We are barely scraping the surface here. The point is that the inner functioning of the ear mechanism itself is vastly complex, even before the neuronic energy is sent to the brain for processing.
I was under the impression that the only part of our body that can "sense" sound is the ear drum, but then what you’re saying is that since our ear drum is only part of a complex network that forms a mechanism to "sense" sound, therefore it’s possible our brain can get sound information from other than our ear drum.
So there are three options to this argument:
1. If what you said is true, then even if our ear drum can only vibrate at 20KHz max, other parts of the ear has the possibility of vibrate at higher then 20KHz. I mean our body works like a machine in that sense. You need something to vibrate at higher than 20KHz for our brain to process signal. Otherwise where would the brain get the information from?
2. But if the ONLY part of our body can vibrate is our ear drum, then I don’t see how we can sense sound at higher than 20KHz.
3. The third argument is this. Considering the equation Y = 1/x.
Y is approaching zero but never gets to absolute zero. Y will get smaller and smaller but never zero. In general that’s the nature of our analog world. Nothing is absolute zero. So our ear drum is like that. Is possible that the ear drum does not get cut off right at 20KHz, but its response after 20KHz gets smaller and smaller but just enough to be able for the brain to obtain information. And when we say "we don’t hear it", it’s our brain that "told" us that we don’t hear it, but that does not mean our brain did not process it. Think about it. If we are constantly being interrupted by supersonic sound, we would be driven to crazy. Trust me. I know. I used to have a girl friend lols.
A lot of people say that truely low bass can only be sensed, and not heard. Our whole body can be thought of as a giant ear drum but for only very low frequency. Our body can actually vibrate but only at very low frequency. So when we "hear" low bass, I guess it’s more like the sensors in our skin telling our brain about the low bass (how else would we know if somebody punched us?). In that respect, not only our ear drum can hear low bass, our entire body can hear it too.