[yepimonfire]

I'm curious if it does and if so to what extent. Reason i ask is because i recently purchased a Behringer UCA202 audio interface, and just now found out it has an output impedance of 50ohms. Plugging my 34ohm headphones back and forth between the UCA and my ipod (which is rated at 5ohms output impedance) i'm not so sure i heard a difference. The only clear difference was a major improvement over my phones output and my laptops output, which was literally night and day. An even bigger difference was noted when going back and forth between my phone and the UCA with my 16ohm etymotics. Actually the etymotics sound fantastic out of the UCA, they sound like crap out of my laptop and phone in comparison. Based on the fact the output impedance for the UCA is 50ohms, (which is probably higher than both my phone and laptop) shouldn't it be the other way around?

 

[K_19]

One of the main symptoms of low impedence headphones/high output impedence combination is exaggerated, loose bass.  As Etymotics are extremely flat-sounding IEM's, it may be that bass area boost/decay that you are enjoying. But what you are hearing is likely not what the people at Etymotic Research intended for their customers to hear.
 
Find a low output impedence amp suitable for IEM's and give it a listen out of that.  If you don't like the sound of your etymotics out of those, then it's quite possible that you like more bass than what is neutral as seen on a graph (and there is nothing wrong with that if you do of course).

 

[yepimonfire]

Quote:

One of the main symptoms of low impedence headphones/high output impedence combination is exaggerated, loose bass.  As Etymotics are extremely flat-sounding IEM's, it may be that bass area boost/decay that you are enjoying. But what you are hearing is likely not what the people at Etymotic Research intended for their customers to hear.
 
Find a low output impedence amp suitable for IEM's and give it a listen out of that.  If you don't like the sound of your etymotics out of those, then it's quite possible that you like more bass than what is neutral as seen on a graph (and there is nothing wrong with that if you do of course).

actually the bass leaned out and the highs came out better in the UCA, the phone/laptop had loose uncontrolled bass and messy sounding highs. perhaps the outputs of the laptop/phone are just REALLY bad. i ordered a fiio e17 and i'm gonna give that a try. 

 

[Headdie]

It makes a difference, but sometimes it's what you want.
My K701 sounds great out of my NAD 220 ohms output jack,
while it sounds too lean out of my 0.05 ohms headphone amp.

 

[mikeaj]

For many headphones, it makes little difference.  Furthermore, the kind of change depends on the headphones.  Any kind of recommendation or rule regarding output impedance is just a recommendation.
 
Most of the Etymotic 16 ohm IEMs have much higher impedance at higher frequencies.  So it could be 16 across the range and then increases from roughly 2 kHz to about 80 ohms at 20 kHz.  Or something like that.

 
By some simple calculations (note: the source output impedance forms a voltage divider with the headphones, and you're interested in the proportion of the voltage of the source that's actually seen across the headphones), you can see that this means that with higher output impedance, you will get more treble relative to other frequencies—with the above-described IEMs or anything with a similar impedance vs. frequency plot.  What happens is that other frequencies are attenuated by a greater amount.

 

[yepimonfire]

Quote:

For many headphones, it makes little difference.  Furthermore, the kind of change depends on the headphones.  Any kind of recommendation or rule regarding output impedance is just a recommendation.
 
Most of the Etymotic 16 ohm IEMs have much higher impedance at higher frequencies.  So it could be 16 across the range and then increases from roughly 2 kHz to about 80 ohms at 20 kHz.  Or something like that.

 
By some simple calculations (note: the source output impedance forms a voltage divider with the headphones, and you're interested in the proportion of the voltage of the source that's actually seen across the headphones), you can see that this means that with higher output impedance, you will get more treble relative to other frequencies—with the above-described IEMs or anything with a similar impedance vs. frequency plot.  What happens is that other frequencies are attenuated by a greater amount.

thanks. very helpful. if i were to somehow add more resistance inline with the headphones, would that effectively solve an impedance problem? such as damping issues etc.

 

[Armaegis]

Not really, though if you have noise issues it might help with those as it will attenuate everything.

 

[yepimonfire]

well i got my E17 today, massive difference. frequency response remains largely unaltered however the sound is SUBSTANTIALLY tighter (only word to describe it). another thing i noticed is i can turn the volume up very very loud with absolutely no distortion.