Not sure what title to put here, but it's an important question.

[bandcoach]

^ Again, I know about all of that stuff. I've been doing music theory before you guys could probably talk (except for maybe Bandcoach). It's not a music theory thing, it's more of a sound design thing. Like how some sounds sound dull or flat compared to other sounds which can make a beat sound boring. The problem is, I can't think of how to properly phrase the question which is why I'm getting all these answers which are actually true, but not what Im looking for.

so it is a sound design question and the focus is: why do some sounds sound dark and others sound bright and yet others are just meh....??????

this comes back to overtone content of the individual sounds and probably the harmonic/overtone/spectrum profile over time

A harmonic is a whole number multiple of the fundamental freq with its own phase and amplitude envelope - church organs or, more correctly, drawbar organs use the principle of harmonic mixing to create sounds

Dark sounds tend to have fewer overtones/harmonics and little in the way of higher freq energy - just enough to provide the colour without overshadowing the fundamental. these harmonics/overtones may also be inharmonic to the fundamental freq or just widespread skipping some intervening harmonics

bright sounds have more harmonics over a wider range with more intensity per harmonic

meh sounds just do not ignite our focus one way or the other

 

[Deezel]

^ That's exactly the answer I was looking for.

And ironically, i just figured out some of the words I was looking for are timbre and overtones and their affect on people's perception of music. I figured it had something to do with the number of harmonics, but couldn't figure out why simply raising the sound a few octaves didn't make some sounds brighter, but instead makes them sound whiny and distorted. Thanks alot man.