Music (as well as any “complex audio”) is an interesting subject to me. Take the recording of Jerusalem (And Did Those Feet, in Ancient Time) by Lesley Garrett, for instance. If you listen to the standard recording of it, you’ll hear her start to sing the first verse of the song at 1:43 (on an unrelated note, she has an absolutely beautiful voice here, I challenge any contradicting opinion). If you listen to it with the pitch a little lower (I usually have Musicolet set to p=0.85), you can hear a five-note pattern at 1:44 that is nowhere in the song, apart from that one moment. It doesn't sound bad, it sounds like an orchestra. Ms. Garrett's voice (obviously) becomes a lower pitch, somewhere around the tenor/alto range, I believe, and the five notes can be heard as if they were played in the “melody octave” (it’s what I call the range of notes that falls within singing range for me, it just helps to have that label) and they're somewhat-more pronounced. At p=0.70, the notes are pronounced, and at p=0.50, most things below that part of the staff, as well as the voice, is distorted.
Anyway, rant over.
The thing I'm bringing up here isn’t to download an app and screw with the settings to see what you can and can’t hear in your music; rather, it’s about how sound is an amazing thing when well and complex, I find music to be the best examples to use. Sound, like so many other things, is often overlooked when you’re talking about complex and delicate things. Sure, it’s just a form of non-electromagnetic waves, but at the same time, there's more to it that just that. Sound is closer to an art than most people realize (so long as it’s not irritating clatter) and, like art, can be deconstructed and analyzed from multiple viewpoints. Look up a picture of the Zaisan Memorial in Ulaanbaatar online, you’ll understand what I’m getting at. Sound, like art, can convey worlds of different meanings and messages, sometimes without even changing the most-minuscule of details.
At some point, I’d like you to take a song and run it through any full-featured audio program (Musicolet for Android & Audacity are both good options) and experiment with it by tweaking some aspects like speed and pitch in small increments. Musicolet is a music player, so it won’t mess up the original song file, but I’d recommend you use a copy of the song of your choosing if you use Audacity, that way, you won’t have to worry about anything getting overwritten that you care about. Do this and listen to how the song changes, listen to what parts become audible or more noticeable and vice-versa. It’s an amazing experience, believe me.