Faster than a Speeding Bullet
That is ear-speed. Your survival depends upon it. My being is most affirmed in the shared reality of precisely that speed. Most professional musical training consists of ceding precedence of that speed to more predictable elements that can be written down: not only beats and bar-lines, but discrete pitches as well.
Had I not had occasion to sing regularly Latin hymns printed in neumes I would never have grasped the extent to which my ear had been regimented by the lines and spaces of conventional notation.
Upon first discovering Tonal Refraction I knew that I was encountering precisely that level of regimentation, both in terms of time and of tone motion. Truth is, the voice slides, more or less; the more confident the opera singer, the greater the power thereof. Truth is, too, that the beat was best described by Paul Hindemith as being rather like the pencil-drawn line on the board taken to the saw-mill: is the blade to be directed left, right, or center of the line.
I observe tempo markings often to be indications of precisely that level of metric autonomy, with some giving priority to independent movement between voices - Moderato, e.g., - and others suggesting greater vertical agreement - Allegro con brio, e.g.
This is open for discussion, especially in the light of specific works.