The UEM81S is a pre-polarized condenser microphone used for stage,
studio, video and broadcast applications. The UEM81S is conveniently
powered by one AA battery; therefore it is not dependent on phantom
power for operation. Known for its exceptional sound quality, accurate
response and ability to pick up from a distance, the UEM81S is designed
to be aimed directly at the sound source and can help capture those
“hard to get to” places in a theatre, on a stage, in a sporting event or in
the outdoors.
Instrument Condenser
Characterized with a uniformly controlled supercardioid polar pattern, the
UEM81S is designed to capture the acoustics of a vocal or instrument
while at the same time isolating it from the rest of the ambient noise on
stage or in the room. With a wide frequency range of 20 Hz – 20 kHz,
the UEM81S is equipped with an on-off switch as well as with a bass
roll-off switch.
The UEM81S is very easy to position, durable and manufactured with
high standards and tight tolerances. Roadworthy construction includes
a machined aluminum body and capsule housing, black e-coat finish,
interchangeable threaded capsule and snap to fit composite clip.
Modular preamp supply with on-off switch and bass roll-off filter (PS-81)
Modular cardioid capsule (CPS81S)
Tension-fit clip (MC81)
External Foam Windscreen (WS81S)
20’ XLR-XLR mic cable
1 AA Battery
Vinyl carrying box
Live sound, location recording, video, film
Vocals - lead, background, group
Acoustic instruments
Overheads, room ambience
DCLIP - Heavy duty tension clip
SMT-25 - Shockmount suspension clip
TRIPOD - Tripod mic stand
CPS-81C - Modular cardioid capsule
UEM81S on MC81
“Shotgun” pick up pattern
Excellent sonic quality
AA Battery operated
Highly sensitive
On-off switch, bass roll-off filter
Lightweight, easy to position
Modular capsule
Pre-Polarized Condenser
20 Hz - 20 kHz
600 Ohms
4 mV / Pa
24 dB (A weighted)
79 dB
AA Battery
≥128 dB
Positive pressure on
diaphragm produces
positive voltage on pin
2 relative to pin 3
Aluminum /
Black E-Coat
396.9 g / 14 ounces
435 mm / 17.1 inches
The microphone shall be a back plate pre-polarized condenser with a modular capsule and supercardioid polar pattern. The microphone shall operate on 3 volts DC (AA Battery) and the nominal
output impedance shall be equal to 600 ohms at 1 kHz. The microphone shall have switches for
on-off function and bass roll-off filter. The microphone shall have a sensitivity of 4 mV / Pa at 1 kHz
and a maximum SPL level of ≥128 dB with a THD of 0.5%. The microphone shall be machined
from aluminum brass with dimensions of 21 mm in diameter and 435 mm in length. The microphone
shall be the Audix UEM81S.
Transducer Type
Frequency Response
Polar Pattern
Output Impedance
Open Circuit Sensitivity
Equivalent Noise Level
Signal to Noise Ratio
Power Requirements
Maximum SPL
The UEM81S is a low impedance microphone and should be plugged into the mic level input of
your mixer, console, or recording device. The UEM81S does not require phantom power as it is
powered by one AA battery and will operate for 500-1000 hours under normal useage. Phantom
power will not adversely effect the UEM81S as long as batteries are installed. If batteries are
not installed and phantom power is engaged, you may experience frequency loss in the bass
frequencies and higher self noise.
Avoid plugging or unplugging the microphone from a PA system unless the channel is muted or the
volume of the system is turned down. Failure to do so may result in a loud “popping” noise which
could seriously damage the speakers in the PA system.
On-Off Switch: The switch must be in the ON position in order for the microphone to operate.
Avoid using the switch unless the PA system is muted or the volume turned down. When the
microphone is not in use, be sure to turn the microphone OFF in order to conserve battery power.
M/V Bass Roll-Off Switch: This feature gently rolls off the bass frequencies starting at 150 Hz
which is very helpful in reducing “boominess” for voice. This feature is engaged when the switch is
in the “150Hz” position. For full range frequency response for musical instruments put the switch
in the “Flat” position.
Replacing the battery: If the microphone begins to sound distorted or weak, it is time to change
the battery. Battery is housed in bottom section of the mic above the XLR connector. Unscrew the
housing to replace the battery.
Windscreen: The windscreen can be utilized to help control wind noise, breath noise, popping
and sibilance sounds.
The UEM81S is an excellent utility microphone for audio and video applications as it will pick up
and isolate sound from a distance. Depending on the gain structure of the device it is plugged into
and noise conditions surrounding the microphone, the UEM81S will have an effective reach of 25’
or more.
*Further miking techniques may be found on our website at
***All specifications subject to change without notice.
This microphone is under warranty for
a period of 3 years from any and all
manufacturing defects. Should your
microphone fail in any way, please contact the Audix Service department at
503-682-6933. A Return Authorization
number is required before returning
any products.
The UEM81S is manufactured to exacting
specs with roadworthy construction. However,
the capsule is highly sensitive and should be
handled with care. Avoid extreme temperatures
and be sure to store your microphone in the
pouch provided when not in use. Moisture of
any kind can adversely affect the sound and
performance of your microphone.
To register your
microphone, please visit Call: 503-682-6933 Fax: 503-682-7114
Audix Corporation 9400 SW Barber Street, Wilsonville, OR 97070
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