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. 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 Shure 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.
- 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
- 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
- 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