Hate to wreck the FR discussion but similar frequency responses can still yield different tonal perceptions.  Anyone w/ a decent amount of amp AB experience can tell you all about the different sounds of flat/linearity.

Sighted listening is evil. Don't do that when comparing something that sounds so similar as DACs and amps and when it's not necessary. Do calibrate voltages as well. Do check output impedance too.

If I hear anyone saying "amp A is better than B, because I did a sighted uncalibrated listen with headphones having non-flat impeddance" (or other unqualified statement), I'll do this: 
The perpetrator then will be shot and quartered.  (if I manage to meet them in person that is)

Pity double blinding is not really possible in terms of headphones not of the same brand and make.

The other fun part is that well made amps and DACs do indeed sound so close with easy, they're neglible. However, give them a hard CIEM load or a current hungry ortho, the situation changes.

This is how I see it. Just want to confirm the general opinion around this forum so I don't jump ship...Which of these statements, if any, are false:

G)This is one sad state of affairs. ..... With the remaining $500 I saved from not buying LCD's and headphone amps, I can put a pretty sweet stereo in that car that sounds great and doesn't have the issues that seem to plague headphone technology 

H)who would have thought that reproducing music through headphones without annoyance would be so difficult in 2012. 

My personal opinion (i.e. not the truth)

A through F: is just a personal opinion, but in general thoughts I could agree, coming from the angle we are looking for TOP performing headphones.
G: Get that car sound-system into a room next to a good hifi setup and see (hear) what flaws it has... the love for the car has 'set' your mind in pleasant mode.
H: It's quite simple really, as said the perfect headphone doesn't exist because of (electro)-mechanical properties of the materials used.
Also what sounds perfect to person A may sound moderate to person B.

There is a big problem (even with blind comparisons of headphones) and that is one get's used to a certain presentation.
It is NEVER really a flat reference but your brain might perceive it that way, certainly after a period when we have gotten used to its presentation.
When you put on the next headphone you instantly hear the differences COMPARED to the one you listened to before... e.t.c.
when comparing A, B and C headphone you are entering a wasp nest of 'objective comparison problems'.
Yes, even the most experienced listeners are still affected  . (I don't consider myself one of those)
True they can perhaps more easily and faster hear very (obvious) things that are wrong, but ears, brain and preference are still in the mix.

Some people are really satisfied with their 'very neutral' HD201, which isn't neutral and accurate compared to other HP's but most certainly can be perceived that way by owners (not me).
Does that qualify as the 80% of bad headphones in this case when people love it (the 'neutrality') ?

flat and accurate (as possible) is just that... but to whom ?

The satisfied listener...

Indeed.... for now... untill the flaws slowly start showing or I get a wake-up call ... 

regarding the hp, some things to consider....

Maybe the only reason LCD's flat line doesn't sound thin is because the planar technology is artificially thick (or thick by its nature). Maybe that's why it sounds odd as somene mentioned in another thread, it's thin and thick simultaneously.......

the hp went out of production ......... were they made with some exotic material that is no longer found on the planet? or involving some labour intensive aspect?  did they not sell?  in any case, phones like them that can span all 3 categories (i'll bet there are phones better for electronica fwiw) are rare and pricey imo which gets us back to my original thesis. There are a few excellent phones out there..... Isn't the hp the phone symphones was modeling with it's driver and alum chambers..........

Regarding the LCD-2, I seem to recall that was one of purrin's inspirations for starting Changstar: the graphs that Audez'e included were rather deceptive and showed them as being much flatter than they actually were. Like, after applying smoothing and whatnot it makes the LCD-2 look ruler straight when it's not anything close to being neutral. There do seem to be qualities to sound however that are difficult to convey with measurements, like the specific tonal quality piezoelectric film has (as in the H2+). It's a subtle quality that I find difficult to really articulate, but no other driver technology I've experienced reproduces the same effect. Similarly orthos do often sound thicker than electrostats by nature, but I have heard some 'stats that can rival the LCDs for bass: namely the Jades and new Float QA. Still, what fascinates me more personally are spatial characteristics and how one could account for them using measurements.

I'm no expert on Grado history (read: devouringone), but my understanding is that when John took over the company from Joe, he still used Joe's HP drivers in his headphones for a while (SR100 and 200?), but eventually switched over to his own. I guess it was a matter of convenience, but I also suspect it was to distance himself and his creations. I definitely find some legendary headphones more deserving of their reputation than others. The L3000 is an instance of an overall really bad sounding headphone (IMHO) that gets put up on a pedestal because of its rarity and beautiful craftsmanship. The R10 on the other hand is a sonic marvel, but I still think it's overrated due to its exuding a veritable sacred aura.

Personally, I think the best value for money is in vintage electrostats (and orthos if one is willing to put in the work to tune 'em up to spec). Perhaps it sounds like an exaggeration, but I feel a pair of vintage Lambdas can stand up to the vast majority of $1k+ on the market today. Same with the Koss ESP 950, which is getting on in years. I don't think we've come very far compared to where we were 30 years ago in full-sized headphones TBH.

I fall back on transparency to give me a window onto music. Sometimes I just want the headphones to get out of the way. Ringing, bloated bass, and treble razors aren't enjoyable. Still, I happen to like a lot of highly-colored headphones which are often quite polarizing. Exploring different colorations can be fun, and sometimes these influence music in a pleasing way. The TH900 is an example of headphones that get the overt coloration thing right. However they're still clean-sounding and restrained in key respects. I don't think coloration should mean "anything goes" because we "all hear differently." One of the working theses a lot of pirates I respect hold is that really, when it comes down to it, we don't all hear that differently. Sure there may be people who are more tolerant to treble razors than others, and even some people who like them, but it seems like many folks inherently dislike having sharp pain in their ears. Go figure.

I think there's too much emphasis often times on hearing differently. Instead, I think the real exciting phenomena is that we hear so much alike. However people on forums often resort to the "hearing differently" qualifier because they feel some need to try and do damage control when people don't have similar tastes. People feel threatened by others dissing their favorite headphones. I've posted a lot about my own personal philosophy with regard to audiophilia and head-fi and how it's more about fulfilling personal needs for identification and justification than headphones often times, so I'll spare everyone and refrain from rehashing all that (this is already too TL;DR as it is). Suffice to say, people like to play up "the journey" because it gives them a sense of purpose and identity in the forum's social microcosm. Desire is only potent insofar as it remains unsatisfied, and the "it" people search for is always really already unobtainable, which is what sustains the cycle of never-ending consumerism on hobbyist forums like head-fi.

I think there's value there provided one learns along the way. Also the social facet of head-fi is something I personally value. In a way, it's rather poetic to think that headphones and IEMs---a wholly solitary means of listening---can foster social interaction in this day and age, in the form of local meets and lasting friendships. Beyond the need for validation, there's a genuine desire to connect to people in sharing impressions I think. It speaks to that universal desire to extend beyond one's interiority and make contact with the outside world, to escape alienating solipsism, which is all too prevalent today. When people aren't able to convey what they hear to others, it becomes a source of much frustration. I think that's the source of a lot of forum drama: we're using a rather clunky and inadequate method---words---to describe how something sounds, using precise technical terms to describe our imprecise emotions and passions.