Crown Audio CM-30 - Manual

POLAR
PATTERN
MINIATURE SUPERCARDIOID
CONDENSER MICROPHONE
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 fi ts
a standard electrical outlet box. The CM-30 can
also hang over conference tables or discussion
groups for inconspicuous isolated miking.
Because of its supercardioid pickup pattern, the
CM-30 rejects background noise and room re-
verberation, and improves gain-before-feedback
more than a cardioid microphone.
The CM-30 has a smooth, wide-range
frequency response for natural reproduction of
the singing voice, organ or other musical instru-
ments. Extreme low frequencies are fi ltered out
to reduce pickup of room rumble.
The microphone output is balanced, low imped-
ance. It is protected against static and
radio frequency interference. A built-in remov-
able 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, at-
tached 30-ft (9.5-m) cable, and associated elec-
tronics. The electronics PC board is mounted
to the rectangular electrical plate (provided) as
shown in Fig. 4. The mating electrical backbox
should be installed at the mounting location.
Input and output screw terminals eliminate the
need for cable connectors. The provided strain
relief acts as a cable clamp when securely
tightened.
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’ Specifi cations
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 electronics
installed in a standard electrical outlet box.
Frequency response shall be 40 Hz to 20,000
Hz. Extreme low frequencies shall be fi ltered out
to reduce pickup of room rumble. Open-circuit
CM-30
CM-30W
Specifi cations
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 = 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.
Current drain: 4.5 milliamperes.
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-ft
(9.15-m) 2-conductor shielded 0.1-in. (0.254-
cm) diameter cable from microphone to electron-
ics; 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 adaptor
powered).
*1 pascal = 10 dynes/cm 2 = 10 microbars = 94 dB SPL.
Fig. 1
Frequency in Hz
Frequency Response
Fig. 2 Polar Response
Features
• Ideal for picking up choirs
• Supercardioid polar pattern aids gain-before-
feedback and rejects background noise
• Small and inconspicuous
• Hanger allows position adjustment
• Electronics mount in a standard electrical
outlet box