Aftermarket cables may also make a difference.  I'm sure more detail, and transparency can bee drawn out of the HE-500 with a OCC silver cable.   Likewise, a copper cable may help the midrange of the HE-6.
 
I prefer to work with a slightly darker headphone and liven things up with the electronics and cables which are driving them rather than darkening an overly bright and thin sounding headphone.
 
Over about 10 years of being involved with high end headphones including the Stax SR-007 and SR-009 and HE-90, and R-10, and qualia,  I can clearly say I do not like bright headphones.  I like neutral to slightly dark headphones which have stronger mid's and bass response combined with crystal clear and transparent electronics and cables behind them.  It's what works for me.  I prefer to give a wake up call to the darker headphones than to tone down the bright ones.  To my ears the sound is more balanced and convincing making the tweaks this way.  That is my experience.
 
The LCD-3 is a great example.  It is way to dark in it's standard form and somewhat lifeless.  However using silver IC's throughout my system and a replacement silver occ cable on the headphones, - to my ears- it is just right- dead neutral and tonally full.  The difference using silver vs. copper in these areas makes all the difference to me. Very substantial in audiophile terms.
 
I have not heard the HE-500 or HE-6, but from what I am reading combined with my experience in the past, the 500 is the way to go.  I am willing to bet that if I really wanted them to obtain that last 5%-10% of clarity and transparency that the HE-6 has, a silver cable will do it or at least get me so close that it won't matter- without giving up on the naturally better midrange and tonality of the 500. 

I can't argue the cable point as I don't have experience with them and personally I'm a 'cable sceptic', in the sense that I think a normal, good quality cable should suffice.  I've so far heard the HE-6 with my cables (toxic cables, they came with the phone), the stock cable and (at a friends' place) his version which were cabled with some super expensive cable (cost as much as the headphones itself, don't recall the brand, think it was something Japanese).  Anyway, if there was an audible difference I didn't hear it.
 
I don't think you could coax the HE-500 to reach the same point as the 6 regarding transparency and detail, true, the difference might be 5-10% but those last % (in anything) are usually harder to accomplish than the 95% first (diminishing returns).  Plus, the cans have a different membrane structure.  For the extra cost price of the cables you might be better off just purchasing the HE-6 straight away if that's what you want.  I switched back and forth between the 500 and the 6.  Still think the midrange on the 500 is better but at present and certainly regarding transparency, detail and treble the 6 take the cake home.  Just my opinion owning them both but as I said, I'm no cable guy.

Interesting.  Many people claim cable changes make minimal improvements.  I tend to think people exaggerate sonic improvements on Head-fi in general as well.  However- in this instance- my upgraded cable for my LCD-3 is so dramatically better than the stock to my ears- it nearly sounds like a different headphone.  I can't believe I am saying this and I don't want to contribute to the exaggeration I was just referring to- but I really feel that way.  I would imagine these same dramatic results (to my ears) will occur if I switch the HE-500 cable but I am waiting arrival of the used HE-500 I ordered any day to see what it sounds like with the standard cable.
 
Either way- if the HE-6 smacks of SR-009 style transparency which many have suggested, the treble range will be a price to high to pay for the 5%-10% improvement in other areas.  I owned a BHSE and very very much preferred the 007 to the 009.  The 009 wins technically hands down- but the actual listening pleasure over time goes to the 007 by far.  My hunch is the same regarding the HE-500 and HE-6.  I have seen just to to may complaints about the thinness and highs of the HE-6 to take the risk even if many of those complaints were base on underpowered amps driving them.

HE-6 Thin?  Not hardly..

rsbrsvp said:

  Interesting.  Many people claim cable changes make minimal improvements.  I tend to think people exaggerate sonic improvements on Head-fi in general as well.  However- in this instance- my upgraded cable for my LCD-3 is so dramatically better than the stock to my ears- it nearly sounds like a different headphone.  I can't believe I am saying this and I don't want to contribute to the exaggeration I was just referring to- but I really feel that way.  I would imagine these same dramatic results (to my ears) will occur if I switch the HE-500 cable but I am waiting arrival of the used HE-500 I ordered any day to see what it sounds like with the standard cable.
 
Either way- if the HE-6 smacks of SR-009 style transparency which many have suggested, the treble range will be a price to high to pay for the 5%-10% improvement in other areas.  I owned a BHSE and very very much preferred the 007 to the 009.  The 009 wins technically hands down- but the actual listening pleasure over time goes to the 007 by far.  My hunch is the same regarding the HE-500 and HE-6.  I have seen just to to may complaints about the thinness and highs of the HE-6 to take the risk even if many of those complaints were base on underpowered amps driving them.

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Yeah thin is the last thing the HE-6's are. If you hear the HE-6 and the HE-500 side by side, assuming the HE-6's are properly powered, the HE-6 is something else altogether. 

lljayll said:

  Yeah thin is the last thing the HE-6's are. If you hear the HE-6 and the HE-500 side by side, assuming the HE-6's are properly powered, the HE-6 is something else altogether. 

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Yes, different flavors, same classification.

austin morrow said:

   
Yes, different flavors, same classification.

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To your ears maybe but not to mine.

It are not the same headphones, simple as that.  Both are very good quality, both have their stronger and weaker points, for some properties I prefer one over the other.  I was/am still a bit on the fence and that's why I keep 'm both.
 
Positives (my appreciation, short version):
 
HE-500:  Easier to drive, voiced to deliver a warmer, more earthly sound overall.  Extremely good midrange, fast.  More tolerant of imperfect source material.  Cheaper than the 6
HE-6:  Very neutral, very clear/transparant, tremendous overall performance.
 
Cons:
 
HE-500:  Not as clear/transparent as the HE-6, treble not quite as well developed (in the eye of the beholder....)
HE-6: (relative disadvantages) very power demanding and you need a setup that's more specialised to specifically the 6 to get the absolute best out of them, I wouldn't say thin sounding but treble sometimes a tad aggressive, more expensive but imo still a bargain compared to the ex-hifiman competition.
 
As I said previously, the 500 reach to 90-95% of the HE-6 imo but I concede that those last % do make a difference.
 
I listen to classical and with some works I prefer the 500 over the 6, with others the other way around.
 
I'd say:  if you like to relax in your easy chair with a whisky and enjoy jazz/blues--> my preference would be the 500.
If you like listening to rock/electronic music, go with the 6.
 
For classical (my alley) it depends (recording quality, dynamics of the piece, mood....).

Xenophon, out of curiosity what are you using to power your HE-6?

Dac is the Violectric V800, signal goes via XLR to a V200 amp.  Sounds very good to me (and also works with my other cans).  It outputs 2750 mW into 50 Ohm and that's certainly enough on paper (manual specifies using an amp that can deliver min. 2W).    My volume is typically at  11-12, V200 set to +6dB gain.
 
The other setup I use is the V800, via RCA into a dark voice 337 dual mono tube amp, using Tung Sol 5998 power tubes and RCA 'red hots' drivers.   The builder of the 337 doesn't specify power output and there are different versions out there, I purchased mine from a member who also purchased it used from a person who had modified/customized it.  Anecdotally, the 337 builder mentioned in an interview that one of the cans he used as a reference was the AKG K-1000.  All I can say is that it sounds extremely good (no one was morte surprised than I when I tried it).  The bass is a bit less tight than with the V200 but a -imo positive- side effect is that it takes down the sometimes harsh treble a bit.  Also, it's a tad -but not much- less transparent than with the Vio but that's a tube amp for you of course.
 
One caveat for the sake of intellectual honesty:  I've been in an ongoing discussion with preproman who takes the view that in order to get the best out of the HE-6 you really require a speaker amp.  I don't know, am going to try it out and suspend judgment until I did.  But if you go the speaker amp route it's imperative to make sure that the pairing is good, I've heard it a couple of occasions on speaker amps and there the quality was definitely less than with the Vio.

As with just about anything - "quality does matter"  So yes the amp will matter.  Just like you can't stick any old headphone amp on the HE-500, you can't stick any old speaker amp on the HE-6.
 
I've owned every HiFiMan in production, excluding the HE-300.  I never owned the HE-400 but had them in house for a few months on two occasions. 
 
Towards the end I kept the HE-500 and the HE-6.  I did this because these two were the ones that sound the most different, not because I like the HE-500 better than all the others.  At the very end I could not deny technicalities and the Sound Quality of the HE-6.
 
For classical music - Large orchestral or chamber, I would never in a life time pick the HE-500 over the HE-6, just no.  Jazz Vocals and small jazz trios I could see why someone could go with the HE-500.  However, the HE-6 excels in this as well, IMO even more so compared to the HE-500.  
 
Being really picky here - splitting hairs - while the voices really does sound good on the HE-500 - I mean fantastic.  The voices on the HE-6 are just cleaner more clear, the bass is more accurate from mid bass down to sub bass.
 
I would agree 100% with the pro and cons above.  Never would I say in one million years the HE-6 are thin in any area.
 
Here's how I would rank them.
 
HE-6 --> HE-5LE --> HE-500 --> HE-4 --> HE-5

The HE-6, thin?! That would just about take the cake as the most ridiculous thing I've seen on Head-Fi (and that's saying something).

nztechfreak said:

The HE-6, thin?! That would just about take the cake as the most ridiculous thing I've seen on Head-Fi (and that's saying something).

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+1

xenophon said:

 
One caveat for the sake of intellectual honesty:  I've been in an ongoing discussion with preproman who takes the view that in order to get the best out of the HE-6 you really require a speaker amp.  I don't know, am going to try it out and suspend judgment until I did.  But if you go the speaker amp route it's imperative to make sure that the pairing is good, I've heard it a couple of occasions on speaker amps and there the quality was definitely less than with the Vio.

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When I first tried the HE-6 out of a schiit mjolnir, I didn't like it at all and even liked the HE-500 more out of the same amp. The mjolnir is one of the most powerful headphone amps out there and it still does not bring out the HE-6 like a 100wpc integrated amp. I have also done A/B testing with this setup and the difference is night and day. 
 
When you try the HE-6 out of a speaker amp it is just a different headphone. I wasn't a believer until I heard it for myself.  

lljayll said:

  When I first tried the HE-6 out of a schiit mjolnir, I didn't like it at all and even liked the HE-500 more out of the same amp. The mjolnir is one of the most powerful headphone amps out there and it still does not bring out the HE-6 like a 100wpc integrated amp. I have also done A/B testing with this setup and the difference is night and day. 
 
When you try the HE-6 out of a speaker amp it is just a different headphone. I wasn't a believer until I heard it for myself.  

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Sorry but that depends on the headphone amp and speaker amp in question, it's not a gimme.
 
I have heard a number of typical amps from Rotal, Nad, Cambridge Audio, Yamaha, Marantz etc up to £600 and none have been better than my Master-6 driving the HE-6's.
 
I fully expect better speaker amps to be better with the HE6, if synergy is good, but to say that the HE-6's are going to sound better just because it's being used on a speaker amp is just wrong.