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The DOD RTA Series II also has its own internal pink noise generator and level
control. Pink noise is defined as an audio signal that contains all frequencies
at equal energy levels. For this reason, pink noise sounds a lot like static.
Pink noise is useful when setting up P.A. systems and audio systems when
you need to see the frequency response of the system.
On the rear of the unit is an auxiliary microphone jack for use with other mea-
surement microphones, and an output jack for the pink noise generator.
When the pink noise is off, this jack acts as an audio output so that the signal
may be looped through the RTA and monitored during a performance. There
is also an input jack that allows you to directly analyze equipment in a system.
F
RONT
P
ANEL
C
ONTROLS
Power Switch: Applies power to the RTA.
Display LEDs: Each vertical column of LEDs displays the signal level within
that frequency band. Each frequency is on a 1/3rd octave ISO centered point
from 20 Hz to 20kHz.
Input Level Control: This control sets the input level from the calibrated
microphone input jack, the line level input jack, or the auxiliary microphone
input jack. Use this control to set the response of the display to a useful
range.
Resolution Switch: This push-push switch selects the size of step between
LEDs to either 1 dB or 3 dB. This effectively widens or narrows the window
that the RTA shows, giving you a wider or narrower view of the incoming sig-
nal.
Pink Noise Switch: This push-push switch turns the pink noise generator on
or off. To prevent damage to your audio system, be sure to turn down your
audio system’s gain control before turing on the pink noise generator.
Pink Noise Level Control: This rotary potentiometer sets the output level of
the pink noise generator. To prevent damage to your audio system, be sure to
set this control to minimum before turning on the pink noise generator.
Calibrated Microphone Input Jack: This jack supplies power to the calibrat-
ed microphone. Plug only the calibrated microphone provided with the RTA
into the jack on the front panel of the RTA. Other microphones may be dam-
aged or give inaccurate readings.
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