Nice explanation - thank you. I've got another question for you. Ring modulation (RM) creates new frequencies, called sidebands, by adding and subtracting the two original frequencies. These often sound quite cool, except the new frequencies generated a) are often not part of the harmonic series, and thus sound not in scale, and b) because of the simple arithmetic nature of how the new tones are created (simple addition and subtraction) those new tones almost never track musically across the keyboard. This is opposed to to FM/PM, which is generated by sounds that are harmonically proportionate to one another, thus giving sounds that (usually) track nicely across the keyboard. Why does FM/PM have this nice melodic property and not RM?