// One way of thinking about FM synthesis is to see it as vibrato. // You make a pitch, then vary it up and down at some rate. // You can change the speed of the pitch variation (modulation frequency), and also the amount of variation (modulation index). // In FM, usually only one of the waveforms - the carrier that provides the initial pitch - is sent to the output. // The frequency of the the carrier wave is continually adjusted at a rate equal to the frequency of the second wave (the modulator). // So at any given point in time, the frequency of the carrier can increase by an amount equal to the current amp of the modulator. // This has some interesting effects. #include "maximilian.h" maxiOsc mySine,myOtherSine;//Two oscillators void setup() {//some inits //nothing to go here this time } void play(double *output) { // In this example, the 'myOtherSine.sinewave' is at an amplitude of 1, it's original amplitude. // This is pretty simple and not too useful. //output[0]=mySine.sinewave(440*myOtherSine.sinewave(1)); // Perhaps you should comment out the above line and uncomment the below one instead // It shows how the frequency of the carrier is altered by ADDING a second waveform to its frequency value. // The carrier frequency is 440, and the modulation frequency is 1. // It also shows how the modulation index works. In this case the modulation index is 100 // Try adjusting the modolation index. Also, try altering the modulation frequency. output[0]=mySine.sinewave(440+(myOtherSine.sinewave(1)*100)); } // In complex FM systems you can have lots of modulators stacked together in interesting ways, and theoretically this can make any sound. // John Chowning is the guy you probably want to talk to about that. output[1]=output[0];