32ohm vs 250ohm vs 600 ohm headphones, need help on choosing Options

[aaronius]

Ok, I'm just getting my feet wet into this audiophile stuff. But, I love my music and want to hear in the best way possible that I can afford. I have found a really nice pair of headphones that fit my budget.
However, they come in 3 different OHM's. I can get the Beyerdynamic DT 990's in 32 ohm, 250 ohm, 600 ohm. From what I understand the 32 ohm doesn't require a seperate headphone amp
and can easily be driven by a pc or mp3 player. (I'll mention that all my music is in AAC 256kbps. Not quite lossless but still much better than standard 128 kbps mp3.) But the 250 ohm and 600 ohm do need an
amp to get the best out of them.

My questions are:

1) how much better sounding is the 600 ohm over the 250 ohm over the 32 ohm? If any?
2) Will an inexpensive headphone amp like the Fiio E7 or E11 drive the 250 ohm enough to get the sound I paid for?
3) I plan on using these on my desktop computer for music (rock/metal) and gaming. Am I better off with the 32 ohm or is it worth the extra expense to get a cheap amp for the 250 ohm?

I appreciate the educated feedback as I am a complete noob and need help on this.

[saratoga]

That tiny difference is probably due to the limitations of the headphone amp, not the headphones. Higher impedance == lower load on the amp == (very slightly) less THD.

[IgorC]

That tiny difference is probably due to the limitations of the headphone amp, not the headphones.

The distortion introduced by headphones is much higher than one of amp's.
The transducer will always have higher distortion than electric/electronic circuit.

Example:
Headphones HD650 - THD 0.05% = -66 dB
Headphone amplifier of audiointerface E-MU Pre Tracker - THD+Noise 0.00175% = -95 dBA

http://www.sennheiser.com/sennheiser/home_...adphones_009969
http://www.ixbt.com/proaudio/emu/tracker-pre/2444.shtml

Higher impedance implies less distortion in this particular case (DT990). http://www.headphone.com/buildAGraph.php?g...pare+Headphones

I'm not sure I would read too much into that. The highest harmonic peak is down more than 60 dB.

60dB. Is it much or not. It's relative. Apple cheap stock buds have noise at -40 dB. Is it much?

This post has been edited by IgorC: Feb 17 2012, 17:39

[saratoga]

That tiny difference is probably due to the limitations of the headphone amp, not the headphones.

The distortion introduced by headphones is much higher than one of amp's.
The transducer will always have higher distortion than electric/electronic circuit.

Not necessarily. The distortion introduced by the amplifier depends on how good it is, and the load applied.

Example:
Headphones HD650 - THD 0.05% = -66 dB
Headphone amplifier of audiointerface E-MU Pre Tracker - THD+Noise 0.00175% = -95 dBA

Those are 0 load measurements. The distortion introduced by an amplifier is approximately proportional to the load. As you noted, at zero load there is essentially 0 THD. Try those measurements again with a 16 ohm load. Then an 8 ohm load. I bet THD is >>1% then

60dB. Is it much or not. It's relative. Apple cheap stock buds have noise at -40 dB. Is it much?

-60dB is basically irrelevant.

These two statements have a very little sense together.

Higher impedance will introduce less load on the amp, but its ridiculous to imply that distortion 60dB below peak (or even more!) equates to quality. Its basically irrelevant compared to the performance of the headphone itself.