Crown CM-31 User manual

Crown International, Inc.
P.O.Box 1000
Elkhart, IN 46515-1000
TEL: [phone]
FAX: [phone]FAX
@crown®
CM-31
CM-31W
©1997 Crown International, Inc.
Specificationssubject tochange withoutprior notice.
Crown®isa registered trademarkof CrownInterna-
tional,Inc.
10/97 125114-1
condensermicrophonedesignedforinconspicu-
ous miking of a choir or other large musical
ensembles. It can be hung from the ceiling,
where its cable shall connect to a cylindrical
electronics power module that adapts the micro-
phone for phantom powering.
Frequency response shall be 40 Hz to 20,000 Hz.
Extreme low frequencies shall be filtered out to
reduce pickup of room rumble. The power mod-
ule shall have flat/low-cut switch. Open-circuit
sensitivity shall be 10 mV/Pa. Equivalent noise
level shall be 28 dBA SPL typical; SPL for 3%
THD shall be 120 dB. The microphone output
shall be balanced, low impedance, with RFI and
staticprotection.
A built-in removable hanger shall allow position
adjustment. The mic-cable connector shall be a
TB3F. The power module input connector shall be
a TB3M and the power module output connector
shall be a 3-pin pro audio XLR-type. Operating
voltage shall be standard phantom power, 12 to
48 volts DC, positive voltage on pins 2 and 3 with
respect to pin 1 of output connector. Finish shall
be black (CM-31) or white (CM-31W). The cable
from mic to electronics shall be 30' 2-conductor
shielded. The Crown CM-31 is specified.
Warranty
Crownprofessionalmicrophones are guaranteed
unconditionallyagainstmalfunctionfromany
cause for a period of three years from date of
original purchase. See enclosed warranty sheet
for additional information.
Service
If the microphone does not function properly,
verify that it is placed correctly and is connected
as described in the Operating Instructions. Also
check mic cables and your power supply. If
service is required, return the microphone in it’s
original packaging to the Crown Service Depart-
ment, Plant 2 SW, 1718 W. Mishawaka Road,
Elkhart, IN 46517. For further assistance or
technical support call 800-342-6939.
Fig. 4b
Fig. 4a
Fig. 5
CM-31/CM-31W Schematic
Fig. 6
Use the clamp and screw provided to mount the
CM-31/CM-31W power module onto the ceiling,
a wooden beam, or beneath a lectern/table.
Fig. 7

CM-31
CM-31W
MINIATURECONDENSER
HANGINGMICROPHONE
The Crown CM-31 is a professional-
quality, supercardioidcondenser micro-
phonedesignedforinconspicuousmiking
of a choir, orchestra or stage. It also can hang
over conference tables or discussion groups for
inconspicuousisolatedmiking.
The CM-31 consists of two parts: the micro-
phone with a permanently attached 30' cable and
thecylindrical electronics powermodule.
The mic cable connects to the power module
which adapts the microphone for phantom
powering and includes a low-cut switch. Cable
connection is via miniature 3-pin connectors. The
power module output is balanced, low imped-
ance. It is protected against static and
radio-frequencyinterference.
The CM-31 has a smooth, wide-range frequency
response for natural reproduction of the singing
voice, organ or other musical instruments.
Extreme low frequencies are filtered out to reduce
pickup of room rumble.
The microphone has a built-in removable hanger
whichallows easy positionadjustment.The
CM-31 microphone and cable are black; the
CM-31W microphone and cable are white.
Operating Instructions
The power module supplied has been matched to
the microphone. For best performance do not
intermix microphones and modules.
Plug the microphone into the electronics power
module. Run a 2-conductor shielded mic cable
(not supplied) from your mixer to the power
module, and plug it in.
Experiment with microphone placement before
permanently installing the power module. A
suggested placement for choir sound reinforce-
ment is shown in Figs. 4a and 4b. For recording
or broadcast, you might want to place the micro-
phone a few feet farther away to pick up more
room acoustics. Bend the wire hanger to achieve
the desired pickup angle.
If rumble from trucks or air-conditioning is
excessive, switch in the low-cut filter on the
power module. The low-cut position ( ) is
toward the microphone.
After finding the desired microphone position,
install the power module in one of three ways:
• Install the power module in the ceiling (Fig. 6).
Pull up the mic cable until the mic is at the
desired height, then knot the cable.
• Clamp the power module to a beam overhead
(Fig. 7).
• Tape the power module to the floor
Architects’ and Engineers’ Specifications
The microphone shall be the Crown CM-31. It
shallbe aprofessional-qualitysupercardioid
Specifications
Type: Unidirectional condenser.
Transducer: Electret condenser.
Frequency Response (typical): 40 Hz to 20,000 Hz
(see Fig. 1).
Polar Pattern: Supercardioid (see Fig. 2).
Impedance: 150 ohms, balanced. Recommended
minimum load impedance 1000 ohms.
Open Circuit Sensitivity: 10 mV/Pa* (–40 dB re 1
volt/Pa).
Power Sensitivity: –37.5 dB re 1 mW/Pa.
Equivalent Noise Level: 28 dB SPL typical (0 dB =
.0002 dyne/cm2), A-weighted.
S/N Ratio: 66 dB at 94 dB SPL.
Maximum Sound Pressure Level: 120 dB SPL
produces 3% THD.
Mic-Cable Connector: TB3F (mini XLR-type).
Power module Connector (input): TB3M (mini XLR-
type). See Fig. 3.
Power module Connector (output): 3-pin pro audio
XLR-type.
Power Module Switch: Flat/low-cut.
Operating Voltage: Phantom power, 12 to 48 volts
DC, positive voltage on pins 2 and 3 with respect
to pin 1 of output connector.
Materials: Brass housing, steel power module
housing.
Finish: Black (CM-31) or white (CM-31W).
Weight (microphone and cable): 4 ounces (113
grams).
Weight (microphone, cable and power module):
9.5 ounces (269 grams).
Cable: Black (CM-31) or white (CM-31W), 30' 2-
conductor shielded 0.1" diameter cable from
microphone to electronics; none supplied for
electronics output. Use 2-conductor shielded
microphone cable.
Dimensions: See Fig. 5 on reverse side.
Included Accessories: WS5 black foam
windscreen for CM-31, WS5W white foam
windscreen for CM-31W.
Optional Accessories: Crown PH-1A phantom
power supply (1 channel, battery or AC adaptor
powered), Crown PH-4B phantom power supply
(4 channels, AC powered).
*1 pascal = 10 dynes/cm2= 10 microbars = 94 dB SPL.
Fig. 1
FrequencyinHz
Frequency Response
Fig. 2 Polar Response
Fig. 3