Originally Posted by Zanth
Right, but anyone who believes that "hearing" sound is ultimately about the vibration of some molecules is horribly mistaken. HOW the signal stimulates the brain is all fine and dandy, quite well understood yes, sure, but HOW a person hears, their perception of sound (since the ear is pretty well HARD WIRED to the brain) is the most important point of this discussion. The brain is the least understood "machine" in the universe. It is also the most complex. How each person "hears" is a result of how they "perceive" sound and music etc. Teaching people how to listen to music for instance is possible because of the brain, not because of the ear. It's not as if the sensory cells of those that have "learned" to listen have multiplied in extreme numbers, no, it is because the neural pathways of the brain have been re(constructed) in such a way as to perceive details, nuances etc, that others whose pathways are not as connected, merely miss out on. What constitutes such learning and how it can be strengthened is not very well understood. Read This is your brain on music
It should be required reading for anyone in this hobby.
The real problem with all of this talk about hearing and perception is that these neural centers that are doing the perceiving are being fed information by a mechanical apparatus that is in many ways flawed, clunky, and inefficient. The brain may perceive the sound, but the ear, eardrum, middle ear bones, and cochlea are what actually pick up the information and transform it into a form the brain is capable of understanding.
Now, knowing this, we know that the auditory cortex is effectively limited in its capabilities by equipment far upstream in the chain. (Now doesn't that sound familiar!
) We know through rigorous testing and experimentation the limits of our ability to hear certain frequencies, what our SPL thresholds are, among other things.
The point I am trying to make is that you cannot perceive something which your sensory apparatus cannot pick up in the first place. That is why there are prescribed levels for things like TMD, IMD, and noise floors, because we know that at or below those levels the effect will be literally inaudible, and we design our equipment with this in mind.
Cannot perceive something which your sensory apparatus cannot pick up... unless... your belief in the perception is so strong, that you create it for yourself.
|The problem is that one thinks! their testing equipment is good enough when in fact, it fails miserably.
Could you explain to my how our testing equipment fails? Our best equipment is many times more sensitive than our own ears and can "hear" sounds and frequencies that are far, far beyond the threshold of audibility for humans, which is why we can use it to establish standards and to determine whether or not a particular product (such as an amplifier) will have audible problems or not. For example, HeadRoom's dummy head could easily tell the difference between a headphone that had 0.05% THD and 0.04% THD, and the experiment could be repeated reliably with the same results. However, no human could ever make that distinction, even if they knew what to listen for. And that dummy head isn't even that advanced compared to something like a KEMAR manikin. We have microphones that can pick up sounds in excess of 100kHz, which puts our paltry 20kHz limit to shame. The auditory threshold at 2kHz is 2×10−5 Pa, but microphones exist that can pick up sounds much, much softer than this.
And you say our equipment fails miserably! If anything, We fail in comparison to the equipment we have designed.