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CM-30
CM-30W
T
he Crown CM-30 is a professional-
quality,supercardioid condenser micro
phone designed for inconspicuous miking
of a choir, orchestra or stage. The mic cable
connects to the electronics/faceplate which fits
a standard electrical outlet box. The CM-30
also can hang over conference tables or dis-
cussion groups for inconspicuous isolated
miking.
Because of its supercardioid pickup pattern,
the CM-30 rejects background noise and room
reverberation, and improves gain-before-feed-
back, more than a microphone with a cardioid
pattern.
The CM-30 has a smooth, wide-range fre-
quency response for natural reproduction of
the singing voice, organ or other musical in-
struments. Extreme low frequencies are filtered
out to reduce pickup of room rumble.
The microphone output is balanced, low im-
pedance. It is protected against static and radio
frequency interference. A built-in removeable
hanger allows easy position adjustment by
bending the lower portion of the hanger. The
CM-30 requires 12-48V phantom power. The
CM-30 is black; the CM-30W is white.
Operating Instructions
The CM-30 consists of the microphone with
30' cable and associated electronics. The elec-
tronics PC board is mounted to the provided
rectangular electrical plate as shown in Fig. 4.
The mating electrical backbox should be in-
stalled at the mounting location. Input and out-
put screw terminals eliminate the need for
cable connectors. The provided strain relief
acts as a cable clamp when securely tightened.
A recommended microphone placement for
sound reinforcement is shown in Figs. 5a and
5b. For recording or broadcast, you might
want to place the microphone a few feet farther
away to pick up more room acoustics. Bend
the wire hanger to achieve the desired pickup
angle.
Architects' and Engineers' Specifications
The microphone shall be the Crown CM-30. It
shall be a professional-quality supercardioid
condenser microphone designed for incon-
spicuous miking of a choir or other large musi-
cal ensembles. It shall be hung from the
ceiling, where its cable shall connect to elec-
tronics installed in a standard electrical outlet
box.
Frequency response shall be 40 Hz to 20,000
Hz. Extreme low frequencies shall be filtered
out to reduce pickup of room rumble. Open-
MINIATURE SUPERCARDIOID
CONDENSER MICROPHONE
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. Recom-
mended 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 = 0.0002 dyne/cm
2
), A-weighted.
S/N Ratio: 66 dB at 94 dB SPL.
Maximum Sound Pressure Level: 120 dB SPL
produces 3% THD.
Input Connectors: Screw terminals.
Output Connectors: Screw terminals.
Operating Voltage: Phantom power, 12 to 48
volts DC, positive voltage on pins 2 and 3 with
respect to pin 1 of output terminal.
Materials: Brass housing, steel faceplate.
Finish: Black (CM-30) or white (CM-30W) micro-
phone, white faceplate.
Weight (microphone and cable): 4 ounces (113
grams).
Weight (microphone, cable and circuit): 7.5
ounces (212 grams).
Cable: Black (CM-30) or white (CM-30W), 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. 3 on reverse side.
Included Accessories: WS-5 windscreen (black
or white).
Optional Accessories:
Crown PH-1A phantom
power supply (1 channel, battery or AC adap-
tor powered), Crown PH-4B phantom power
supply (4 channels, AC powered).
*1 pascal = 10 dynes/cm
2
= 10 microbars = 94 dB SPL.
Fig. 1
Frequency Response
Frequency in Hz
Fig. 2
Polar Response
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