| Transducer Type |
Condenser |
|
The Shure SM81 is a high-quality, unidirectional condenser microphone designed for studio recording, broadcasting, and sound reinforcement. Its wide frequency response, low noise characteristics, and low RF susceptibility have made it a standard for applications involving acoustic instruments, especially guitar, piano, and cymbals.
The SM81 is ruggedly constructed. It operates on phantom power and performs over a wide range of temperatures and humidity conditions. It is furnished with a swivel adapter, attenuator-switch lock, foam windscreen, and case for carrying and storage.
|
| Polar pattern |
Cardioid |
| Frequency response |
20hz to 20kHz |
| Impedance |
150 ohms (85 ohms actual) for connection to microphone inputs rated low Z |
| Output Level (at 1,000 Hz) |
Open Circuit Voltage: -45 dBV/Pa* (5.6 mV)*1 Pa = 94 dB SPL |
| Output Configuration and Connector |
Balanced, transformer-coupled output; male XLR connector |
| Clipping Level (at 1,000 Hz) |
800 ohm Load: -4 dBV (0.63 V)
150 ohm Load: -15 dBV (0.18 V) |
| Total Harmonic Distortion |
Less than 0.5% (131 dB SPL at 250 Hz into 800 ohm load) |
| Maximum SPL (at 1,000 Hz) |
800 ohm load: 136 dB (attenuator at 0) 146 dB (attenuator at -10)
150 ohm load: 128 dB (attenuator at 0) 138 dB (attenuator at -10) |
| Hum Pickup |
-3 dB equivalent SPL in a 1 mOe field (60 Hz) |
| Self-Noise |
16 dB typical, A-weighted
19 dB typical, weighted per DIN 45 405 |
| Signal-to-Noise Ratio |
78 dB (IEC 651)* at 94 dB SPL |
| Overvoltage and Reverse Polarity Protection |
Max. external voltage applied to pins 2 and 3 with respect to pin 1: +52 Vdc
Reverse polarity protection: 200 mA max. (diode-clamped) |
| Polarity |
Positive pressure on diaphragm produces positive voltage on pin 2 relative to pin 3 |
| Cartridge Capacitance |
54 pF |
| Low Frequency Response Switch Positions |
Flat; -6 dB/octave below 100 Hz; -18 dB/octave below 80 Hz |
| Attenuator Switch Positions (Lockable) |
0 or -10 dB |
| Power |
Supply Voltage: 11 to 52 Vdc, positive, pins 2 and 3
Current Drain: 1.2 mA max. |
| Environmental Conditions |
Temperature:
Storage: -29° to 74° C (-20° to 165° F)
Operating: -6.7° to 49° C (20° to 120° F)
Humidity:
Storage 0 to 95% relative humidity at room temperature (72° to 80° F, 22° to 27° C) |
| Dimensions |
212mm x 23.5mm x 20mm |
| Weight |
230g (8oz.) |
