10.6

217Logic Pro Instruments
• A ring modulator, which is fed by the output of oscillator1 and a square wave from
oscillator2
• Colored noise for oscillator3. See Use the Logic Pro ES2 noise generator.
Oscillator synchronization and ring modulation allow for the creation of very complex and
flexible harmonic spectra. The principles behind oscillator synchronization are described in
SynchronizeLogic Pro ES2oscillators. Ring modulation principles are described in Use ring
modulation in Logic Pro ES2.
Use pulse width modulation in Logic Pro ES2
You can alter the tonal color of rectangular waveforms by scaling the width of waveform
pulses to any value. This is known as pulse width modulation.
ES2 pulse width modulation features are extensive. For example, if rectangular waves are
chosen for all oscillators, you can simultaneously modulate the pulse width of oscillator1
and the synchronized pulse waves of oscillator2 (or the square wave of the oscillator2
ring modulator) and oscillator3.
Set a basic pulse width in oscillator2 or 3
• In Logic Pro, drag the waveform rotary control that surrounds the Wave knob (see the
highlighted area in the image above).
Only oscillators2 and 3 allow you to define a base (default) pulse width, prior to any
pulse width modulation.
Set up a pulse width modulation (of oscillator1) in the router
1. In Logic Pro, choose a rectangle wave for oscillator 1.
2. In the router, choose Osc1Wave as the target, and LFO1 as the source.
3. Adjust the modulation amount slider (try a value of 0.12).
4. Choose a sine wave for LFO1.
5. Adjust the LFO1 Rate (around 0.160Hz for a slow sweep).
Use frequency modulation in Logic Pro ES2
The principle of frequency modulation (FM) synthesis was developed in the late 1960s and
early 1970s by John Chowning. It was popularized by the Yamaha DXsynthesizers in the
1980s. Although the ES2 can’t be compared with the DXseries in the discipline of pure
FMsynthesis, it can achieve some of the signature sounds of these instruments.