Frequency modulation refers to using the output of a low-frequency oscillator to continually alter (modulate) the frequency of another oscillator. This example provides the user control of the amplitude and frequency of both the "carrier" oscillator (the one we hear directly) and the "modulator" oscillator (the effect of which we hear indirectly). The output of the modulating oscillator is added to a constant (the main frequency), thus causing the carrier frequency to fluctuate up and down around that central frequency.
This patch shows three different ways to convert MIDI pitch value to frequency.
As expressed in Fechner's law, our subjective sensation of a phenomenon is often proportional to the logarithm of the empirical measurements of the intensity of the physical event that evokes that sensation. One example of that in musical contexts is that our sensation of changes in musical pitch are proportional to the logarithm of the change in the measured fundamental frequency of a tone.
This patch demonstrates the sound of linear and exponential changes in pitch and amplitude.
This patch doesn't do anything musical, but it shows the math formulae that underlie the mtof, ftom, atodb, and dbtoa objects.
The objects mtof and ftom provide easy conversion between MIDI pitch numbers and their equivalent equal-tempered frequency values.