[buonassi]

Quote:

If I undestand correctly, headphone measurements are already compensated that way, mapped to diffuse-field responce (usually) or free-field responce(rarely). One who performed such compensation curve creation can also measure that test headphone on a flat baffle and get a transfer function which would allow other people using similarly set-up baffles to see equalised responce.
There's however a problem that there are some ear canal resonance effects which are triggered just by presence of headphones by head, they differ by person and by headphone's construction, so one wouldn't be able to see how _exactly_ headphone would produce sound for a person. A headphone that is flat by above means could have some mad spikes in FR in 6-11 kHz range.

I personally strive for a headphone with a straight-flat uncompensated responce, that is optimal for binaural reproduction, although pretty much requires use of a crossfeed at least.

I almost hate to interject being such a newbie, but I did want to share some anecdotal musings to this science thread - hope I'm not out of line.

At least for me, I've experienced ear canal resonance to the point where it almost made me wonder if I should forsake headphones for near-field monitors instead (where the FR isn't as "grainy" up top for me). I know this because I have a pair of studio monitors in an acoustically treated room with bass traps and the whole nine. Then I simply caved and decided to start EQing my cans. It's odd how even each ear responds differently to the same frequency. I have discovered that for most headphones there are almost always two peaks (5 and 7K approx) and one null (8K approx) that I have to smooth out before I can enjoy the sound - and it's not like these peaks and nulls correspond to any measurement graphs - it's gotta be my ears! I'm talking 12-18db in some cases. On the null I have to usually do a surgical Q boost around 8K for me to hear that frequency (and its close neighbors). I don't think I have hearing damage (I'm 37) and can hear up to 16.5K with ease).

So it's good to see this thread and I'd vote "yes to pinnae" for measurement best practice, though I admit this still won't work 100% as everyone's ear is different from the next person's. When you put high frequency energy into a small chamber, nasty things happen. I think we need to accept that as a limitation to headphones and praise them for the other things they do well. Ie, low FR. A good phone can balance the lows much better than a typical room setup with speakers due to room acoustics. Then again, the speakers can do a better job at the highs even after considering HRTF. At least subjectively with my experiences.

Anyways, just a couple thoughts to add. Oh, and I too use crossfeed on headphones. I'd be happy to talk shop with anyone wanting to know more. I'm subscribing to this thread!

 

[castleofargh]

this thread isn't young, I don't know if it will come back from the dead. but the matter is brought up in pieces fairly often on other threads.
you might wish to look up the "smyth realiser" products. the latest model from a kickstarter campaign should come out this summer if all goes well. the purpose is exactly to try and get headphones to sound like speakers, and the method of calibration used, is indeed to put microphones in the ear canal to account for most of our physical individuality.

about reaching even 18db in some places for your EQ isn't that strange IMO. of course it could be some comb filter effect in the room. but even counting that out, some data from someone's HRTF can show that kind of magnitude in local frequency areas.

here is somebody with the sound source at 30° and horizontal, taken from his HRTF. but of course the response then changes for somebody else or even for that same person at a different angle.

 

[buonassi]

you might wish to look up the "smyth realiser" products. the latest model from a kickstarter campaign should come out this summer if all goes well. the purpose is exactly to try and get headphones to sound like speakers, and the method of calibration used, is indeed to put microphones in the ear canal to account for most of our physical individuality.

I sure will check this out, thanks. I've been pondering something like this in my mind, but couldn't conceive of how to do that. Mics in the ear canal, I gotta see this!

 

[buonassi]

Is it generally accepted that IEMs are better for FR accuracy for the reasons we're discussing? I'm thinking that even IEMs are a challenge because each's ear drum has learned to hear sound with respect to their outer ear anatomy. My inclination is that I may find IEMs more pleasing, but have heard some very expensive ones that sounded horrible to me. Then again, just heard the 64audio A6 at a mixing convention and really enjoyed them.

 

[castleofargh]

with headphones we bypass the head/body and get the ear or part of it, but from an angle that may be a concern if we're trying to replicate sound source at 30° like speakers. with IEMs we also bypass of the external ear so for better or for worst, there is no argument about angle of incidence on the outer ear with IEMs.
it's hard to think in term of accuracy when discussing a moving target. your neutral is probably at least a little different from my neutral. it's not as simple as speakers or real life sounds where we can go for electrically flat and expect our brain to calibrate things for our entire body.

 

[buonassi]

I found this shortly after reading your reply. It's interesting that different guys involved had resonances at slightly different frequencies though the IEM was the same. Even more interesting, is how this old school electronics engineer made his own capacitive circuits to attenuate those peaks!

http://www.linkwitzlab.com/reference_earphones.htm