CAUTION:
A microphone with an unbalanced output may be damaged if connected to this input.
CAUTION:
AudioControl Industrial assumes no responsibility for microphones damaged in this
CAUTION:
manner. Connect microphones with ¼" phone plug connectors to the Balanced Input 3
CAUTION:
connector.
D
B i
nput
S
EnSitivity
The
D
B i
nput
S
EnSitivity
control and switch select the reference level of the curve shown in the display
window. The control to the right of the input selector switch is a fine adjustment and alters the range
selected by the switch over a range of ±10 dB. The normal setting for this control is the detented (click-
stopped) center position.
The reference level of the display is shown on the display window by the light gray horizontal line. The
actual reference level of the reference line corresponds to the dB level setting of the
D
B
m
/Spl
switch.
For example, the
D
B
m
/Spl
switch (coarse adjustment) is set to 90dB. The light gray line on the display
window represents a sound pressure level of 90dB if the 10dB
control (fine adjustment) is set at the cen
-
ter-detented position.
i
nput
3
A ¼" tip-ring-sleeve phone jack is used for connecting to balanced and unbalanced sources. Connect
unbalanced sources by using a tip-sleeve (2 conductor) plug inserted into this jack.
This input has an impedance of 10 kohms and is suitable for signal levels from -56dBu to +36dBu. An
input signal of 0dBu represents 100dB SPL.
i
nput
2
This is a standard audio (RCA) connector with an input impedance of 1 Mohm in parallel with 30 pF. The
particular combination of resistance and capacitance allows connecting a standard oscilloscope probe to
this input.
This input is suitable for signal levels from -56dBu to +36dBu. An input signal of 0dBu represents
100dBSPL.
i
nput
1
This is a st12 volt, phantom-powered, balanced microphone input. The phantom power supply is
intended for the AudioControl Industrial CM-10 or SPL-175 measurement microphones.
Ordinary dynamic microphones may also be connected directly to this input providing that they have a
balanced output. Unbalanced microphones may not be used. This input is suitable for acoustical levels at
the microphone ranging from 44dB SPL to 136dB SPL. The SPL display is only accurate if the
AudioControl Industrial CM-10 microphone is used, or if the external microphone matches the sensitivity
of the CM-10 microphone.
Features
2-3
