Studio Electronics Boomstar - Manual (Page 18)

14 Studio Electronics Boomstar Quick Start Manual Panels
5.2.5 VCO 2 - Voltage Controlled Oscillator 2
The TRACK switch selects Oscillator 2’s pitch tracking response. The ON position is the “business as usual,” 1 volt per
octave default setting. The OFF position disconnects the pitch control of the keyboard so a fixed or static pitch can be
achieved, which is useful and expressive in a variety of ways, i.e., as a fixed value low frequency modulator when the
LO setting is employed, a “flanged,” “phasey” synced Oscillator timbre effect, or a non-tracking, static drone. Come up
with some of your own!
OSC 2’s RANGE switch functions identically to OSC 1’s RANGE switch for selecting the octave: LO (low frequency
inaudible clicks), 32’, 16’, 8’, 4’, 2’.
The WAVE switch selects the Sawtooth, Triangle, or fixed Square wave.
The coarse/fine TUNE knob sets the pitch, or synced harmonic value when the SYNC switch of Oscillator 1 is in the ON
position—a very potent tweaking hot spot! The range of the tune pot is increased when TRACK is off.
The MOD DEPTH knob sets the depth at which ENV 1, or ENV 2 modulates the frequency or pitch of 2.
5.2.6 VCF 2 - Voltage Controlled Filter
A
word about the Filter:
The Boomstar’s unique, classic filter designs feature wide range
lowpass filters, and in the case of the 5089, 4075, and 3003 self-
oscillating filters. The SEM features a notch that sweeps from
low-pass to high-pass, as well as a band-pass mode. The SE80 is a
multimode filter, with dual frequency and resonance controls, for the low-pass and high-pass response. The Filter
attenuates, or cuts off the higher frequency components—those which lie above the adjustable cutoff frequency—
and passes the lower frequency components of the audio signal. [see Filter Talk, p. 25]
The FREQUENCY knob sets this cutoff frequency: the lower the cutoff frequency, the less harmonic content the
waveform will retain after passing through the filter. A wave shape rounding and smoothing occurs as this cutoff
frequency is reduced.
The TRACK switch selects the filter tracking (sometimes called keyboard follow or keyboard scaling) to FULL ,
OFF , or
HALF . Filter tracking applies keyboard control voltage to the filter: more tracking, more brightness as you ascend the
keyboard. A FULL, tracking selection makes the low end and bassy and round, and the high end cut better with its
increased brightness, clarity, and edge.
The RESONANCE knob sets the filter resonance. The resonance, or “Q,” emphasizes, or boosts, the cutoff frequency
region making the presence of harmonics more apparent. The 5089 and 4075 filters will begin to self-oscillate as
the knob passes the 3 o’clock position. Resonance is a pure sine wave and can be used as a separate tone source.
Resonance is in fact negative feedback—a signature sound of subtractive synthesis.