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PRO 45 and PRO 45W
REMOTE-POWERED
CARDIOID CONDENSER
HANGING MICROPHONES
Frequency in Hertz
Response in dB
10 dB
20k
10k
5k
2k
1k
500
200100
50
LEGEND
12" or more on axis
Frequency Response
The microphone element is enclosed in a
rugged housing with a low-reflectance black
finish. The microphone is also available in
white as the PRO 45W, with a white-finished
microphone housing, windscreen, cable and
steel hanger, for applications where the
microphone must be hung against a light
background.
Operation and Maintenance
The PRO 45 is ideal for suspension over
choirs, instrumental groups or theater stages.
A uniform 120° angle of acceptance provides
well-balanced audio pickup. The microphone
should be located forward of the front-most
source, above the rear-most source, and
“aimed” between them (Fig. 1). Increasing the
height of the mic above the sources will tend
to equalize sound levels between them, but
may also increase background/reverberant
sound pickup. Whenever possible, the distance
from the mic to the rear-most pickup should
be no more than twice the distance to the
front source, to maintain front-to-rear balance
(Fig. 1).
Width of pickup is approximately three times
the distance to the closest performer. If addi-
tional mics are needed for wide sources, they
should not be closer together laterally than
three times the distance to the front source,
to avoid phase cancellation (Fig. 2).
To orient in the proper direction, twist the
microphone housing
slightly
in its wire holder
(clockwise rotation moves the microphone to
the right; counterclockwise rotation moves it
to the left). The provided AT8146 windscreen
simply slips over the head of the microphone,
effectively reducing noise from wind or venti-
lation air currents.
Output is low impedance balanced. The output
connector mates with XLRF-type connectors.
The balanced signal appears across Pins 2
and 3, while the ground (shield) connection is
Pin 1. Output is phased so that positive
acoustic pressure produces positive voltage at
Pin 2 in accordance with industry convention.
DC phantom power (9-52 volts) must be
applied equally to Pins 2 and 3, with the ground
for the power supply connected to Pin 1. This
can be provided by a console or mixer with
built-in phantom voltage or with the addition
of an in-line phantom power supply, such as
the recommended Audio-Technica CP8506
and AT8801 power supplies.
If an extension cable is necessary, AT8314
cable (or equal) should be used. Regardless
of cables used, it is important that both ends
of each cable are wired consistently, with the
shield always connected to Pin 1 at both
ends, Pin 2 connected to Pin 2, and Pin 3 to
Pin 3.This will ensure that all microphones are
electrically in phase and reduce problems of
uneven response and sound cancellation
when two microphones are used close to each
other.
The high sensitivity of the PRO45 ensures
useful output and an excellent match to most
mixer, tape recorder and amplifier inputs. It
will provide undistorted output even in sound
fields as loud as 134 dB SPL. However, due
to the high sensitivity, in some instances it
may be possible to overload sensitive input
stages. If distortion occurs,
first
check for
input
overload. In such cases, an attenuator
such as the Audio-Technica AT8202 may be
required between the mic and the electronics
input. (Also, many mixers provide “input pad”
switches to reduce mic-input signal levels.)
While a modern condenser microphone is not
unduly sensitive to the environment, tempera-
ture extremes can be harmful. Exposure to
high temperatures can result in gradual and
permanent reduction of the output level.Avoid
leaving the microphone in the open sun or in
areas where temperatures exceed 110° F
(43° C) for long periods of time. Extremely
high humidity should also be avoided.
Description
The PRO45 is a wide-range condenser micro-
phone with a cardioid (unidirectional) polar
pattern. It was designed for high-quality sound
reinforcement and other demanding sound
pickup applications. The PRO 45 is furnished
with a vinyl-coated steel hanger that allows it
to be positioned inconspicuously over a choir,
orchestra, stage, etc., for low-profile situations.
The PRO 45 features a 25' (7.6 m) perma-
nently-attached miniature cable with an
XLRM-type connector, which allows it to be
plugged directly into an XLRF-type jack or
cable connector.The unit’s integral electronics
can be powered from any external 9V to 52V
DC phantom power source.
Audio-Technica design engineers have utilized
the newest low-mass technology in the quest
for superior performance.The charge is now on
the fixed back plate, rather than the moving
element.With the A-T fixed-charge “back plate”
construction, a gold-vaporized diaphragm just
2 microns thick (about 0.000079") can be
used. This reduces moving mass substantially,
improving frequency response and transient
response while reducing distortion.
LESS THAN 2 TIMES “X”
DISTANCE “X”
12 0°
ANGLE OF
ACCEPTANCE
MIC A MIC B
3 TIMES
DISTANCE “X”
120°120
°
Fig. 1 Fig. 2