SM81-LC Cardioid Condenser Instrument Microphone

The 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.
POWER REQUIREMENTS NOTE: This microphone requires phantom power and performs best with a 48 Vdc supply (IEC-61938). However, it will operate with slightly decreased headroom and sensitivity with supplies as low as 11 Vdc. Most modern mixers provide phantom power. You must use a balanced microphone cable: XLR-to-XLR or XLR-to-TRS. Built to withstand the rigors of regular stage and studio use, the SM81 unidirectional condenser microphone is a great choice for studio recording, broadcasting, and sound reinforcement. Its wide frequency response, low noise characteristics, and low RF susceptibility make it a perfect match for applications involving acoustic instruments, especially guitar, piano, and cymbals. Ruggedly constructed, the SM81 operates on phantom power and performs over a wide range of temperatures and humidity conditions. It comes with a swivel adapter, attenuator-switch lock, foam windscreen, and case for carrying and storage. Key Features Frequency response. Polar pattern. 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); 150 ohm
Load: -15 dBV ( 0.18 V) Total Harmonic Distortion Less than 0.5 % (131 dB SPL at 250
H: z 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 (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 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.
Case: Steel construction with vinyl metallic paint finish and stainless steel screens
Weight: 8 ounces