[bigshot]

Directional cues in stereo recordings (without artificial spacial processors on playback) are all affected by frequency response, just as the sound of an acoustic guitar or violin would be. Frequencies ARE sound. You can't hear time without them.

 

[jaddie]

Quote:

Directional cues in stereo recordings (without artificial spacial processors on playback) are all affected by frequency response, just as the sound of an acoustic guitar or violin would be. Frequencies ARE sound. You can't hear time without them.

Affected by frequency response, yes, but not just frequency response.  Direction cues include HRTFs, which include inter-aural time delays, frequency response differentials, intensity vs frequency differentials...etc.  You can reposition a phantom image without altering frequency response, and you can alter frequency response without repositioning a phantom image.  You can, of course, alter both in a more or less complimentary way.  But when where talking about color and EQ, we can do that with a large degree of exclusivity to directionality so long as both channels track.
 
Not even going to address the last sentence...we'll just go in a circle.  

 

[bigshot]

The last sentence is the whole point. Nothing else matters if your sound is imbalanced. Taming the response is job one.

 

[jaddie]

Quote:

The last sentence is the whole point. Nothing else matters if your sound is imbalanced. Taming the response is job one.

We're probably really in agreement and just getting hung on details.  
 
The last sentence I was referring to, actually two sentences, "Frequencies ARE sound. You can't hear time without them."  I'm not going to address that one, as is.  You'll have to try to state it better.  From one angle, it appears there's a misunderstanding of the difference between time response and frequency response. But perhaps it's just not written well.  
 
I would agree that taming response is job one.  I don't think there's good agreement in the world of headphones as to what the target response is to be though.  I think my point about it being, at present, subjective was made earlier.  In any case, headphones are not at all "flat", and if they were they wouldn't sound right.  As I said, there isn't a good agreement as to what is right, though.
 
You also said, "*Everything* you hear is frequencies." then made certain incomplete assertions about directional cues.  My point is, there's much more to spacial hearing than just "frequencies".  
 
Getting back to headphones coloring sound, we both agree that neutrality is the goal, right?  Now, grab your most neutral headphones and take a look at their frequency response.  Now grab your next favorite most neutral headphones and look at their response plot.  I can promise you, they will be quite different, and I don't even have to know what your choices are.  And it's not about price either.  
 
To put the thread back on track, the OP asked if sound signature matters if you have EQ.  The answer would be yes, and the reason is you can't completely neutralize a highly colored set of headphones with EQ tuning by ear, and especially without quite a bit of experience with EQ.  At best an equalizer might make a general improvement, and is not a bad thing to do, but you're way ahead starting with neutral phones to begin with.  
 
How's that?  Work for you? 

 

[bigshot]

I think most headphones could be corrected to a reasonably flat response with EQ. If speakers can be calibrated, with much wider varience of sound, headphones can. It can't make a transducer put out a frequency it was never designed to put out, but it can fix imbalances.

 

[jaddie]

Quote:

I think most headphones could be corrected to a reasonably flat response with EQ. If speakers can be calibrated, with much wider varience of sound, headphones can. It can't make a transducer put out a frequency it was never designed to put out, but it can fix imbalances.

Totally agree.  The problem is one of practical accurate measurement.  Headphones response is affected by them sitting on, around or in the ear, and the ear itself.  Measurement heads are available, but expensive and somewhat generalized in character.  By contrast, measuring speakers in a room with a calibrated mic is fairly easy to do with the right software.  The mics that come with AVRs with auto-cal are good enough to do it, and since the response you want is the speaker and room together, that sound field is available for sampling. 
 
If there were a way to collect standardized response measurements of lots of headphones, and provide the data for download and importing into a users digital equalizer, that might be the most practical way to do this.  Guys like the folks at headphone.com, for example, have lots of data, we just have no convenient way to import it, and create the reciprocal EQ curve.  
 
Oh, and no target curves, like I said before.  The desired response won't measure flat inside a measurement head and ear. The measurements would need to be either normalized, or a target curve involved.  Then, of course it's totally possible without even inventing anything.