Shure SM27, Manual

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GENERAL DESCRIPTION
The Shure
®
SM27 is a rugged and versatile large-diaphragm, side-address car-
dioid microphone. Low self-noise and extended frequency response picks up vocal
and instrument nuances with clarity. Durable Shure construction features three
separate mesh layers that reduce wind and breath noise. Equally comfortable on
the stage or in the studio.
FEATURES
Cardioid polar pattern—the most commonly used pattern for both studio and •
live applications
1 inch, externally biased, ultra-thin, 2.5 μm, 24 Karat gold-layered, low mass, •
Mylar
®
diaphragm provides superior transient response
Class A, discrete, transformerless preamplifier for transparency, extremely fast •
transient response and no crossover distortion, while minimizing harmonic and
intermodulation distortions
Premium electronic components and gold-plated internal and external
•
connectors
Subsonic filter eliminates rumble from mechanical vibration below 17 Hz
•
Switchable 15 dB pad for handling extremely high sound pressure levels (SPLs) •
3-position switchable low-frequency filter helps reduce unwanted background •
noise or counteract proximity effect
Integrated three-stage “pop” protection grille reduces plosives and other breath
•
noise
Internal shock mount reduces handling and stand noise
•
PERFORMANCE CHARACTERISTICS
Extended frequency response •
Low self-noise •
Exceptional low-frequency reproduction •
Can withstand high sound pressure levels (SPLs) •
High output level •
No crossover distortion •
Uniform polar response •
Superior common mode rejection and suppression of radio frequency •
interference (RFI)
APPLICATIONS
Voice and vocals •
Electric guitar amplifiers •
Brass and woodwind instruments •
Orchestras, choirs, and wind ensembles •
Overhead miking of drums and percussion instruments •
Close-miking of acoustic instruments such as piano, guitar, violins, drums, and •
percussion
Low-frequency instruments such as double bass and kick drum
•
Room ambience pick-up (guitar amplifier or drums) •
Note: Sound quality is strongly affected by microphone location and room acous-
tics. To achieve the best overall sound for a particular application, it may be neces-
sary to experiment with microphone placement and room treatments.
Mounting the Microphone
Thread the supplied stand adapter onto a floor or boom stand, then thread the
microphone onto the adapter.
NOTE: Since this microphone reproduces ultra-low frequencies, use an isolating
shock mount (available at www.shure.com) to reduce low-frequency mechanical
vibrations transmitted through the stand.
Positioning the Microphone
The front of the microphone is marked by the Shure logo. Position this side toward
the sound source.
Selecting Low-Frequency Response
A three-position switch on the back of the microphone lets you adjust the low-fre-
quency response. Use the low-frequency filter to reduce wind noise, room noise,
or proximity effect.
Flat response. Provides the most natural sound in most applications.
Low frequency cutoff. Provides an 18 dB-per-octave cutoff at 80 Hz. Helps
eliminate floor rumble and low-frequency room noise from heating and air condi-
tioning systems. This setting may also be used to compensate for proximity effect
or to reduce low frequencies that make an instrument sound dull or muddy.
Low frequency rolloff. Provides a 6 dB-per-octave rolloff filter at 115 Hz.
Use this to compensate for proximity effect or to reduce low frequencies that could
make an instrument sound dull or muddy.
Setting Attenuation
The attenuation switch lets you reduce the signal level without altering the fre-
quency response. This can prevent extremely loud sounds from overloading the
microphone.
0 dB For “quiet” to “normal” sound levels.
-15 dB For use with extremely loud sound sources such as drums, horns, or loud
guitar cabinets.
Integral Pop Filter
The microphone grille consists of 3 separate mesh layers that act as an integral
pop filter. This helps reduce wind and breath noise. Depending on the performer,
an external pop-protection screen or windscreen may be necessary when close-
miking vocalists.
Load Impedance
Maximum SPL capability, output clipping level, and dynamic range varies with the
input load impedance of the preamplifier to which you connect the microphone.
Shure recommends a minimum input load impedance of 1000 Ω, and most modern
microphone preamplifiers meet this requirement. Higher impedance results in bet-
ter performance for these specifications.
Power Requirements
This microphone requires phantom power and performs best with a 48 Vdc supply
(IEC-268-15/DIN 45 596). However, it will operate with slightly decreased head -
room and sensitivity with supplies as low as 11 Vdc. Most modern mixers provide
phantom power. Phantom power can only be transmitted through a cable termi-
nated with XLR connectors at each end.