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Table Of Contents
In a synthesizer, this type of modulation takes place in the audio spectrum. Depending
on the design of the instrument, you can hear the signals of either the carrier alone, being
modulated by the modulator, or both oscillators. The interaction between the two
oscillators alters the waveform signal of the carrier and introduces a number of new
harmonics. This harmonic spectra can then be used as the source signal for further sound
processing, such as filtering, envelope control, and so on. For further information, see
Frequency Modulation (FM) Synthesis and EFM1.
Frequency Modulation in Ultrabeat
In FM mode, Oscillator 1 (the carrier) generates a sine wave. Its frequency is modulated
by the waveform of Oscillator 2 (the modulator).
When Oscillator 2 outputs a positive (or higher) frequency signal, the frequency of
Oscillator 1 increases.
When Oscillator 2 outputs a negative (or lower) frequency signal, the frequency of
Oscillator 1 decreases.
The net effect of speeding up or slowing down the frequency of Oscillator 1 in each
waveform cycle is a distortion of the basic wave shape. This waveform distortion also has
the side benefit of introducing a number of new, audible, harmonics.
The more complex the Oscillator 2 waveform, the more partials will be created by
increasing the FM Amount during the FM process. Keep an eye on the display to see how
the sine wave takes on an increasingly complex shape.
Note: Oscillator 2 must be enabled if you want to use frequency modulation.
Important: The impact of any frequency modulations you may perform depends onboth
the frequency ratio and the modulation intensity of the two oscillators.
To set the frequency ratio and adjust the modulation intensity
1 Adjust the Pitch parameter values of one, or both, oscillators.
2 Adjust the amount (intensity) of frequency modulation with the FM Amount knob.
FM Amount knob
This parameter can be modulated by the sources found in the “mod” and “via menus.
For more information, see Working with Modulation in Ultrabeat.
258 Chapter 11 Ultrabeat