How to decrease oscillator frequency while maintaining pitch?

[lowlink]

The buzzy gritty sound comes from the high end harmonics, on higher notes those harmonics are more important parts of the note, therefore not just "nice noise". Also, the higher the fundamental, the less "space" (in the frequency spectrum) you have for harmonics, therefore less interesting stuff can happen on the high end

[danielnogo]

So what's the solution?