Product Description

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.

Amazon.com

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.

Key Features

• 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