Audio Technica AT891R Architects And Engineers Specifications
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Brand: Audio Technica
Category: Microphone
Type: Product information for Audio Technica UniPlate AT891R
Pages: 2 (0.13 Mb)
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Description
The AT891R is a wide-range condenser
microphone with an hemi-cardioid (half-space
cardioid) polar pattern. It was designed for
surface-mount applications in high-quality
sound reinforcement, conferencing and other
demanding sound pickup situations. Its small
size makes the AT891R suitable for use in
applications where minimum visibility is
required.
The AT891R features a touch-sensitive on/off
switch offering three choices of switching
modes: on/off, momentary on and momentary
off. A switch located on the bottom of the
microphone selects the desired mode. A red
LED on the unit indicates when the micro-
phone is “on.”
Positioning a properly designed miniature
microphone centrally on a large, flat, unob-
structed surface yields several distinct advan-
tages. Directionality is increased by 3 dB,
promoting enhanced gain before feedback
and further suppression of ambient noise.
Sensitivity is increased for improved signal-to-
noise ratio. Phase distortion due to reflected
sound energy from the boundary itself is
eliminated.
The AT891R can be powered from any external
11V to 52V DC phantom power supply. A
switch on the bottom of the unit permits
choice of flat response or low-frequency roll-
off to help control undesired ambient noise.
A 25' (7.6 m) shielded cable with TA3F and
XLRM-type connectors is provided for use
between the microphone and electronics
inputs.
The microphone is enclosed in a rugged
case and protected by two layers of perforated
steel. The rubber non-slip bottom pad
minimizes mechanical coupling of surface
vibrations to the microphone. The low-profile
housing has a low-reflectance black finish.
Installation and Operation
The symmetry and area of the mounting
surface directly affect the sensitivity of the
boundary microphone at low frequencies.
Ideally, the mounting surface should be circu-
lar; however, square or rectangular surfaces
are most often used. If the mounting surface
is rectangular, the smaller dimension tends to
determine low-frequency cutoff. The micro-
phone should be centered on the surface and
positioned with the front of the microphone
facing the sound source along the larger
dimension of the mounting surface. The
sound source should not be below, or higher
than 60˚ above, the plane of the mounting
surface.
The AT891R requires 11-52V phantom power
which operates the microphone and switch
circuitry. The electronics in the microphone
take up to 30 seconds to stabilize after
power is applied; during this start-up period,
some thumps or other sonic disturbances
may be heard upon switching if the system is
“live.”
A touch-sensitive on/off switch on the
AT891R offers three choices of switching
modes. A switch located on the bottom of
the microphone selects the desired mode.
TOUCH ON/OFF:
Touch the on/off switch
once to turn mic on, touch again to turn off.
MOM. (Momentary) ON:
Mic is on only
while the switch is being touched (“press to
talk”).
MOM. OFF:
Mic is off only while the
switch is being touched (“press to mute”
function). The red LED on the top of the unit
indicates when the microphone is “on.”
Output is low impedance balanced. The bal-
anced 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.
While a modern condenser microphone is
not unduly sensitive to the environment,
temperature extremes can be harmful. 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.
Architects and Engineers Specifications
The microphone shall be a fixed-charge
condenser with a unidirectional polar
pattern designed for use in surface-mount
boundary applications. The frequency
response shall be 30 Hz to 10,000 Hz. The
microphone shall operate from an external
11V to 52V DC phantom power source.
Nominal open-circuit output voltage shall be
22.4 mV at 1 kHz, 1 Pascal. Output shall be
low impedance balanced (200 ohms).
The microphone shall have a touch-sensitive
switch that may be set for any of three
switching modes: on/off, momentary on,
momentary off. The microphone shall include
a switch for low-frequency roll-off.
A 25' (7.6 m) cable with TA3F to XLRM-type
connectors shall be supplied for connection
between the microphone and electronics
input. The microphone shall have a maximum
width of 2.87" (73.0 mm) and a maximum
length of 4.33" (110.0 mm). Weight shall be
2.6 oz (74 grams). The microphone shall be
housed in a rugged case with a two-layer
perforated steel grille. Finish shall be low-
reflectance black.
The Audio-Technica AT891R is specified.
AT891R
UNIDIRECTIONAL
CONDENSER
BOUNDARY
MICROPHONE
WITH SWITCH
Frequency Response
LEGEND
Roll-off
12" or more on axis (flat)
Frequency in Hertz
Response in dB
10 dB
20k
10k
5k
2k
1k
500
200100
50
60°
IDEAL
WORKING
ANGLE