I'm kind of two minds abut whether we should differentiate between hearing situations and how they're affected by outside factors... and where we draw that line.
And I agree that there's also a major grey area between "placebo" and "real influences".... and I'm not sure where to put that line either.
On the one hand, we have things like trans-cranial stimulation.
In the paper I linked to they were talking about using TCS as a sort of treatment for medical conditions.
However, is it reasonable to discount the effect the loud music at a concert has on us via other methods than our ears?
What if the audible music we listen to
SOUNDS DIFFERENT to us because that TCS has altered how our brain interprets it?
You also bring up an interesting question about the placebo effect.
For example, we know that certain chemicals, like the caffeine in coffee, actually affect how our nerves work.
Therefore, it's quite possible that your hearing acuity will actually measure differently after two or three cups of coffee, or at a different time of day, or even in a brightly lit room.
But what if your hearing acuity changes when you drink something that you BELIEVE has caffeine in it - but really doesn't?
Several studies I've read (I forget if that includes any I linked to) have noted that it is now widely accepted that there are feedback paths going from our brain to our ears.
In other words, what you're thinking CAN produce physical changes in your hearing acuity.
Your brain sends messages to your ears that alter their response characteristics.
So, in fact, it may be possible that you actually are PHYSICALLY more able to hear sounds when you concentrate on them.
Or, perhaps, it's the opposite, and your brain dials down the sensitivity of your ears when there is too much other information being processed.
(To take an extreme: What if excessive THD starts to sound good when the strobes get bright enough? )
Note that none of this specifically has anything to do with ultrasonic sounds.
Except that it opens up the possibility that, for example, an ultrasonic sound you can't hear might alter your ear's programming, which might in turn affect other things.
(What if the vocalist "sounds different" because that ultrasonic harmonic from some instrument has reprogrammed your auditory cortex... or even the nerves in your ears?)
(Or, as a few people have suggested, what if the "audible range" of that instrument sounds different when accompanied by the ultrasonic harmonics because they affect your brain?)
I'm going to suggest an interesting POSSIBILITY here..... (I'm not claiming that it's necessarily true - but maybe we should check into it).
What if the reason that, for most people, "home listening can never duplicate the experience of a real concert" is due to those extraneous factors.....
What if, at the actual concert, our brains and auditory cortex were "configured a certain way" - thanks to those bright lights, our expectations, and even a little TCS....
And we're never going to be able to properly replicate the
auditory experience unless we replicate all the other factors that account for the configuration that goes with it?....
To me, this is stuff we should be testing....
your examples are about interpretation, and the ultrasonic link seems to not even be concerned about hearing at all. yes I present hearing as a sort of spectrum analyzer, or maybe more as a sort of really weird microphone. not because I believe that our brain can't do amazing stuff with the data from that sensor, but because if something can be masked or is simply outside the range of sensitivity of that sensor, then there will be no extra data to interpret. which seems pretty important to me when considering what might matter.
now if you want to use transcranial stimulation as an argument that ultrasounds even when not perceived by our auditory system can still affect our experience, I'm fine with that of course. but I'm not fine with considering that as hearing. and if like
@Phronesis you wish to extend the notion of hearing beyond signals captured by our ears, and go deep inside the brain at a cellular level or just as a thought, I'm also fine with that but only so long as your notion of hearing is very clearly and strictly defined. because as of right not it isn't my definition of hearing. there are many non audio aspects that can trigger a change or even cause a reaction in the auditory cortex or anywhere else. just with the research available, we cannot doubt that to be true. but is it hearing? in a brain where our different senses are never strictly isolated(at least not when it comes to interpretation), one could argue that placebo is hearing. that touching is hearing. we even have people for whom the link between senses is more direct, and a sound will have a color or vice versa. but should we define human hearing with such standards?
when we agree in this section that all those non audio variables need to be eliminated in a listening test, we do imply that they all have the potential to affect our interpretation of sound. so all in all it's not a big move to go from our usual position to a position redefining hearing as a more global experience. but it's a very massive difference in definition!
even then, all we do is allow more variables to count as audio. even with that trick, demonstrating that the typical amount of ultrasounds in records is having a clear impact(a positive one!) on the listener, is still something I'm waiting to see. if anything I'd argue that if we open our definition of hearing to a wider range or variables, it automatically makes ultrasounds an even smaller part of what forms our audio experience.
