unipoint
®
microphones
Omnidirectional Condenser Boundary Microphone
U841A
Features
• Small-diameter UniPoint
®
omnidirectional capsule near boundary
eliminates phase distortion and delivers clear, high-output
performance
• Offers the convenience of battery or phantom power operation
• 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
®
filter provides a steep low-frequency attenuation to
improve sound pickup without affecting voice quality
• 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 finish for minimum
visibility
Description
The U841A 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 or a 1.5V AA
battery for operation. A battery need not be in place for phantom power
operation.
The microphone is equipped with UniGuard
®
RFI-shielding technology,
which offers outstanding rejection of radio frequency interference (RFI).
The microphone includes a 7.6 m (25') permanently attached miniature
cable. Its free end connects to the provided AT8531 power module via a
special TA3F-type connector to optimize RFI immunity. The output of the
power module is a 3-pin XLRM-type connector.
A 3-position switch in the power module permits choice of off, on/flat
response or on/low-roll-off (via integral 80 Hz high-pass UniSteep
®
filter).
The roll-off position reduces the pickup of low-frequency ambient noise.
The microphone comes equipped with a power module, a battery and a
soft protective pouch. The microphone's heavy die-cast case and non-slip
silicon foam bottom pads minimize coupling of surface vibration to the
microphone. The microphone features a low-reflectance black finish.
Installation and Operation
The U841A requires 11V to 52V phantom power or a 1.5V AA battery for
operation. A battery need not be in place for phantom power operation.
To install the battery, 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. For longest battery life, the switch
should remain off except when the microphone is in use. Alkaline
batteries are recommended for longest life. Remove the battery during
long-term storage.
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 flat, unobstructed mounting
surface. The sound source should not be below the plane of the
mounting surface.
A 3-position switch in the power module permits choice of off, on/
flat response, or on/low-roll-off (via integral 80 Hz high-pass UniSteep
®
filter). 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. To engage the UniSteep
®
filter, slide
the switch toward the “bent” line. To turn the microphone on without
engaging the UniSteep
®
filter, slide the switch toward the flat line.
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 finish is fully cured may result in damage to the finish.
Architect’s and Engineer’s Specifications
The microphone shall be a fixed-charge condenser designed for use in
surface-mount applications. It shall have an omnidirectional polar pattern
in the hemisphere above the mounting surface and a frequency response
of 30 Hz to 20,000 Hz. The microphone shall operate from an external
11V to 52V DC phantom power source or, alternatively, from a 1.5V AA/
UM3 battery. It shall be capable of handling sound input levels up to
132 dB (phantom) or 122 dB (battery) with a dynamic range of 111 dB
(phantom) or 101 dB (battery). Nominal open-circuit output voltage shall
be 11.2 mV (phantom) or 10.0 mV (battery) at 1V, 1 Pascal. Output shall be
low impedance balanced (200 ohms – phantom, 270 ohms – battery). It
shall offer outstanding rejection of radio frequency interference (RFI).
The microphone shall have a 7.6 m (25') permanently attached miniature
cable terminating in a special TA3F-type output connector designed to
optimize RFI immunity. The output connector shall connect to a TB3M-
type jack on the included power module. The power module shall house
the battery, and shall contain a switch that permits choice of off, on/flat
response, or on/low-roll-off (80 Hz). The output of the power module shall
be a 3-pin XLRM-type connector.
The microphone shall have a diameter of 65.0 mm (2.56") and a
maximum height of 15.1 mm (0.59"). Weight shall be 78 grams (2.8 oz).
The microphone shall be housed in a die-cast case with a perforated steel
grille. Finish shall be low-reflectance black. The microphone shall include
a power module, a battery and a soft protective pouch.
The Audio-Technica U841A is specified.
