**Hifiman HE-400 Impressions and Discussion Thread**
Dec 31, 2013 at 2:06 PM Post #15,586 of 22,116
@money4me247

People can decide for themselves if a headphone with a 92.5 dB/ mw sensitivity rating and a constant, non-reactive impedance can ever take "different amounts of power to reach the same volume," in the real world, and that decision will indicate whether they understand what I'm saying or not. I've already written enough to explain my position, so it's beyond my control at this point. It seems like most people here don't really care though...

deadhorse.gif

 
Dec 31, 2013 at 2:37 PM Post #15,587 of 22,116
   
 
 
My only issue so far is the headphone seems to be quite lose on my head.  I think i have kind of a small head but not abnormally small.  If I lean my head forward or back while wearing these they tend to slip quite a bit.  They don't completely fall off but come close.  Honestly as much as I like the sound the fit of these has me contemplating returning them.  I don't find the weight an issue.  They are quite a bit heavier than the 650's and 880's but not uncomfortably so.  I just don't like how much they move on my head.  Not sure if other people have noticed this or not...maybe just guys with small heads like mine.  
 
 

 
The solution for you is easy. No need to return them if you like everything but the clamp. The headband is made of metal and can be re-shaped to add or reduce clamp. Just be careful with where you put your hands when you bend the headband. Easy...
 
Dec 31, 2013 at 2:42 PM Post #15,588 of 22,116
Finally had some time this weekend to fix the one thing I don't like about these headphones, the cable.  The stock cable is way too long and stiff.  Had some teflon coated silver wire and made a cable.  I was actually surprised with the improved high frequency response.  I know it's been said that silver wire improves the highs, but I never really found any difference with my other cans, but it really makes a difference on the he-400.
 

 
Dec 31, 2013 at 3:28 PM Post #15,589 of 22,116
   
I hope that I don't come off as an ass as well, heh. I don't think that anyone else has in this thread, that's for sure. 
 
 
I looked at the ASUS website and they don't post power specs for the Essence One at all. That makes me believe they aren't pushing enough current for these drivers. I looked at the other options you have, and I think that none of them are ideal. The Crack with Speedball probably has far to high of an output impedance for these low Ω headphones which will make the headphones sound "boomy" and lose control of the bass. 

 
I hear ya. Well, heres some numbers to consider:
 
NuForce Icon HDP: 288mW RMS @ 30Ω SPECS
FiiO E09K: 900mW RMS @ 32Ω SPECS
ASUS Xonar ST: No idea.
ASUS Esscence One: 7Vp-p SPECS (which if my understanding is correct would mean at an impedance of 35Ω for the HE-400's P=V^2 / R = 7^2 / 35 = 1.4W @ 35Ω)
 
Im assuming the ASUS Essence One value of 1.4W is RMS too...
 
That being said I have been kicking around the idea of selling a majority of the Amp/DAC gear I have an picking up a Schiit Bitfrost and Asgard 2 combo. Any one tried driving the HE-400's with an Asgard 2? Supposedly 1W @ 32Ω
 
Dec 31, 2013 at 3:31 PM Post #15,590 of 22,116
@money4me247



People can decide for themselves if a headphone with a 92.5 dB/ mw sensitivity rating and a constant, non-reactive impedance can ever take "different amounts of power to reach the same volume," in the real world, and that decision will indicate whether they understand what I'm saying or not. I've already written enough to explain my position, so it's beyond my control at this point. It seems like most people here don't really care though...

:deadhorse:


I care and think you are right about this. The manufactures spec should account for their output impedance in their power rating.
 
Dec 31, 2013 at 3:52 PM Post #15,591 of 22,116
  @money4me247

People can decide for themselves if a headphone with a 92.5 dB/ mw sensitivity rating and a constant, non-reactive impedance can ever take "different amounts of power to reach the same volume," in the real world, and that decision will indicate whether they understand what I'm saying or not. I've already written enough to explain my position, so it's beyond my control at this point. It seems like most people here don't really care though...

LOL @manbear, you only think that people are beating a dead horse disagreeing with you because you are misapplying a basic high school physics equation to a problem that has more variables than that. no offense intended, but you obviously do not have the background or expertise in this field to continue throwing out your opinions out as fact. people more knowledgeable about the subject than you have been trying to explain the concepts to you, but from reading the thread, you've just been either ignoring or misunderstanding their responses.
 
For example, the statement about "a constant non-reactive impedance" in your above post is incorrect:
Code:
 Headphones impedance as specified by manufacturer is only *nominal* impedance, but actually, it varies with the frequency of the signal. Some headphones can have as much as double this value at certain frequencies. We call this value 'load impedance' , or 'Zl'
This concept was clearly articulated during that long-winded discussion earlier... In addition, other concepts such as the impact of the actual amplifier output impedance (Zs) on signal strength, primarily voltage-driven vs current-driven amps, etc were brought up and explained... your points were individually addressed and explained why the assumptions behind them were wrong...
 
I am certainly no expert in this field, but by simple reading this thread and a few other explanation threads, I can understand why claims you made in your discussion are simply incorrect. You are missing a lot of basic information, and you should really take the time to read the introductory post in this thread since you are so passionate about the topic: http://www.head-fi.org/t/607282/headphone-amp-impedance-questions-find-the-answers-here
 
Regarding your claim that output power the only measurement that you need: you can refer to this thread for further explanation: http://www.head-fi.org/t/552246/how-important-is-the-power-rating-with-headphone-amps
 
It is great to see that you are so interested and passionate about the subject, but please keep in mind, this is the HE400 discussion thread. Not the how do amps work thread. There are many knowledgeable people here who can further discuss that topic with you & clear up any remaining misunderstandings on one of those threads.
 
Dec 31, 2013 at 4:00 PM Post #15,592 of 22,116
Reminds me of that other heated discussion about whether or not electrostatic drivers can physically displace air. Gosh that was so stupid, misinformed people throwing around half-baked concepts.
 
Dec 31, 2013 at 4:41 PM Post #15,593 of 22,116
 
For example, the statement about "a constant non-reactive impedance" in your above post is incorrect:
Code:
 Headphones impedance as specified by manufacturer is only *nominal* impedance, but actually, it varies with the frequency of the signal. Some headphones can have as much as double this value at certain frequencies. We call this value 'load impedance' , or 'Zl'
This concept was clearly articulated during that long-winded discussion earlier... 

 
 Look at this Headroom graph. Do you see impedance changing with respect to frequency? 

graphCompare.php
 No offense, but I get the sense that you don't understand the information you're copy and pasting, as well as linking, at me. That snippet is true for dynamic headphones, but not for planars. Planars have no reactive component to their impedance, which is why it is constant with respect to frequency. Dynamic drivers on the other hand have voice coils, and those coils lead to reactance. Different physical construction, different electrical properties.
 
Post #2 of http://www.head-fi.org/t/552246/how-important-is-the-power-rating-with-headphone-amps is more or less what I've been saying all along -- as long as you are within the limits of your amplifier, power into the load of the headphones is the entire picture in terms of how "well-driven" they are. Output impedance, current limits, and whatnot all affect whether or not an amp can actually deliver the right amount of power into a headphone's load...

But if an amp can deliver enough power, then power is just power and that's all there is to it. The resistance of the headphone itself, not the amp, determines voltage and current at a given level of power. And that's power as measured across the headphone's drivers. Not whatever misinformed conception of power that is making it hard for you to understand how Ohm's law applies in this context.... Can you honestly tell me what these extra variables you mentioned are, and can you demonstrate how using these extra variables contradicts my statements? If not, please do not talk about background or knowledgeability. 

Here is a thread I started about this subject: http://www.head-fi.org/t/697974/volume-power-voltage-current-and-amplifier-output-impedance-in-planar-headphones#post_10123160
 
 
Dec 31, 2013 at 4:53 PM Post #15,594 of 22,116
  @Mingus Ah Um, I too have a small head. The easiest fix for this issue is simply doing some sort of headband cushioning mod where you add cushioning under the headband so that you "expand your headsize" lol.
 
there are many options out there. I personally would suggest trying the HD650 replacement cushions (available for $8 direct from Sennheiser) + velcro first.

 
 
   
The solution for you is easy. No need to return them if you like everything but the clamp. The headband is made of metal and can be re-shaped to add or reduce clamp. Just be careful with where you put your hands when you bend the headband. Easy...

Matt & Money...thanks for the suggestions.  I really do love these headphones and would prefer to keep them.  I'll work on some headband adjustments to see if I can get a tighter fit.  That would definitely be preferable to returning them.
 
Dec 31, 2013 at 5:21 PM Post #15,596 of 22,116
Man, all that rehashing old battles totally blew my question out of the pool.
 
Any of you out there driving the HE-400's with a Schiit Magni or Asgard 2 and care to comment? Both seem like they ought to be powerful enough at >1.0W @ ~30OHM.
 
Dec 31, 2013 at 7:36 PM Post #15,598 of 22,116
Been following this thread for a while. Just sent my Beyerdynamic 880 back to Amazon yesterday. Once the return is processed I will be ordering a pair of HE-400. Propably pair it with a Vali. So excited, can't wait. Thanks for all the info in this thread.
 
Dec 31, 2013 at 7:43 PM Post #15,599 of 22,116
 
I just got my HE-400s from headamp, but the left cup isnt working.  I tried 2 different amps and two different 1/4 to 1/8 adapters and w/o the adapter, and each time there is no sound out of the left cup.  Tried switching the L and R connections and still no sound out of left.  Hopefully headamp's RMA process is ok...

 

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