Shure SM81 Specification Sheet

Product Speciﬁcations

SM81 Cardioid Condenser Microphone

Overview

The legendary SM81 is an industry-standard, flat-response cardioid condenser microphone, featuring a wide frequency response and low self-noise. Highly versatile, the SM81’s renowned sonic accuracy is a constant choice around the world for acoustic stage and studio performance, including guitar, piano and drum overhead applications.

Features

• 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

Available Models

SM81-LC Includes Stand Adapter and Zippered Pouch

Specifications

Type Condenser

Frequency Response 20 to 20,000 Hz

Polar Pattern Cardioid

Sensitivity (at 1,000 Hz) Open Circuit Voltage: -45 dBV/Pascal (5.6 mV) (1 Pa = 94 dB SPL)

Impedance

Output Clipping Level

Maximum SPL (at 1,000 Hz)

Self-Noise 16 dB typical, A-weighted

Hum Pickup -3 dB equivalent SPL in a 1 mOe field (60 Hz)

Signal-to-Noise Ratio

Overvoltage and Reverse Polarity Protection

Polarity Positive pressure on diaphragm produces positive voltage on pin 2 relative to pin 3

Power 11 to 52 vdc, 1.2 mA

Case Steel construction with vinyl metallic paint finish and stainless steel screens

Connector Three-pin professional audio connector (male XLR type)

Net Weight 230 grams (8 oz)

Dimensions 212 mm (7-9/16 in.) L x 23.5 mm (2 in.) W at the widest point

Rated at 150 ohms (85 ohms actual)

Recommended minimum load impedance: 800 ohms

800 ohm Load: -4 dBV (0.63 V) 150 ohm Load: -15 dBV (0.18 V)

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)

19 dB typical, weighted per DIN 45 405

78 dB (IEC 651)* at 94 dB SPL

S/N ratio is difference between 94 dB SPL and equivalent SPL of self– noise A-weighted

Max. external voltage applied to pins 2 and 3 with respect to pin 1: +52 Vdc Reverse polarity protection: 200 mA max. (diode-clamped)

SM81

Optional Accessories and Replacement Parts

A57F Microphone Clip A81G Grille and Windscreen A81WS Large Foam Windscreen

Polar pattern

100 Hz 500 Hz 1000 Hz

2000 Hz 5000 Hz 10000 Hz

Frequency response

+20

+10

1 Meter

–10

–20

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