The people who are creating targets for 5128 are the definition of DIYers and that is precisely the problem. B&K is specifically staying out of it. It is an unfinished tool for the job at hand.
Ultimately, we are all DIYers - even Sean and Todd have some DIYish fixtures in their research
And of course this is the nature of scientific inquiry. Now, Headphones.com is not (presently) doing a very significant amount of real science - that might change in the long run, but at present the time and personnel costs of comprehensive studies have left them as a "maybe someday" thing for ex. listening tests - but there's a pretty strong appreciation of the lit there, and it's one I'm doing my best to stoke rather than quell.
If two guys can create a target for a headphone fixture in little time with so little effort, we would have to conclude that Harman and crew didn't know what they were doing! Hobby work like this hugely trivializes the research needed to find acoustic measurements that have a prayer of correlating with listening tests.
This isn't necessarily true at all! Research does not have to be completely reduplicated if you can establish that prior research is indicative - Sean didn't replicate Gaetan Lorho's listening tests, for example, but his work references off of Gaetan's.
If the above was done and hence we had a comparable solution with 5128 that we have with GRAS 45, then there would be no fragmentation. Anything else will create noise and confusion.
Given what Sean has shown regarding the differences between different fixtures (and pinnae on the same fixture, e.g. Todd's pinna vs. the KB500x used on your 45CA), fragmentation is an inevitability of a world where multiple pinnae exist.
Since multiple pinnae exist on humans, I'm hesitant to call this a problem per se, however.
It is a complete misunderstanding to think there is one preferred tilt for room response as to then try to mimic that for headphones. Every room needs to employ a target curve which fits the listener preference as driven by what they listen to. Music product has no standard. No agreed upon frequency response or tonality. No way then you can try to lock onto a preferred bass vs treble response. Hence the reason Harman curves were kind of a moving target here.
This holds for headphones and speaker-room response about equally - there's a spread of preferences between individuals and (to a smaller extent) a spread of individual preferences based on content.
@Sean Olive has strongly advocated for user adjustable tone controls on headphones for this reason, and I firmly agree - and something we'll hopefully be rolling out quite soon is visualizing preference as a "spread" rather than a single line, drawing directly on Toole and Olive's work.
You have no data to back that. The testing and comparison could very well be pointing to a design flaw in 5128. Remember, I measured nearly identical results to Dan Clark proving the repeatability and reliability of using GRAS 45. Fixture is switched by skilled operators and results were clearly odd. This should point the finger at the fixture first.
This really isn't a reasonable contention a priori. We know that the geometry of the 5128's pinnae is correct. We know that their flexibility is analogous to the KB500x pinnae. We know that its ear impedance is a better match for human listeners than the 60318-4 coupler. Why should our presumption be that a difference in response reflects a flaw on the part of the measurement system, rather than demonstrating how an acoustic source interacts with varying loads?
Not at all. There is no extensive research. And what there is, points to generally titled down response and not any specific angle. For this reason, Dr. Toole says you must have tone controls and famously coins the phrase "circle of confusion." The best paper out there was led by Dr. Sean Olive where he says this in the conclusion section:
The Subjective and Objective Evaluation of
Room Correction Products
Sean E. Olive1, John Jackson2, Allan Devantier3, David Hunt4 and Sean M. Hess
"Finally, the authors caution readers from generalizing
these test results to conditions outside the experimental
ones described here. Although the acoustical properties
of the loudspeaker and listening room in these tests
were fairly representative of typical setups in homes, the
quality of the program material will, in part, influence
how good a room correction sounds. Given that today,
the sound quality of commercial recordings remains
highly variable, there are always opportunities for good
room corrections to sound bad, and for bad room
corrections to sound good. Until the recording industry
emerges from its “circle of confusion” [1], the ideal
target curve for a room correction may be a moving
one2."
The only thing we know is that flat target sounds bright. Beyond that, the decision must be in the hands of the listener, guided by their ears.
While it's certain that there's a need for tone controls - in headphones and speakers both - it seems profoundly odd to me to characterize things this vaguely regarding preferred in-room response. Part of the Harman headphone project itself was indeed
a quantification of preferred in-room response with "good" speakers. The fact is, we prefer a *relatively* consistent across listeners slope with speakers, just as we prefer a relatively consistent across listeners response with headphones - and part of Sean's research programme was, specifically, demonstrating that we have roughly the same preferences across both...
I'd like to again invite you to discuss this in a more unified space with spoken tone audible - heck, maybe you, Sean, Andrew and I could sit down during a convention or something, and have a camera rolling?
