We recently looked into listener preferences for different headphones equalized to different target responses. The diffuse and free-field options were indeed perceived by listeners as sounding too thin and bright. The most preferred headphone target response was based on binaural measurements of a loudspeaker calibrated in our reference listening room, which is neither diffuse nor free-field, and has a certain amount of low frequency room gain.
There appears to be a trend to reach for a more pragmatic approach to voicing headphones, Paul Barton appears to be on the same track.
Thank you for sharing your current research with the Head-Fi community. I suspect that it is the groundwork for more exciting developments we can look forward to in headphone manufacture. After all, AKG has been resting on its laurels a bit with the half-dozen versions of the K701
There's a difference between a double-blind test and an ABX test. A double-blind test is defined as a test method where neither the administrators nor the test subjects are aware of the choices or control group. The ABX test is a kind of double-blind test, but not the only kind. It may be that in this case ABX testing isn't quite what we're after anyway. An ABX test is designed to identify the presence of a difference between two samples, not to evaluate preferences.
The way I introduced the thread was unclear and my references to ABX have been a little confusing. I am indeed talking about both ABX tests to determine minor differences (different earpads, aging/burn-in, design clones, etc.) as well as double-blind testing in general where a trained listener may have become accustomed to a variety of headphone models and gained an ability to differentiate based them based on ergonomics/exteroception rather than sound alone. The sense of touch is a unique consideration when it comes to headphones, I figure that minimizing its effects might be useful in conducting comparative listening tests of headphones of different form factors.