with a 60mw rating might be RMS so they have to run like that for a while before falling apart.  You just can't be sure. 
 
The important number is the sensitivity anyway.  You want to know how efficient they are.  110db at 1mw is quite efficient.  The HD600, for example, has a sensitivity of 97db at 1mw... they need a lot of power to get up to volume which is why you can't plug them into a portable system and expect much volume.