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Chapter 14 EVOC 20 PolySynth 161
Formant Filter Parameters
The Formant Filter display is divided into two sections by a horizontal line. The upper
half applies to the Analysis section and the lower half to the Synthesis section. Changes
made to the High and Low Frequency parameters, the Bands parameter, or the
Formant Stretch and Shift parameters will result in visual changes to the Formant Filter
display. This provides you with invaluable feedback on what is happening to the signal
as it is routed through the two formant filter banks.
High and Low Frequency
The blue bar shown just beneath the EVOC 20 PolySynth logo is a multi-part control
which is used to determine the lowest and highest frequencies allowed to pass by the
filter section. The length of the blue bar represents the frequency range for both
analysis and synthesis. Frequencies of any audio input which fall outside these
boundaries will be cut. All filter bands are distributed evenly across the range defined
by the High and Low Frequency values.
 To adjust the Low Frequency value, simply click-hold on the silver slider to the left of
the blue bar, and drag to the right (or left). The value range is 75 to 750 Hz.
 To adjust the High Frequency value, simply click-hold on the silver slider to the right
of the blue bar, and drag to the left (or right). The value range is 800 to 8000 Hz.
 To adjust both sliders simultaneously, click on the area between the slider halves
(directly on the blue bar) and drag to the left or right.
 You can make changes to the High and Low Frequency values directly by editing the
numerical fields below the blue bar.
Controls the lowest and
highest frequency