9

The most obvious global control is the Level control, which sets the overall loudness of
your sound. For more information about the Level control, see Envelopes in the Amplifier
Section.
Other key global controls include the following:
• Glide (sometimes called Portamento): Used to set the amount of time that it takes for
one note pitch to slide up or down to another note pitch. This control is useful for
emulating wind instruments that slide from note to note, rather than move directly to
another clear and distinct pitch.
• Bender/Bend Range: This control is generally hard-wired to a Pitch Bend wheel on a
keyboard. As the name suggests, moving the wheel up or down from its centered
position bends the pitch (the oscillator frequency) up or down. The Bender/Bend Range
parameter usually has an upper and lower limit of one octave but is typically set to
around three semitones up or down. This setting is ideal for emulating small (or extreme)
pitch fluctuations that occur in some instruments—such as when moving between
notes with a trumpet, or bending the strings during a scorching guitar solo.
• Voices: Synthesizers have a limit to the number of notes that can be produced
simultaneously. Producing notes simultaneously is known as the polyphony (literally,
this means “many voices”) of the instrument. The Voices parameter sets an upper limit
to the number of notes that can be played at a given time.
• Unison: Used to “stack” voices—with the unison voice being heard one octave above
the frequency of the played note. Because two voices are being used when you play
a note, unison has two effects—it makes the sound richer and fuller, and it halves the
polyphony.
• Trigger Mode: Trigger mode determines how the polyphony of the instrument is handled
when the number of notes played exceeds the number of available voices. Trigger
Mode also allows you to assign legato mode. Essentially, this control changes the way
the synthesizer responds to your playing technique and is invaluable when you are
emulating monophonic instruments, such as flutes, clarinets, and trumpets. When you
use the Trigger Mode control, if you assign a last note priority, a playing note will be
cut off by playing another note.
• Last note priority: When new notes are triggered while all voices are playing, the
synthesizer frees up polyphony (voices) by ending the notes played earliest. This is
the default trigger mode of Logic Express synthesizers when in a monophonic mode.
• First note priority: Notes played earlier are not stopped. In this mode you need to
stop playing notes in order to play a new one after you have reached the limit of the
polyphony (voices) of the instrument.
Note: The Trigger Mode parameter can also allow you to set priorities for lower- or
higher-pitched notes when playing monophonically (one voice at a time) in some
synthesizer designs.
366 Appendix Synthesizer Basics