STT-1
PARAMETRIC EQUALIZER SECTION
(9) BAND IN/OUT SWITCH "IN"
Pushbutton switch which places its associated EQ band in circuit or out of circuit. There are
four bands of equalization on the STT-1 Origin. The four frequency bands are labeled LF (low
frequencies), LM (low-mid frequencies [20 Hz - 2.5 kHz]), HM (high-mid frequencies [250 Hz
- 25 kHz]), and HF (high frequencies). An EQ band is in circuit when its associated band switch
is depressed and LED is illuminated. Because of the equalizer's unique network-shunt design,
EQ bands should have no detectable sonic signature when they are in circuit as long as the
boost/cut control is set at zero. Band In/Out switches are provided both for comparing a single
EQ band setting versus flat-band response, and for bypassing the EQ entirely.
(10) FREQUENCY SELECT SWITCH
Rotary switch (Grayhill, gold contacts, military spec) which selects fixed high and low band fre-
quencies. LF control center frequencies are set to 20, 34, 56, 100, 180, and 270 Hz. HF control
center frequencies are set to 4.8k, 5.8k, 8.0k, 10k, 16k, and 21 kHz.
(11) PEAK/SHELF SELECT SWITCH
Pushbutton switch which selects LF band and HF band curve shape. When switch is depressed
and LED is illuminated, EQ is shelving at 6 dB per octave. When switch is not depressed, EQ is
peaking with a fixed "Q" of 1.0.
(12) BOOST/CUT CONTROL
Conductive plastic rotary potentiometer offering up to +15 dB of boost and -15 dB of cut.
Boost/Cut potentiometer has 21 detented positions for accurate repeatability and session log-
ging.
(13) PARAMETRIC FREQUENCY CONTROL
Conductive plastic rotary potentiometers (2) which sweep all center frequencies from 20 Hz to
25 kHz. The low-mid band ("LM") sweeps 20 Hz to 220 Hz
-or-
200 Hz to 2.2 kHz, depend-
ing on the status of Frequency Range Switch (below). The high-mid band sweeps 250 Hz to 2.5
kHz
-or-
2.5 kHz to 25 kHz, depending on the status of Frequency Range Switch (below). This
control is optionally available with 21-step detents for accurate repeatability and logging.
(14) PARAMETRIC FREQUENCY RANGE SELECT SWITCH "10X"
Pushbutton switch which selects 1X or 10X parametric frequency range. When switch is de-
pressed and corresponding LED is illuminated, frequencies as shown on front panel legend are
multiplied by 10X. When switch is not depressed and LED is not illuminated, frequencies are as
shown on front panel legend.
(15) PARAMETRIC
QUALITY
CONTROL "Q"
Conductive plastic rotary potentiometer which sweeps "Q" (Quality factor) from 0.4 to 4.0.
"Q" is defined as the ratio of the center frequency to the bandwidth. For example, a filter boost
setting with "3 dB down points" near 100 Hz and 1000 Hz exhibits a "Q" of approximately 0.4.
This control is optionally available with 21-step detents for accurate repeatability and session
logging.
