Ok, so apparently nobody at AV123 is familiar with auditory physiology. It might help them to study up really quick.
The tiny bones in your ear may still vibrate, yes, but there's an organ behind these bones called the cochlea that is responsible for turning that mechanical vibration into signals that the brain understands. The cochlea is filled with fluid and is lined with thousand of tiny hairlike cilia, each of which is attached to a nerve that is connected to the part of the brain responsible for "decoding" sound.
When a sound wave hits the eadrum, it vibrates the three bones of the inner ear, which in turn cause pressure waves that travel down the spirals of the cochlea. The nature of the pressure wave, which is dependent upon the frequency of the initial sound, determines which cilia it excites. And it is an excited cilia that causes us to say "I hear something."
So guess what -- the reason a person with normal hearing cannot hear frequencies above about 20kHz isn't that the brain doesn't care to pass that information along in a recognizable fashion, it's that those frequencies don't excite any cilia and thus don't generate any brain signals whatoever.
Here's a description of the workings of the ear in more detail
So if listening to music that contains information well above the 20kHz threshhold does actually result in an "emotionally connected and involved feeling" -- it's got nothing to do with how the brain processes the sound and more to do with the psychological effect of "well, I know there's more sound playing, so it
must sound better."
Now, I'm not saying these ERTs don't do a thing. You'll notice that the two selectable crossover points of 11kHz and 15kHz still fall within the range of ordinary hearing. So any perceived benefit they deliver to your audio experience may still be real. Meaning if you took a before and after frequency response of your speakers+ERT, they'd differ.
