CROWN CM311A Details
The CM Series of
condenser microphones by Crown offer exceptional quality at truly affordable
prices. With application-specific microphones, ranging from professional-grade
headworn microphones to critical-response microphones for the most demanding
recording applications, the CM Series can fit most any microphone need. Types
include hand-held, headworn, hanging, or stand-mounted.
With innovations
such as Crown’s patented Differoid® technology,
the CM series combines years of technical know-how with durable, high-quality
materials and workmanship. These qualities are direct contributors to the
successful performances of our customers, and a primary reason for the success
Crown enjoys today.
Used by world-renowned artists such as Garth Brooks, Britney
Spears and Janet Jackson, the Crown CM-311A Differoid microphone is the headworn
microphone of choice for the live-performance industry. Featuring clear,
crisp vocal performance in a lightweight package, this microphone signifies
the quality and performance value of the Crown CM Series of microphones.
Designed for touring
and live-sound applications, 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. Because
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 phantom
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 transmitter
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 applications,
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 correctly.
For best results, the CM-311A MUST be custom
fitted to a single user’s head. This simple procedure
takes only a few minutes.
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.
Specifications
Transducer type: Electret condenser.
Frequency response (typical): 50 Hz to 17,000 Hz
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/cm2), A-weighted.
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).
CM-311A
CM-311AE
Dimensions: Headband 5.5-in. (13.97 cm) diameter,
adjustable. Boom approximately 7 in. (17.78 cm)
x 3 in. (7.62 cm).
Included accessories: Microphone carrying case,
WS-6 foam pop filter, clothing clip.
Optional accessories: PH-4B phantom power
supply (4 channels, AC powered). PH-1A
phantom power supply (1 channel, battery or ACadapter
powered). WS-14 accessory windscreen.
*1 pascal = 10 dynes/cm2 = 10 microbars = 94 dB SPL.
Model CM-311A shall include a battery belt pack.
Model CM-311AE shall be the head-worn microphone
alone. In the CM-311A, a 42-inch, permanently
attached, two-conductor shielded cable shallconnect the microphone to the belt
pack. The belt
pack shall include a 3-pin pro audio (XLR type)
connector. In the CM-311AE, a 42-inch, permanently
attached, two-conductor shielded cable can be
connected to a transmitter.
Model CM-311A shall be powered by a 9V battery in
the belt pack, or by 18 to 48V phantom power. The
belt pack shall have a battery on/off switch, a programmable
mic on/off switch, and a “Mic On” LED.
Model CM-311AE shall be powered by 3–9V DC from
a transmitter.
Nominal open-circuit sensitivity shall be 4 or 1.25
mV/Pa. Maximum SPL shall be 148 dB SPL for 3%
THD. Equivalent noise shall be 27 dBA nominal.
Frequency response shall be 50 Hz to 17,000 Hz
with a uniform off-axis response, over 20 dB down
at the rear null. The Crown models CM-311A and
CM-311AE are specified.
CROWN CM311A HEADSET MIC
