Audio Technica Unipoint U851A Specifications

• Designed for surface-mount
applications such as high­quality sound reinforcement,
professional recording,
television, conferencing and
other demanding sound pickup
situations

• PivotPoint

™

rotating output

connector allo

ws cable to exit
from either the rear or the
bottom of the microphone

• Superior off-axis rejection for
maximum gain before
f

eedback

• UniGuard

™

RFI-shielding

technology off

ers outstanding
rejection of radio frequency
interference (RFI)

• UniSteep

®

filter provides a steep low-frequency attenuation to

improve sound pickup without affecting voice quality

• Small-diameter UniPoint capsule near boundary eliminates phase
distortion and delivers clear, high-output performance

• Heavy die-cast case and non-slip silicon foam bottom pads
minimize coupling of surface vibration to the microphone

• Low-profile design with low-reflectance black finish for minimum
visibility

• Operates on battery or phantom power

The U851A requires 11-52V DC phantom power or a 1.5V AA
battery for operation. A battery need not be in place for phantom
power operation.

Batter

y installation: Remove the cap from the top of the power
module. Insert a fresh 1.5V AA battery (“+” end toward the cap
release button), then reassemble the power module. Alkaline
batter

ies are recommended for longest life. Remove the battery

during long-term storage.

Supplied as a cardioid, the U851A accepts interchangeab

le
elements to permit selection of angle of acceptance from 100° to
360°.

The microphone should be placed on a flat,
unobstructed mounting surface, with the front
of the microphone facing the sound source.
The sound source should not be below, or
higher than 60

° above, the plane of the

mounting surface.

Output from the power module’s XLRM-type connector 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.

An integral 80 Hz high-pass UniSteep

®

filter provides easy switching
from a flat frequency response to a low-end roll-off. The
roll-off position reduces the pickup of low-frequency ambient noise
(such as traffic, air-handling systems, etc.), room reverberation and
mechanically coupled vibrations.

A

void 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 a

voided.

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.

NOTE: Placing any object on a surface (such as a conference table)
before its finish is fully cured may result in damage to the finish.

8 kHz

Polar Pattern

SCALE IS 5 DECIBELS PER DIVISION

LEGEND

200 Hz

1 kHz
5 kHz

Frequency in Hertz

LEGEND

12" or more on axis
Roll-off

Frequency Response

Response in dB

Audio-Technica U.S., Inc., 1221 Commerce Drive, Stow, Ohio 44224

Audio-Technica Limited, Old Lane, Leeds LS11 8AG England

www.audio-technica.com

P51701 ©2005 Audi

o

-Technica U.S., Inc. Printed in U.S.A.

U851A CARDIOID CONDENSER BOUNDARY MICROPHONE

U851A SPECIFICATIONS

†

ELEMENT Fixed-charge back plate

permanently polarized condenser

POLAR PATTERN Half-cardioid

(cardioid in hemisphere above
mounting surface)

FREQUENCY RESPONSE 30-20,000 Hz
LOW FREQUENCY ROLL-OFF 80 Hz, 18 dB/octave
OPEN CIRCUIT SENSITIVITY –40 dB (10.0 mV) /

(Phantom / Battery) –41 dB (8.9 mV) re 1V at 1 Pa*

IMPEDANCE (Phantom / Battery) 200 ohms / 270 ohms
MAXIMUM INPUT SOUND LEVEL 133 dB / 123 dB SPL,

(Phantom / Battery) 1 kHz at 1% T.H.D.
DYNAMIC RANGE (typical) 111 dB / 101 dB,

(Phantom / Battery) 1 kHz at Max SPL

SIGNAL-TO-NOISE RATIO

1

72 dB, 1 kHz at 1 Pa*

PHANTOM POWER 11-52V DC, 2 mA typical
REQUIREMENTS

BATTERY TYPE 1.5V AA/UM3
BATTERY CURRENT / LIFE 0.4 mA / 1200 hours typical

(alkaline)

SWITCH Off, on-flat, on-roll-off
WEIGHT

MICROPHONE

8.6 oz (244 g)

POWER MODULE 4.9 oz (139 g)

DIMENSIONS

MICR

OPHONE

4.25" (108.0 mm) long,

3.31" (84.0 mm) maximum width,

0.91" (23.0 mm) height

POWER MODULE 3.31" (84.0 mm) H x

2.48" (63.0 mm) W x

0.87" (22.0 mm) D

OUTPUT CONNECTOR Integral 3-pin XLRM-type
(po

wer module)

CABLE 25.0' (7.6 m) long (per

manently
attached to microphone), 0.13"
(3.2 mm) diameter, 2-conductor,
shielded cable with TA3F-type
connector

OPTIONAL INTERCHANGEABLE UE-H hypercardioid (100°);
ELEMENTS UE-O omnidirectional (360°)

ACCESSORIES FURNISHED AT8531 power module; battery;

soft protectiv

e pouch

†

In the interest of standards de

velopment, A.T.U.S. offers full details on its test

methods to other industry professionals on request.

*1 Pascal = 10 dynes/cm

2

= 10 microbars = 94 dB SPL

1

T

ypical, A-weighted, using Audio Precision System One.

Specifications are subject to change without notice.

60°

IDEAL
WORKING
ANGLE