10.6

Table Of Contents
707Logic Pro Instruments
Signal-generating and processing components
Oscillators: Generate the basic signal. This is usually a waveform that is rich in
harmonics. See Oscillators. Many synthesizers provide more than one oscillator, and
almost all synthesizer oscillators can generate several waveform types.
Filter section: Used to alter the basic signal by filtering out (removing) portions of the
frequency spectrum. Many synthesizers have a single filter that is applied universally to
all oscillator signals. Multioscillator synthesizers can provide multiple filters, allowing
each oscillator signal to be filtered in a different way. See Filters overview.
Amplifier section: Used to control the level of the signal over time. The amplifier has a
module known as an envelope, which is divided into several elements that provide level
control for the beginning, middle, and end portions of your sound. Simple synthesizers
generally have a single envelope, which is used to control the oscillator (and filter)
over time. More complex synthesizers can provide multiple envelopes. See Amplifier
envelope overview.
Modulation and control components
Modulators: Used to modulate the signal-generating and processing components.
Modulations can be machine-based—automatically generated by a synthesizer
component—or can be manually activated by using the modulation wheel, for example.
Most synthesizers have a component called an LFO (low frequency oscillator) to provide
a waveform that modulates the signal. See Modulation overview.
Global controls: Set the overall characteristics of your synthesizer sound, such as
tuning, glides between notes, pitch bends, and monophonic or polyphonic playback.
See Global controls.
Oscillators
The audio signal of a synthesizer is generated by the oscillator. You can choose from a
selection of waveforms that contain various types and amounts of harmonics. The level
relationships between the fundamental tone and the harmonics of the chosen waveform are
responsible for the basic sound color or timbre.
Waveform types
Sine wave: Clean and clear-sounding, a sine wave contains only the first harmonic; in
other words, it is the fundamental tone. The sine wave, used alone, can create “pure”
sounds like whistles, the sound of wet fingers on the rim of a glass, tuning forks, and so
on.