Frequency in Hertz
Response in dB
10 dB
20k
10k
5k
2k
1k
500
200100
50
Frequency Response
LEGEND 12" or more on axis
• Ideal for close-up vocals, overheads, piano, and strings
•Cardioid polar pattern reduces pickup of sounds from the sides
and rear, improving isolation of desired sound source
•Proximity effect provides added warmth when used close up
• Large protective screen reduces “popping” and sibilant distortion
•Operates on battery or phantom power
The AT813a requires 9V to 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: Unscrew the lower section of the microphone
body, just below the nameplate.Insert a fresh 1.5V AA battery
in the handle compartment (“+” end up), then reassemble the
microphone. Alkaline batteries are recommended for longest life.
Remove the battery during long-term storage.
Output from the microphone’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.
The high sensitivity of the AT813a assures useful output and an
excellent match to most input sources. In some cases, however, an
attenuator such as the Audio-Technica AT8202 may be required
between the microphone and preamplifier to avoid overloading
sensitive input stages.
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.
AT813a SPECIFICATIONS†
ELEMENT Fixed-charge back plate
permanently polarized
condenser
POLAR PATTERN Cardioid
FREQUENCY RESPONSE 30-20,000 Hz
OPEN CIRCUIT SENSITIVITY –44 dB (6.3 mV) /
(Phantom / Battery) –45 dB (5.6 mV) re 1V at 1 Pa*
IMPEDANCE (Phantom / Battery) 200 ohms / 270 ohms
MAXIMUM INPUT SOUND LEVEL 137 dB / 123 dB SPL,
(Phantom / Battery) 1 kHz at 1% T.H.D.
SIGNAL-TO-NOISE RATIO170 dB, 1 kHz at 1 Pa*
DYNAMIC RANGE (typical) 113 dB / 99 dB,
(Phantom / Battery) 1 kHz at Max SPL
PHANTOM POWER 9-52V DC, 2 mA typical
REQUIREMENTS
BATTERY TYPE 1.5V AA/UM3
BATTERY CURRENT / LIFE 0.4 mA / 1200 hours typical
WEIGHT (less accessories) 7.1 oz (200 g)
DIMENSIONS 7.60" (193.0 mm) long,
1.98" (50.3 mm) maximum
diameter
OUTPUT CONNECTOR Integral 3-pin XLRM-type
ACCESSORIES FURNISHED AT8405a stand clamp for 5/8"-27
threaded stands; battery; soft
protective pouch
†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
1Typical, A-weighted, using Audio Precision System One.
Specifications are subject to change without notice.
Audio-Technica U.S., Inc., 1221 Commerce Drive, Stow, Ohio 44224
Audio-
Technica Limited, Old Lane, Leeds LS11 8AG England
www.audio-technica.com
P51653-EN ©2004 Audio-Technica U.S., Inc. Printed in Japan
AT813a CARDIOID CONDENSER MICROPHONE
200 Hz
1 kHz
5 kHz
8 kHz
LEGEND
Same as 1 kHz
Polar Pattern
SCALE IS 5 DECIBELS PER DIVISION
90
60
120
30
150
210
240
270
300
330
180
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