First off, I should mention that the name is a bit of a misnomer. There are really two layers, the titular simple FM layer, and a subtractive synth layer. Simple FM Synth is nothing fancy, but I think it sounds pretty good, for what it is. This patch started off as a basic sound source to enable me to work on the Gyre program that I use with my Buchla 200e, when I was not near my Buchla.

There are two main patches of interest, Simple_FM_Synth.maxpat, and Simple_FM_Synth_Test.maxpat. Simple_FM_Synth is what you'll use in your patches, and Simple_FM_Synth_Test is an example of ways to use it. Simple_FM_Synth_Test has a simple note generator that plays randomish notes so that you can start it playing, and then mess with the parameters of Simple_FM_Synth itself.

The FM section is a simple two-operator stack, nothing fancy here. There are a couple redundant ways to set the relationship of the FM carrier and FM modulator.

The Subtractive section consists of two oscillators, one square/pw, and one sawtooth, mixed into a filter. Even though the poly~ patch "FMSynthVox.maxpat", as delivered, uses svf~, the presets were written using 2up_svf~ instead. 2up_svf~ sounds better than the stock svf~, in my opinion, but it is only available for the Mac, so I used the stock object for this distribution. The presets are somewhat different sounding with the stock svf~. If you are on a Mac, I highly recommend grabbing 2up_svf~ from here, and editing FMSynthVox to use it.