![](https://help.apple.com/assets/61969817CE76B47A346B2B67/6196981BCE76B47A346B2B86/en_US/958a919fd7f4db100ada4ae333e24177.png)
EVOC 20 TrackOscillator oscillator controls in Logic Pro
The tracking oscillator follows the pitch of incoming monophonic audio signals and mirrors these pitches with a synthesized sound. The FM tone generator for the tracking oscillator consists of two oscillators, each of which generates a sine wave. The frequency of Oscillator 1, the carrier, is modulated by Oscillator 2, the modulator, which deforms the sine wave of Oscillator 1. This results in a waveform with rich harmonic content.
Important: The parameters discussed in this section are available only if the Synthesis In menu is set to Osc. See Synthesis In controls.
![Figure. Basic Tracking Oscillator parameters.](https://help.apple.com/assets/61969817CE76B47A346B2B67/6196981BCE76B47A346B2B86/en_US/3848cbcbca2fe5651e017d3038ac2809.png)
Tracking oscillator parameters
FM Ratio field: Set the ratio between Oscillators 1 and 2, which defines the basic character of the sound. Even-numbered values or their multiples produce harmonic sounds, whereas odd-numbered values or their multiples produce inharmonic, metallic sounds.
An FM Ratio of 1.000 produces results resembling a sawtooth waveform.
An FM Ratio of 2.000 produces results resembling a square wave with a pulse width of 50%.
An FM Ratio of 3.000 produces results resembling a square wave with a pulse width of 33%.
FM Int knob: Determine the intensity of modulation. Higher values result in a more complex waveform with more overtones.
At a value of 0, the FM tone generator is disabled and a sawtooth wave is generated.
At values above 0, the FM tone generator is activated. Higher values result in a more complex and brighter sound.
Coarse Tune field: Set the pitch offset of the oscillator in semitones.
Fine Tune field: Adjust the tuning in hertz.
Download the guides:
Logic Pro User Guide: Apple Books | PDF
Logic Pro Instruments: Apple Books | PDF
Logic Pro Effects: Apple Books | PDF