Product Description
Audio-Technica U851RB Cardioid Condenser Boundary Microphone
The phantom-powered U851Rb cardioid condenser boundary microphone offers outstanding speech intelligibility and transparent sound quality for surface-mount applications such as high-quality sound reinforcement, professional recording, television, conferencing and other demanding sound pickup situations. The microphone is equipped with a PivotPoint® rotating output connector, UniSteep® filter and UniGuard® RFI-shielding technology. It accepts interchangeable condenser elements, available separately in hypercardioid and omnidirectional polar patterns. With a heavy die-cast case and silicon foam bottom pads to minimize coupling of surface vibration to the microphone, the U851Rb is equipped with self-contained electronics, eliminating the need for an external power module. Threaded inserts on the bottom of the microphone allow it to be mounted with screws for increased security.
Available in two colors: black (U851Rb) and white (U851RWb).
Features:
- Cardioid condenser boundary microphone
- Designed for surface-mount applications such as high-quality sound reinforcement, professional recording, television, conferencing and other demanding sound pickup situations
- Superior off-axis rejection for maximum gain before feedback
- PivotPoint® rotating output connector allows cable to exit from either the rear or the bottom of the microphone
- Small-diameter UniPoint® element near boundary eliminates phase distortion and delivers clear, high-output performance
- Available interchangeable elements permit angle of acceptance from 100° to 360°
- UniGuard® RFI-shielding technology offers outstanding rejection of radio frequency interference (RFI)
- Self-contained electronics eliminate need for external power module
- 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
- Threaded inserts on bottom of microphone allow it to be mounted with screws for increased security
- Available in two colors: black (U851Rb) and white (U851RWb)
Specifications:
| ELEMENT | Fixed-charge back plate, permanently polarized condenser |
| POLAR PATTERN | Cardioid |
| FREQUENCY RESPONSE | 20-20,000 Hz |
| LOW FREQUENCY ROLL-OFF | 80 Hz, 18 dB/octave |
| OPEN CIRCUIT SENSITIVITY | -34 dB (19.9 mV) re 1V at 1 Pa |
| IMPEDANCE | 50 ohms |
| MAXIMUM INPUT SOUND LEVEL | 134 dB SPL, 1 kHz at 1% T.H.D. |
| DYNAMIC RANGE (typical) | 108 dB, 1 kHz at Max SPL |
| SIGNAL-TO-NOISE RATIO | 68 dB, 1 kHz at 1 Pa, A-weighted |
| PHANTOM POWER REQUIREMENTS | 11-52V DC, 4.4 mA |
| SWITCH | Flat, roll-off |
| WEIGHT | 253 g (8.9 oz) |
| DIMENSIONS | 0.91" (23.0 mm) H x 3.30" (83.9 mm) W x 4.25" (108.0 mm) D |
| OUTPUT CONNECTOR | Microphone: TB3M-type Cable: 3-pin XLRM-type |
| CABLE | 25.0' (7.6 m) long, 0.13" (3.2 mm) diameter, 2-conductor, shielded cable with TA3F and XLRM connectors |
| OPTIONAL INTERCHANGEABLE ELEMENTS | UE-H hypercardioid (100°) UE-O omnidirectional (360°) |
| ACCESSORY FURNISHED | Soft protective pouch |
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 20 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 11V to 52V DC phantom power source. It shall be capable of handling sound input levels up to 134 dB with a dynamic range of 108 dB. Nominal open-circuit output voltage shall be 19.9 mV at 1V, 1 Pascal. Output shall be low impedance balanced (50 ohms). It shall offer outstanding rejection of radio frequency interference (RFI).
The microphone shall incorporate self-contained electronics, eliminating the need for an external power module. A 7.6 m (25') miniature output cable with TA3F-type to XLRM-type connectors shall be supplied. The output of the microphone shall be a TB3M-type connector. The microphone shall include a switch to permit choice of flat response or 80 Hz low-frequency roll-off.
The microphone shall be equipped with an integral rotating output connector that allows the cable to exit from either the rear or the bottom of the microphone without the need to disassemble the microphone or use tools to change the cable exit location.
The microphone shall have a maximum width of 83.9 mm (3.30"), a maximum length of 108.0 mm (4.25") and a maximum height of 23.0 mm (0.91"). Weight shall be 253 grams (8.9 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 soft protective pouch.
The Audio-Technica U851Rb is specified.
