Shure SM81

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.

SM81-LC - With windscreen, no cable. Phantom power required.

Features
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. Other accessories are available.
•	20 Hz to 20 kHz frequency response
•	Flat response curve for accurate reproduction of sound sources
•	Low noise and high output clipping level
•	Low distortion over a wide range of load impedances
•	Cardioid polar pattern, uniform with frequency and symmetric about axis, providing maximum rejection and minimum coloration of off-axis sounds
•	Low RF susceptibility
•	Selectable low-frequency response: flat, 6 or 18 dB/octave rolloff
•	0 dB/10 dB lockable attenuator switch
•	Phantom powering (DIN 45 596 voltages of 12 to 48 Vdc)
•	Rugged steel construction for durability
•	Field-usable over wide range of temperature and humidity conditions

Specifications
Type	Condenser (electret bias)
Frequency Response	20 to 20,000 Hz
Polar Pattern	Cardioid (unidirectional) response-uniform with frequency, symmetrical about axis
Output Impedance	Rated at 150 ohms (85 ohms actual)
Recommended minimum load impedance: 800 ohms (May be used with loads as low as 150 ohms with reduced clipping level)
Output Configuration and Connector	Balanced, transformer-coupled output; male XLR connector
Sensitivity (at 1,000 Hz)	Open Circuit Voltage: -45 dBV/Pascal (5.6 mV (1 Pascal = 94 dB SPL)
Clipping Level (at 1,000 Hz)	800 ohm Load: -4 dBV (0.63 V)
Clipping Level (at 1,000 Hz)	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)
Maximum SPL (at 1,000 Hz)	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 (equivalent sound pressure levels; measured with true rms voltmeter)	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 *S/N ratio is difference between 94 dB SPL and product's equivalent self noise (SPL A-weighted).
Overvoltage and Reverse Polarity Protection	Max. external voltage applied to pins 2 and 3 with respect to pin 1: +52 Vdc
Overvoltage and Reverse Polarity Protection	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
Power	Current Drain: 1.2 mA max.
Environmental Conditions	Temperature: Storage: -29 degrees to 74 degrees C (-20 degrees to 165 degrees F) Operating: -6.7 degrees to 49 degrees C (20 degrees to 120 degrees F)
Environmental Conditions	Humidity: Storage 0 to 95% relative humidity at room temperature (72 degrees to 80 degrees F, 22 degrees to 27 degrees C)
Case	Steel construction with vinyl metallic paint finish and stainless steel screens
Dimensions	See User Guide
Weight	Net: 230 grams (8 oz)
Weight	Packaged: 740 grams (1 lb 10 oz)

Brochure

User Guide