Understanding How To Use The Ratios In FM8

In this tutorial, learn how to use the ratios in FM8 from a more musical perspective. This will be helpful for all of us who aren’t mathematically inclined!

The ratios in FM8 can be difficult to grasp, especially if you don’t like thinking of ratios and math while producing. I know I don’t. I personally like to think of a number value that will tune my operator waveform to a value I’m familiar with. FM8 wasn’t my first synth and for anyone else like me who learned on synths like Massive and Sylenth1, I hope you’ll find this tutorial useful.

I initially had a hard time using the ratios in FM8 when I first started using the synth. In Massive, for instance, if I want a low saw wave  I load up a saw waveform and tune it to -12 or -24. Those numbers don’t even exist in FM8’s operators. Even though the ratios now make sense to me, I still think of them in this way. I have seen a lot of questions come through when I have made tutorials on how to make a sound(s) asking how I knew what ratio value would do what and this tutorial will teach a little bit about that.

The first important ratio to remember  is 0.5. That’s the lowest number you can have in an operator that will be in concert tuning. Meaning if you play a C note, you’re actually playing a C note. Think of that as -12 or -24 in Massive (depending on the waveform).

The second number to remember is 1.0. That is an octave above 0.5. So if you play a C1 while having the ratio of 0.5 and then turn up the ratio to 1.0, and then play C1 again, you are now playing a C2.

Here is where it gets a little confusing. 1-.5=0.5. With that logic, wouldn’t tuning an operator to a ratio of 1.5 be two octaves above 0.5? Well I did say the ratios in FM8 are confusing didn’t I? If your starting point was 0.5 (which is in tune with concert tuning) and you pitch that up to 1.5, you are not playing two octaves above your 0.5 note, you will be playing 1 octave and 7 half steps above your starting note. 7 half steps is also a 5th.

That becomes helpful to know if you want to create a two operator sound that sounds like a 5th for a chord. If you have one operator tuned at 0.5 and tune the other operator to 1.5 your sound will have a 5th in it. This would be like tuning one oscillator in Massive to 0.00 and another oscillator to 5.0

Stay tuned for next week to dive in a little further into the ratios in FM8.

Cheers,

Echo Sound Works