Crown CM-311A Quick Manual

CM-311A
CM-311AE
D
esigned for touring and live-sound applica-
tions, the Crown ® CM-311A is a rugged
head-worn microphone with unequalled
performance. It sounds like the best handheld
microphones—full, clear, and distortion-free, even
with the loudest singers.
The CM-311A is the latest version of the Crown's
proprietary Differoid ® technology. Its cardioid
pickup pattern rejects sounds from the rear, such as
floor monitors. Its noise-canceling ability rejects
sounds at a distance, such as instruments on stage
and crowd noise. This results in the CM-311A
having outstanding gain-before-feedback and
isolation.
Lightweight and comfortable, the mic's headband
and boom adjust to fit any singer. An included pop
filter greatly reduces breath noise and pops. Be-
cause of the boom's unique behind-the-ear design,
it does not cover up the singer's face.
Two models are available: CM-311A and CM-311AE.
The CM-311A is powered by a 9V battery or phan-
tom power. It has a battery belt pack with an on/off
switch, a programmable mic on/off switch, and a
"Mic On" LED. The CM-311AE is a pig-tail version
allowing you to connect it to the wireless transmit-
ter of your choice.
NOTE: Putting an XLR connector on the CM-311AE
and connecting to a mic input with phantom power
WILL damage the mic element. For wired applica-
tions, use the CM-311A.
How to adjust for best fit and to prevent boom
bounce
Note: To get the maximum performance out of this
microphone, take the time to adjust it to fit cor-
rectly.
For best results, the CM-311A MUST be custom
fitted to a single user's head. This simple procedure
takes only a few minutes. Please refer to Fig. 5 and
locate the parts described.
1. If the microphone is for yourself, we suggest that
you use a mirror to double check the fit as you
make adjustments.
2. Loosen (just a little) the thumbscrew located on
the outside of the foam block, part way back on the
boom. This allows the boom to slide in and out, and
to rotate left and right.
3. Now bend the headband wire to fit your head. Put
the foam-block wire behind your ear. Then you can
bend the earpieces to fit snugly around your ears.
The back of the headband should fit firmly against
the back of your neck.
POLAR
PATTERN
DIFFEROID HEAD-WORN
CONDENSER MICROPHONE
Specifications
Transducer type: Electret condenser.
Frequency response (typical): 50 Hz to 17,000 Hz
(see Fig. 1).
Polar pattern: Cardioid (see Fig. 2).
Impedance: CM-311A, 75 ohms balanced. CM-
311AE, 6 kilohms unbalanced.
Recommended load impedance: CM-311A, 1000
ohms or greater. CM-311AE, 10 kilohms.
Open-circuit sensitivity, typical, close-talking: CM-
311A, 4 mV/Pa* (–48 dB re 1V/Pa), CM-311AE,
1.25 mV/Pa (–58 dB re 1V/Pa).
Power sensitivity, typical, close-talking: CM-
311A: –42.5 dB re 1 mW/Pa*, CM-311AE: –71.5
dB re 1 mW/Pa.
Equivalent noise level (self noise): 26 dB SPL
typical (0 dB = 0.0002 dyne/cm
S/N ratio: 68 dB at 94 dB SPL.
Maximum SPL: CM-311A, 148 dB SPL produces 3%
THD. CM-311AE, 140 dB SPL with 3V DC, 148 dB
SPL with 9V DC.
Operating voltage: CM-311A, 9V DC internal
alkaline battery or 18-48V phantom power. CM-
311AE, 3–9V DC from the transmitter's battery.
Polarity: Positive pressure on diaphragm produces
positive voltage on CM-311A XLR pin 2 with
respect to pin 3, and on CM-311AE shield with
respect to white lead.
Current drain: CM-311A, 6.5 mA nominal.
CM-311AE, 0.27 mA nominal.
Battery life: CM-311A, 85 hours. CM-311AE,
approximately equal to transmitter battery life.
Off-attenuation: 70 dB.
Output connectors: CM-311A, 3-pin pro audio (XLR
type). CM-311AE, supply your own to match your
transmitter.
Cables (CM-311A): 2-conductor shielded,
unbalanced cable, 42-inches (106.68 cm) from
headband to battery pack. Use 2-conductor
shielded mic cable (not included) between XLR
connector and mixer mic input.
Cable (CM-311AE): In-line with this cable is a small
circuit module that equalizes the microphone
signal. Cable is 42-inches (106.68 cm) long from
headband to module, 12-inches (30.48 cm) from
module to cable end. 2-conductor shielded
unbalanced cable, unterminated.
Materials: High-impact plastic mic housing, brass
boom, steel wire headband, high-impact plastic
and steel battery pack.
Finish: Satin black.
Net weight: Head-worn mic, 2.1 oz (61 g). CM-311A
belt pack and battery, 6.1 oz (173g).
Dimensions: Headband 5.5-in. (13.97 cm) diameter,
adjustable. Boom approximately 7 in. (17.78 cm)
x 3 in. (7.62 cm). See Figs. 3 and 4.
Included accessories: Microphone carrying case,
WS-6 foam pop filter, clothing clip.
CM-311A
Optional accessories: PH-4B phantom power
supply (4 channels, AC powered). PH-1A
phantom power supply (1 channel, battery or AC-
CM-311AE
adapter powered). WS-14 accessory windscreen.
*1 pascal = 10 dynes/cm
Fig. 1
+15
+10
+5
dB 0
-5
-10
-15
-20
-25
-30
-35
20
2 ), A-weighted.
Fig. 2
Fig. 3
2 = 10 microbars = 94 dB SPL.
Frequency Response
0˚, 1.375"
0˚ 2'
120˚, 2'
100 1K 10K 20K
Frequency in Hz
Polar Response
MIC