If you hear a difference then you hear a difference though some will argue with you and tell you you didn't. I for one am glad you post your findings Craig.
 
Interesting gswits , could that be the filter in your ADAC , or moreover the noise shaping? 
 
If it is the mic it has quiet a roll off up there.
 

FYI regarding ultrasonics, it's a myth that mics and speakers cannot respond to frequencies higher than 20kHz; plenty can. That's just where the specs usually drop off. For example ADAM A7 speakers can do 35kHz at -3dB. I don't know where a -6dB point would be but it would of course be higher than 35kHz. Also there are plenty of preamps that are flat to 60kHz; analog tape recorders could often record up to 24-28kHz when tweaked.
 
However, if it is shown eventually that ultrasonic content is important to the listening experience, then I think speakers would have a woofer, tweeter, and an ultrasonic transducer like the Senscomp, which is about +/-8dB from 50 to 100kHz (either as a microphone or speaker).

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mike_mccue
If people want to remain open to the idea that stuff other than our ears can sense the higher frequencies... heck yeah I'm all for that. If we are going to go down that road it might be nice to studiously avoid talking about headphones and binaural playback. :-)

As mentioned, there's quite a bit of research regarding perception of ultrasonic frequencies although the exact mechanism remains unclear.
 
I'm keeping an open mind about this and how it affects perception of music. I can't help but remember that although the Wright Brothers flew in 1903, one of the (very) few mainstream scientists who accepted they actually flew was Alexander Graham Bell. The newspapers of that time mostly ignored the Wrights' claims, choosing instead to print articles by experts and engineers about how flight was impossible. It wasn't until Scientific American editorialized in 1906 that they thought the Wright Brothers actually flew that people started to take the idea of flight seriously, and it was finally accepted in 1908 when a Canadian (whose name I can't recall) did public demonstrations of flying.
 
There's so much we don't know. Certainty can be a setback to progress.
 

If it turns out there is actually credible evidence that ultrasonics can indeed be sensed somehow, if not by the ear and not consciously (if it was, how come no one has proved it 1000 times over with simple double blind testing?), I look forward to the discussions that follow.
 
Like whether one should use the conventional mic that "sounds better" but rolls off at higher frequencies or the one that specifically has better ultrasonic response and hence might capture stuff that - even if we can't consciously perceive it - makes whatever we're recording "subconsciously more enjoyable".  Fun, fun, fun. 

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Anderton
But the study of greatest interest to me involved measuring EEGs of subjects listening to sounds in the range of 20-20kHz, 20kHz-100kHz, and both together.
 
If they listened only to the ultrasonic sound or to no sound, certain areas of the brain didn't respond. If they listened to sounds in the "audible" range, those parts of the brain responded as expected to the stimuli. However, the activity within that same part of the brain increased significantly when the ultrasonic frequencies were also reproduced along with the usual audible frequency range.
 
Furthermore, for whatever reason there was a lag time of about 30 seconds before the increased brainwave activity occurred in the presence of the higher frequencies, and another 30 seconds before the activity ceased once the higher frequencies were filtered out. Depending on why this happens, it would imply that switching back and forth between standard audio and audio containing ultrasonics for AB comparisons would need to take this lag into account.

 
This sounds like the much discussed Oohashi paper of 2000. 
http://jn.physiology.org/content/83/6/3548
 
You can read 14 years worth of heated discussion from the "true believers", skeptics and disbelievers regarding it, but you probably aren't going to add anything to those discussions until someone can independently verify it. 

Funny, I was just on Bali for nearly three weeks. Can't say I noticed any increased brain activity - quite the opposite! :)

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