The idea of tonic is very abstract; yet it is a predestined experience for all of us here on planet Earth.
This is how the physics of sound are manifest to us through the organization of standing waves and pitch.
The standing wave’s frequency (the pitch we hear) measured in hertz, is the fundamental pitch of the harmonic series.
When you hear one note, what you are feeling is a magnitude of frequencies all vibrating, simultaneously organized, within the standing wave.
This acoustic phenomenon is known as the harmonic series. The harmonic series is derived from sympathetically organized vibrations within one single standing wave frequency. These sympathetic vibrations can be expressed as a series of mathematical ratios in reference to the fundamental frequency or sounding pitch.
Within this fundamental pitch we have the blueprint for tonality. In short we could understand every fundamental pitch as a tonal center itself, by virtue of the reacuring mathematical sequences expressed within the ratios of the harmonic series.
That is to say each pitch, as a fundamental, has the potentiality to be or become tonic with reference to its natural acoustic structure resonating the harmonic series.
– JC Heisler