This Module is currently available.
Voltage Controlled High Pass Filter
FUNCTION DESCRIPTION
The SW904B Voltage Controlled High Pass Filter attenuates input signal frequencies below its nominal cutoff setting. The attenuation below FCV cutoff setting is 24 db/oct. As the fundament is generally the loudest frequency component of a complex tone, deletion of the lowest frequency range can radically alter the timbre. The FCV cutoff point is raised or lowered in octave per volt control inputs. The Frequency Range switch sets the overall range of frequencies covered by the Fixed Control Voltage potentiometer. The Low range encompasses 4 Hz to 20 kHz, while the High range shifts 1,5 octaves up to 10 Hz through 50 kHz.
This Module is based on the original design from 1966
MUSICAL APPLICATION
The Voltage Controlled High Pass Filter is most useful for altering the timbre of input signals by deleting the predominance of the fundament partial in a complex tone. Voltage control of this module often creates a spectral sweep radically different from those associated with acoustic instruments. A thin or “tinny” sound often results when using this filter. Low frequency control voltages (10 – 20 Hz) can, if their gain is boosted from the nominal fixed level output of the 901 Oscillator, effect in a rattling or “scraping” sound (almost regardless of input signal). Connected to the Low Pass Filter in parallel, series, the High Pass Filter helps form band pass and band reject filters
