Audio-Technica U891Rx Leaflet

Page of 2
unipoint
®
 microphones
U
891Rx & U891RWx
Cardioid Condenser Boundary Microphones with Switch 
Features
•  Activation switch can be set to any of three operating modes:
 “press-on/press-off,” “press-to-talk” and “press-to-mute”
•  PivotPoint
®
rotating output connector allows cable to exit from
 either the rear or the bottom of the microphone
•  Small-diameter UniPoint cardioid capsule near boundary
 eliminates phase distortion and delivers clear, high-output
 performance
•  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
•  Available interchangeable elements permit angle of acceptance
 from 100° to 360°
•  Heavy die-cast case and non-slip silicone foam bottom pads
 minimize coupling of surface vibration to the microphone
•  Low-profile design with low-reflectance finish for minimum
 visibility
•  Available in two colors: black (U891Rx) and white (U891RWx)
Description
The U891Rx is a wide-range condenser microphone with a cardioid polar 
pattern. It is designed for surface-mount applications such as high-quality 
sound reinforcement, conferencing, professional recording, and other 
demanding sound pickup applications.
The microphone features an activation switch that can be set (via a 
switch on the bottom of the microphone) to any of three operating 
modes: “press-on/press-off,” “press-to-talk” and “press-to-mute”.
The microphone requires 11V to 52V phantom power for operation.
The microphone is equipped with UniGuard
®
 RFI-shielding technology, 
which offers outstanding rejection of radio frequency interference (RFI).  
The microphone’s cardioid polar pattern provides a 120° angle of 
acceptance (cardioid in hemisphere above mounting surface). Additional 
interchangeable elements with omnidirectional (360°) and hypercardioid 
(100°) pickup patterns are available.
The microphone includes a 7.6 m (25') output cable terminating in 
special TA3F-type and XLRM-type connectors designed to optimize RFI 
immunity. The output of the microphone is a TB3M-type connector. The 
microphone is equipped with Audio-Technica’s unique PivotPoint
®
 rotating 
output connector.
A switch permits choice of flat response or low-frequency roll-off (via 
integral 80 Hz high-pass UniSteep
®
 filter) to help control undesired 
ambient noise. 
The microphone's heavy die-cast case and non-slip silicone foam 
bottom pads minimize coupling of surface vibration to the microphone. 
The microphone includes a soft protective pouch and features a low-
reflectance black finish. It is also available in white as the U891RWx.
Installation and Operation
The U891Rx requires 11V to 52V phantom power for operation.
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, 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.
An activation switch on the microphone offers three choices of switching 
modes. The SW. FUNCTION switch located on the bottom of the 
microphone selects the desired mode. TOUCH ON/OFF: Press the on/
off switch once to turn the microphone on; press again to turn off. MOM. 
ON (momentary on): Microphone is on only while the switch is being 
pressed (“press to talk”). MOM. OFF (momentary off): Microphone is off 
only while the switch is being pressed (“press to mute”). The red LED on 
the top of the unit indicates when the microphone is “on.”
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. To engage the UniSteep
®
 filter, slide the switch toward the 
“bent” line.
The microphone’s PivotPoint
®
 rotating output connector allows the cable 
to exit from either the rear or the bottom of the microphone without the 
need for tools or disassembly.
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 a cardioid polar pattern with 
a uniform 120° angle of acceptance (cardioid in hemisphere above 
mounting surface) and a frequency response of 30 Hz to 20,000 Hz. 
It shall be capable of accepting optional interchangeable elements for 
additional polar patterns. The microphone shall operate from an external 
60°
IDEAL
WORKING
ANGLE