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SM81 Instrument Microphone |
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Product Code: SM81
Instrument Microphone
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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. |
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| 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
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| Specifications |
- Type : Condenser (electret
bias)
- 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 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 (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.
- 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)
Humidity:
Storage 0 to 95% relative humidity at room temperature (72 degrees
to 80 degrees F, 22 degrees to 27 degrees
- Case : Steel construction with
vinyl metallic paint finish and stainless steel
screens
- Dimensions : See User
Guide
- Weight
Net: 230 grams (8 oz)
Packaged: 740 grams (1 lb 10 oz)
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