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Table Of Contents
FM (Intensity) knob: Sets the amount of carrier oscillator frequency modulation by the
modulator oscillator. As you adjust the FM knob, the intensity (and number) of newly
generated overtones (harmonics) increases-making the sound brighter.
Note: Although the technology behind it is very different, you could compare the
FM (Intensity) parameter with the Filter Cutoff parameter of an analog synthesizer.
Wave knob (Modulator): Chooses a different waveform for the modulator oscillator. See
Choosing a Different EFM1 Modulator Waveform.
Fixed Carrier button (Carrier): Enable to disconnect the carrier frequency from keyboard,
pitch bend, and LFO modulations. This allows you to produce a carrier tone that is free
of these modulation sources.
Setting the EFM1 Tuning Ratio
The carrier frequency is determined by the played key, and the modulator frequency is
typically a multiple of the carrier frequency.
You can tune the modulator and carrier to any of the first 32 harmonics. The tuning
relationship (or ratio) between the two significantly changes the base sound of the EFM1,
and is best set by ear.
The Harmonic knobs are used to set the tuning ratio between the Modulator (left) and
Carrier (right) oscillators.
As a rule of thumb: even tuning ratios between the carrier and modulator tend to sound
more harmonic or musical, while odd ratios produce more inharmonic overtones—which
are great for bell and metallic sounds.
In this respect, you can view the tuning ratio as being somewhat like the waveform
selector of an analog synthesizer.
Note: The Harmonic and Fine tune knobs only affect the tuning relationship between
the Carrier and Modulator oscillators. These should not be confused with the global Tune
and Fine Tune parameters, which determine the overall tuning of the EFM1 (see Adjusting
Global EFM1 Parameters).
Some tuning ratio examples to try
µ
Set the modulator and carrier to the first harmonic (a 1:1 ratio), and the EFM1 will produce
a sawtooth-like sound.
µ
Set the modulator to the second harmonic, and the carrier to the first harmonic (a 2:1
ratio), and you will produce a tone that sounds similar to a square wave.
132 Chapter 6 EFM1