Download Print this page
Shure SM81 User Manual

Shure SM81 User Manual

Unidirectional condenser microphone
Hide thumbs Also See for SM81:

Advertisement

Quick Links

MODEL SM81
UNIDIRECTIONAL CONDENSER MICROPHONE
The Shure Model SM81 is a high-quality, unidirectional
condenser microphone designed for studio recording, broad-
casting, and sound reinforcement. Its wide frequency re-
sponse, low noise characteristics, and low RF susceptibility
have made it a standard for applications involving acoustic in-
struments, especially 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
storage. Other accessories are available.
Model SM81 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 symme-
tric 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
E2002, Shure Incorporated
27B2916 (BE)
Model SM81 User Guide
SPECIFICATIONS
Type
Condenser (electret bias)
Frequency Response
20 to 20,000 Hz (see Figure 1)
+10
0
–10
2
3
20
50
100
TYPICAL FREQUENCY RESPONSE
FIGURE 1
Polar Pattern
Cardioid (unidirectional) response—uniform with fre-
quency, symmetrical about axis (see Figure 2)
o
180
o
o
150
150
o
120
120
o
90
–20 dB
–15 dB
60
o
60
–10 dB
–5 dB
o
o
30
30
0
1 kHz
500 kHz
100 Hz
TYPICAL POLAR PATTERNS
FIGURE 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 clip-
ping level)
Output Configuration and Connector
Balanced, transformer-coupled output; male XLR con-
nector
Sensitivity (at 1,000 Hz)
Open Circuit Voltage
. . . . . . .
Clipping Level (at 1,000 Hz)
800 Ω Load
. . . . . . . . . . . . . . . . . . . . . .
150 Ω Load
. . . . . . . . . . . . . . . . . . . . . .
Total Harmonic Distortion
Less than 0.5% (131 dB SPL at 250 Hz into 800 Ω load)
1 METER
4
5
6
7
8
9
2
3
4
5
6
7
8
9
1000
20000
10000
Hz
o
180
o
o
150
150
o
o
120
o
o
90
90
–20 dB
–15 dB
o
o
60
–10 dB
–5 dB
o
o
30
30
0
2 kHz
5 kHz
10 kHz
–45 dBV/Pascal (5.6 mV)
(1 Pascal = 94 dB SPL)
–4 dBV (0.63 V)
–15 dBV (0.18 V)
Printed in U.S.A.
o
120
o
90
o
60

Advertisement

loading

Summary of Contents for Shure SM81

  • Page 1 FIGURE 1 struments, especially guitar, piano, and cymbals. Polar Pattern The SM81 is ruggedly constructed. It operates on phantom Cardioid (unidirectional) response—uniform with fre- power and performs over a wide range of temperatures and hu- quency, symmetrical about axis (see Figure 2) midity conditions.
  • Page 2 150 Ω, but a reduction in output clipping 80 Hz level will result. It should be noted that the power supply itself Attenuator Switch Positions (Lockable) may add loading (3300 Ω in the Shure PS1A power supply) to 0 or –10 dB the microphones. Power...
  • Page 3 Unscrew the grille and cartridge assembly sounds. To install the A81G, slip it over the SM81 until the inside by unscrewing counter-clockwise from the top. Turn the actua- of the A81G touches the top of the microphone.
  • Page 4 ....... . A81G A block diagram of the SM81 is shown in Figure 6. The ca- pacitor cartridge is followed by a switch-controlled capacitive Heavy-Duty Windscreen .