Audio Technica U851RO Owner's manual

unipoint® microphones
Omnidirectional Condenser Boundary Microphone
U851RO
Features
• PivotPoint® rotating output connector allows cable to exit
from either the rear or the bottom of the microphone
• Small-diameter UniPoint omnidirectional capsule near
boundary eliminates phase distortion and delivers clear,
high-output performance
• Superior off-axis rejection for maximum gain before feedback
• UniGuard® RFI-shielding technology offers outstanding rejection
of radio frequency interference (RFI)
• Self-contained electronics eliminate need for external
power module
• UniSteep® lter provides a steep low-frequency attenuation
to improve sound pickup without affecting voice quality
• Available interchangeable elements permit angle of acceptance
from 100° to 360°
• Heavy die-cast case and non-slip silicon foam bottom pads
minimize coupling of surface vibration to the microphone
• Low-prole design with low-reectance nish for minimum
visibility
U851RO Description
The U851RO is a wide-range condenser microphone with an
omnidirectional polar pattern. It is designed for surface-mount
applications such as high-quality sound reinforcement, conferencing,
professional recording, television and other demanding sound pickup
applications.
The microphone requires 11V to 52V phantom power for operation.
The microphone is equipped with UniGuard® RFI-shielding technology,
which offers outstanding rejection of radio frequency interference (RFI).
The microphone’s omnidirectional polar pattern provides a 360° angle of
acceptance (omni in hemisphere above mounting surface). Additional
interchangeable elements with cardioid (120°) and hypercardioid (100°)
pickup patterns are available.
The microphone includes a 7.6 m (25') output cable terminating in special
TA3F-type and XLRM-type connectors designed to optimize RFI
immunity. The output of the microphone is a TB3M-type connector. The
microphone is equipped with Audio-Technica's unique PivotPoint® rotating
output connector.
A switch permits choice of at response or low-frequency roll-off (via
integral 80 Hz high-pass UniSteep® lter) to help control undesired
ambient noise.
The microphone's heavy die-cast case and non-slip silicon foam
bottom pads minimize coupling of surface vibration to the microphone.
The microphone includes a soft protective pouch and features a low-
reectance black nish.
Installation and Operation
The U851RO requires 11V to 52V phantom power for operation.
Output is low impedance (Lo-Z) balanced. The signal appears across Pins
2 and 3; Pin 1 is ground (shield). Output phase is “Pin 2 hot”— positive
acoustic pressure produces positive voltage at Pin 2.
The microphone should be placed on a at, unobstructed mounting
surface. The sound source should not be below the plane of the
mounting surface.
An integral 80 Hz high-pass UniSteep® lter provides easy switching
from a at frequency response to a low-end roll-off. The roll-off position
reduces the pickup of low-frequency ambient noise (such as trafc, air-
handling systems, etc.), room reverberation and mechanically coupled
vibrations. To engage the UniSteep® lter, slide the switch toward the
“bent” line.
The microphone’s PivotPoint® rotating output connector allows the cable
to exit from either the rear or the bottom of the microphone without the
need for tools or disassembly.
Avoid leaving the microphone in the open sun or in areas where
temperatures exceed 110° F (43° C) for extended periods. Extremely high
humidity should also be avoided.
Note: Audio-Technica has developed a special RFI-shielding mechanism,
which is an integral part of the connectors in the UniPoint® line. If you
remove or replace the connector, you may adversely affect the unit's
RFI immunity. Audio-Technica offers a crimp tool (ATCT) and RFI shields
that enable you to shorten the cable and correctly reinstall the connector
while maintaining the highest level of RFI immunity.
Note: Placing any object on a surface (such as a conference table) before
its nish is fully cured may result in damage to the nish.

U851RO
Specications
Audio-Technica U.S., Inc., 1221 Commerce Drive, Stow, Ohio 44224
Audio-Technica Limited, Old Lane, Leeds LS11 8AG England
©2010 Audio-Technica U.S., Inc. audio-technica.com P52260
In the interest of standards development, A.T.U.S. offers full
details on its test methods to other industry
professionals on request.
1 Pascal = 10 dynes/cm2 = 10 microbars = 94 dB SPL
1 Typical, A-weighted, using Audio Precision System One.
Specications are subject to change without notice.
LEGEND
200 Hz
1 kHz
5 kHz
8 kHz
SCALE IS 5 DECIBELS PER DIVISION
240˚
180˚
210˚
270˚
300˚
330˚ 0˚
150˚
120˚
90˚
30˚
60˚
12" or more on axis
LEGEND
Frequency in Hertz
Response in dB
10 dB
100
50 200 10k 5k
1k
500 2k 20k
Roll-off
frequency response: 30–20,000 Hz
polar pattern
Fixed-charge back plate, permanently
polarized condenser
Omnidirectional in hemisphere above
mounting surface
30-20,000 Hz
80 Hz, 18 dB/octave
–31 dB (28.2 mV) re 1V at 1 Pa
200 ohms
132 dB SPL, 1 kHz at 1% T.H.D.
111 dB, 1 kHz at Max SPL
73 dB, 1 kHz at 1 Pa
11-52V DC, 4 mA typical
Flat, roll-off
262 g (9.2 oz)
108.0 mm (4.25") maximum length,
84.0 mm (3.31") maximum width,
23.0 mm (0.91") maximum height
TB3M-type
7.6 m (25.0') long, 3.2 mm (0.13")
diameter, 2-conductor, shielded cable with
TA3F-type and XLRM-type connectors
UE-C cardioid (120°)
UE-H hypercardioid (100°)
Soft protective pouch
Element
Polar pattern
Frequency response
Low frequency roll-off
Open circuit sensitivity
Impedance
Maximum input sound level
Dynamic range (typical)
Signal-to-noise ratio1
Phantom power requirements
Switch
Weight
Dimensions
Output connector
Cable
Optional interchangeable elements
Accessory furnished
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