E-Mu Ultraproteus Operation Manual page 89

WHAT IS A FILTER?
Most of the instruments in UltraProteus are complex waves containing many
sine waves of various amplitudes and frequencies. A filter is a device which
allows us to remove certain components of a sound depending on its fre-
quency. For example, a Low Pass Filter lets the low frequencies pass and
removes only the high frequencies.
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A filter that lets only the high frequencies pass is called a High Pass Filter.
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A filter which only lets a certain band of frequencies pass is called a Bandpass
Filter.
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Cutoff Frequency
Output of Filter
40 80 160 360 720 1440 2880
Frequency
Initial Frequency
Filter Output
40 80 160 360 720 1440 2880
Frequency
Center Frequency
Filter
Output
40 80 160 360 720 1440 2880
Frequency
Low Pass
Filter
...
High Pass
Filter
...
Band Pass
Filter
...
Chapter 7: Preset Programming
PRESET PROGRAMMING
85