2009

The Formant Filter display is divided in two by a horizontal line. The upper half applies
to the Analysis section and the lower half to the Synthesis section. Parameter changes
are instantly reflected in the Formant Filter display, providing invaluable feedback on
what is happening to the signal as it is routed through the two formant filter banks.
• High and Low Frequency parameters: Determine the lowest and highest frequencies
allowed to pass by the filter section. Frequencies that fall outside these boundaries will
be cut.
• The length of the blue bar represents the frequency range for both analysis and
synthesis—unless Formant Stretch or Formant Shift are used, as discussed in “Formant
Stretch knob” and “Formant Shift knob” below. You can move the entire frequency
range by dragging the horizontal blue bar at the top. The silver handles on either
end of the blue bar set the Low Frequency and High Frequency values, respectively.
• You can also use the numeric fields to adjust the frequency values separately.
• Lowest button: Click to determine whether the lowest filter band acts as bandpass or
highpass filter. In the Bandpass setting, the frequencies below the lowest bands and
above the highest bands are ignored. In the Highpass setting, all frequencies below
the lowest bands are filtered.
• Highest button: Click to determine whether the highest filter band acts as bandpass or
lowpass filter. In the Bandpass setting, the frequencies below the lowest bands and
above the highest bands are ignored. In the Lowpass setting, all frequencies above the
highest bands are filtered.
• Formant Stretch knob: Alters the width and distribution of all bands in the synthesis
filter bank. This can be a broader or narrower frequency range than that defined by
the blue bar (see “High and Low Frequency parameters” above).
• Formant Shift knob: Moves all bands in the synthesis filter bank up and down the
frequency spectrum.
152 Chapter 6 Filter Effects