Really interesting.
Yes its something I come across a lot in working with sound and synthesis. The vibrato analogy is perfect. If you modulate the frequency of an oscillator playing a pure tone (sine wave) with another very slow oscillator, you will get a slow up and down motion of the frequency (weeaaoooweeaaoooweeaaoooweeaaooo).
If you beging to speed it up at some point it becomes more like a character in the sound, at which point it is like a musical vibrato. If you speed it up further, it reaches a stage when the vibration is so fast that we hear it as an extra harmonic in the sound, i.e. it adds complexity to the sound. This is known as audio-rate modulation. Its the basis for a form of synthesis called FM synthesis (FM=Frequency Modulation). Its a great way of getting harmonically rich sounds. Anyway, the point is there is a threshold where we percieve the extra harmonic on a different scale.
Its an interesting way of looking at how we percieve other dimensions of our reality... light is also a spectrum of frequencies, and i read somewhere that taste and smell are also... I guess touch also works like this, in that something bumpy, when made finer becomes like a texture where we cannot differentiate the individual bumps; it is just a continuous surface with texture.
I post a sound example I just made to illustrate
The demo is made with 3 oscillators. Starts as just 1 then, osc 2 comes in slowly and speeds up, until it becomes new harmonics in the tone. Then osc 3 starts to modulate osc 2, at the beginning audible and then as it crosses the theshold becomes a contiunous tone again, but this time more complex sounds are made (multiplying the harmonics again).
I play with frequency and depth a bit (may be too long!) and then wind it back down.
balaganist is a fictional character who loves playing the game of infinite existence. he amuses himself by posting stories about his made up life in our plane of physical reality. his origins are in other dimensions... he merely comes here to play.