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SCALE IS 5 DECIBELS PER DIVISION
Polar Pattern
200 Hz
LEGEND
5 kHz
1 kHz
8 kHz
12" or more on axis
LEGEND
Roll-off
Frequency in Hertz
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
P51967 ©2007 Audio-Technica U.S., Inc. Printed in Japan
• Clip-on lavalier mic provides crisp, full-sounding voice pickup
• Also excels as an instrument mic, especially for pickup of
acoustic guitar with included AT8444 instrument adapter
• Excellent gain before feedback and suppression of background
noise
• UniSteep
®
filter provides a steep low-frequency attenuation to
improve sound pickup without affecting voice quality
• Operates on battery or phantom power
For use as a lavalier, attach the microphone about six inches below
the chin. Anticipate movements that may cause the microphone to
rub against or be covered by clothing, and position the microphone
to avoid it.
The AT831b 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.
Battery 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
batteries are recommended for longest life. Remove the battery
during long-term storage.
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.
To avoid phase cancellation and poor sound, all mic cables must
be wired consistently: Pin 1-to-Pin 1, etc.
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 microphone’s sensitivity to popping in close
vocal use. It also reduces the pickup of low-frequency ambient
noise (such as traffic, air-handling systems, etc.), room reverberation
and mechanically coupled vibrations.
The microphone is RoHS compliant–free from all substances
specified in the EU directive on hazardous substances.
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.
AT831b SPECIFICATIONS
†
ELEMENT Fixed-charge back plate
permanently polarized
condenser
POLAR PATTERN Cardioid
FREQUENCY RESPONSE 40-18,000 Hz
LOW FREQUENCY ROLL-OFF 80 Hz, 18 dB/octave
OPEN CIRCUIT SENSITIVITY –44 dB (6.3 mV) /
(Phantom / Battery) –46 dB (5.0 mV) re 1V at 1 Pa*
IMPEDANCE (Phantom / Battery) 200 ohms / 270 ohms
MAXIMUM INPUT SOUND LEVEL 135 dB / 121 dB SPL,
(Phantom / Battery) 1 kHz at 1% T.H.D.
DYNAMIC RANGE (typical) 106 dB / 92 dB,
(Phantom / Battery) 1 kHz at Max SPL
SIGNAL-TO-NOISE RATIO
1
65 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 (less cable and accessories)
MICROPHONE 2.8 g (0.1 oz)
POWER MODULE 139 g (4.9 oz)
DIMENSIONS
MICROPHONE 25.0 mm (0.98") long,
10.2 mm (0.40") diameter
POWER MODULE 84.0 mm (3.31") H x
63.0 mm (2.48") W x
22.0 mm (0.87") D
OUTPUT CONNECTOR Integral 3-pin XLRM-type
(power module)
CABLE 1.8 m (6') long (permanently
attached to microphone),
2.6 mm ( 0.10") diameter,
2-conductor, shielded cable
with TA3F-type connector
ACCESSORIES FURNISHED AT8531 power module;
AT8417 clothing clip;
AT8444 instrument adapter;
AT8116 windscreen; battery;
protective carrying case
†
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/cm
2
= 10 microbars = 94 dB SPL
1
Typical, A-weighted, using Audio Precision System One.
Specifications are subject to change without notice.
AT831b
MINIATURE CARDIOID
CONDENSER MICROPHONE