In this tip, we’re going to take a look at two of the FM algorithms offered by Operator, and discuss the way in which they work differently and how that affects the subsequent tweaking.

I’m going to pick up where I left off in the previous tip, where oscillator A was generating the main body of a kick sound, and oscillators B and C creating the attack. (For that reason, I’m going to ignore oscillator D and trust that you can glean from context how it might contribute if used.)

One of the algorithms that jumped out at me was this one:

Picture 8

In this algorithm, only oscillator A is being sent to the output. The other three are being used as modulators (also referred to as operators). As the diagram of this algorithm shows, oscillators B and C are both simultaneously modulating oscillator A.

This means that oscillators B and C are both contributing to the attack of the sound simultaneously, and can be balanced by adjusting their volumes. For example, if I were to turn oscillator B all the way down I would still hear the modulation effect of oscillator C.

Picture 9

Bearing this in mind, you can adjust them both to tatse.

This algorithm is another story:

Picture 10

In this one, oscillator A is still the only one being sent to the output. Oscillator B is modulating A, while oscillator C is modulating B.

What this means is that the function of oscillator C is somewhat less direct than it was previously. All it does is change the character of the attack by modulating oscillator B. In this case, turning oscillator B all the way down would remove the attack sound completely because it’s the only one directly attached to A.

Therefore, if you like the timbre of the sound generated with this algorithm but the attack is too loud, all you have to do is turn down oscillator B. Once you’ve got the volume of the attack right, oscillator C can be tweaked to adjust the character.