Shure SM81 Microphone Specification Sheet Specsheets En US

: Sm81 Specsheets En-Us SM81_specsheets_en-US 433830 s

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MODEL SM81

UNIDIRECTIONAL CONDENSER MICROPHONE

OVERVIEW

The Shure Model SM81 is a high-quality, unidirectional con-

denser 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, espe-

cially guitar, piano, and cymbals.

The SM81 is ruggedly constructed. It operates on phantom

power and performs over a wide range of temperatures and hu-

midity conditions. It is furnished with a swivel adapter, attenua-

tor-switch lock, foam windscreen, and case for carrying and stor-

age. Other accessories are available.

FEATURES

S20 Hz to 20 kHz frequency response

SFlat response curve for accurate reproduction of sound

sources

SLow noise and high output clipping level

SLow distortion over a wide range of load impedances

SCardioid polar pattern, uniform with frequency and symme-

tric about axis, providing maximum rejection and minimum

coloration of off-axis sounds

SLow RF susceptibility

SSelectable low-frequency response: flat, 6 or 18 dB/octave

rolloff

S0 dB/10 dB lockable attenuator switch

SPhantom powering (DIN 45 596 voltages of 12 to 48 Vdc)

SRugged steel construction for durability

SField-usable over wide range of temperature and humidity

conditions

SPECIFICATIONS

Type

Condenser (electret bias)

Frequency Response

20 to 20,000 Hz

20 200001000 10000

50 100 98765432 98765432

+10

0

–10

Hz

dB

1 METER

TYPICAL FREQUENCY RESPONSE

Polar Pattern

Cardioid (unidirectional) response—uniform with frequen-

cy, symmetrical about axis (see Figure NO TAG)

150o

120o

150o

120o

180o

30o

60o

90o

30o

60o

90o

–5 dB

–10 dB

–15 dB

–20 dB

0

500 kHz

100 Hz

1 kHz

150o

120o

150o

120o

180o

30o

60o

90o

30o

60o

90o

–5 dB

–10 dB

–15 dB

–20 dB

0

2 kHz

5 kHz

10 kHz

TYPICAL POLAR PATTERNS

Model Model SM81 Microphone

Specification Sheet

Specification Sheet

MODEL SM81 CONDENSER MICROPHONE

2

Output Impedance

Rated at 150 ohms (85 Ω actual)

Recommended minimum load impedance: 800 Ω (May be

used with loads as low as 150 Ω with reduced clipping

level)

Output Configuration and Connector

Balanced, transformer-coupled output; male XLR connec-

tor

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 Ω Load –4 dBV (0.63 V). . . . . . . . . . . . . . . . . . . . . . .

150 Ω Load –15 dBV (0.18 V). . . . . . . . . . . . . . . . . . . . . .

Total Harmonic Distortion

Less than 0.5% (131 dB SPL at 250 Hz into 800 Ω load)

Maximum SPL (at 1,000 Hz)

800 Ω load 136 dB (attenuator at 0). . . . . . . . . . . . . . . .

146 dB (attenuator at –10)

150 Ω 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 microphone output at 94 dB SPL

and microphone self-noise 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_ to 74_ C. . . . . . . . . . . . . . . . . . . . . . .

(–20_ to 165_ F)

Operating – 6.7_ to 49_ C. . . . . . . . . . . . . . . . . . . . . . (20_ to 120_ F)

Humidity:

Storage 0–95% relative humidity at room. . . . . . . .

temperature (72_to 80_ F, 22_ to 27_ C)

Case

Steel construction with vinyl metallic paint finish and stain-

less steel screens

Dimensions

See Figure NO TAG

Weight

Net 230 grams (8 oz). . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Packaged 740 grams (1 lb 10 oz). . . . . . . . . . . . . . . . . .

FURNISHED ACCESSORIES

Swivel Adapter A57F. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10 dB Attenuator Lock 34A830. . . . . . . . . . . . . . . . . . . . . . . . .

Carrying/Storage Case 65A1797. . . . . . . . . . . . . . . . . . . . . . .

Windscreen 49A111. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

REPLACEMENT PARTS

Cartridge and Grille Assembly R104. . . . . . . . . . . . . . . . . . .

OPTIONAL ACCESSORIES

Pop-Filter Grille A81G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Heavy-Duty Windscreen A81WS. . . . . . . . . . . . . . . . . . . . . . .

Tripod Microphone Stand (4.3 m [14 ft]) S15A. . . . . . . . . . . .

Stereo Microphone Adapter A27M. . . . . . . . . . . . . . . . . . . . . .

Cable (7.6m [25ft]) C25F. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Phantom Power Supply PS1A. . . . . . . . . . . . . . . . . . . . . . . . .