Page 1
POLAR
PATTERN
CM-312AHS
he Crown® CM-312AHS is a rugged, light
weight headworn microphone that mounts on
T
a Sony MDR-7506 or MDR-V6 headphone.
Some applications are radio and TV sports broadcasts, and radio studio announcing.
Because the microphone is to the side of the mouth,
the mic looks inconspicuous and does not pick up
breath pops. The sound of the CM-312AHS can be
tailored to taste by moving the microphone closer or
farther from the corner of the mouth.
The CM-312AHS sounds like the best handheld
microphones. Its hypercardioid pickup pattern
reduces feedback and aids isolation. In difficult
situations, the Crown CM-311AHS headworn mic is
recommended because it picks up even less feedback
and leakage than the CM-312AHS.
The microphone adjusts to fit any user. It mounts
securely on either earpiece of the popular Sony MDR7506 or MDR-V6 headphone. An included foam pop
filter reduces breath pops and wind noise.
Supplied with the microphone is a belt pack. It
includes an XLR-type output connector, a battery on/
off switch, a programmable mic on/off switch, and a
“Mic On” LED. The microphone is an electretcondenser type, powered by phantom power or by
the 9V battery in the belt pack.
How to mount the mic on the Sony headphone
Please see Fig. 3. As supplied from the factory, the
microphone is ready to mount on the right earpiece
of the Sony headphone. If you want to do this, slip
the mount over the yoke above the right earpiece and
tighten the screws. You may want to route the mic
cable along the headband and along the headphone’s
coiled cable.
If you want to mount the microphone on the left
earpiece, please refer to Fig. 4 and follow this procedure:
1. Remove thumbscrew that holds boom in block.
2. Pull block off pin.
3. Slide block outer half off to the right.
4. Reverse boom direction; place boom in block
inner half.
5. Slide block outer half on from the right.
6. Insert pin into block.
7. Insert thumbscrew and tighten it.
8. Attach mount to left earpiece yoke.
How to adjust for fit
The CM-312AHS can be adjusted to fit any user.
Please refer to Fig. 3 and follow these steps:
1. Loosen the thumbscrew so the boom moves
freely.
2. Put on the Sony headphones with the microphone attached.
3. You can move the microphone toward and away
from your mouth, and also left, right, up and down.
Position the mic to the side of your mouth, about 1"
in front (Fig. 5).
HYPERCARDIOID CONDENSER MICROPOHONE
FOR USE WITH SONY MDR-7506 AND MDR-V6
HEADPHONES
Specifications
Transducer type: Electret condenser.
Frequency response (typical): 50 Hz to 17 kHz (see Fig.
1).
Polar pattern: Hypercardioid. See Fig. 2.
Impedance: 75 ohms balanced.
Recommended load impedance: 1000 ohms
minimum.
Open-circuit sensitivity, typical, close-talking: 4 mV/
Pa* (-48 dB re 1 V/Pa*).
Power sensitivity, typical, close-talking: -42.7 dB
re 1 mW/Pa.
Equivalent noise level (self-noise): 31 dB SPL typical
(0 dB=.0002 dyne/cm
S/N ratio: 63 dB at 94 dB SPL.
Maximum SPL: With phantom power, 148 dB SPL
produces 3% THD. With battery power, 146 dB SPL
produces 3% THD.
Operating voltage: 9V DC internal alkaline battery (not
supplied) or 18-48V phantom power.
Polarity: Positive pressure on diaphragm produces
positive voltage on pin 2 with respect to pin 3 of
output connector.
Current drain: 5 mA.
Battery life: 110 hours.
Output connector: 3-pin pro audio (XLR type).
Cables: 2-conductor shielded, unbalanced cable, 4 feet
from mic capsule to battery pack. Use 2-conductor
shielded mic cable (not included) between XLR-type
connector and mixer mic input.
Materials: High-impact plastic and PVC mic housing,
brass boom, steel wire headband, high-impact plastic
mount, high-impact plastic and steel battery pack.
Finish: Satin black.
Net weight: Headworn mic 1.8 oz. (50.3 g). Belt pack
and battery, 6.1 oz. (173g).
Dimensions: Mount 3" diameter. Boom approximately
5.75". See Figs. 6 and 7.
Included accessories: Microphone carrying case and
WS-7 foam pop filter.
Optional accessories: PH-4B phantom power supply
(4 channels, AC powered). PH-1A phantom power
supply (1 channel, battery or AC/DC adapter
powered)
.
*1 pascal = 10 dynes/cm2 = 10 microbars = 94 dB SPL.
2
), A-weighted.
Fig. 1
+15
+10
+5
dB 0
-5
-10
-15
-20
-25
-30
-35
20 100
Fig. 2
300˚
270˚
240˚
Fig. 3
MOUNT
TO MOVE MIC
IN OR OUT
Fig. 4
BLOCK
INNER HALF
BLOCK
Frequency Response
0˚, 1.375"
0˚ 2'
120˚, 2'
Frequency in Hz
Polar Response
330˚
FRONT
REAR
210˚
DETAIL
TO MOVE MIC
UP OR DOWN
TO MOVE MIC
LEFT OR RIGHT
THUMBSCREW
0˚
-0
-5
-10
-15
-20
1K
THUMBSCREW
BOOM
30˚
150˚180˚
YOKE
MIC
10K
1000 Hz
300 Hz
6000 Hz
PIN
BLOCK
OUTER HALF
20K
60˚
90˚
120˚
Page 2
Changing the mic position changes the ratio of lows
(
)
(
)
(
)
to highs. Adjust the position for the sound you
prefer.
If you hear breath pops when using the mic, it is too
close to your mouth. Loosen the thumbscrew and
move the mic farther to the side of your mouth until
you no longer hear pops. Since the mic is very “hot”,
the level loss should not be a problem.
If the mic sounds nasal or pinched, it is too close to
your mouth, and is not picking up sounds from your
nose. Loosen the thumbscrew and move the mic
farther to the side of your mouth until it sounds
natural (Fig. 5). Or angle the mic to aim more toward
your nose.
4. Tighten the thumbscrew.
Fig. 5
Typical mic position at one
side of the mouth. If you hear
breath pops or a nasal sound,
move mic sideways away from
mouth.
Fig. 6
Dimensions
3"
Operation
1. Access the battery by sliding open the battery
cover.
2. Insert a fresh 9V alkaline battery (Mallory Duracell
MN9100 or equivalent) into the battery tray. The
battery cover shows the correct polarity.
3. Replace the battery cover.
Connect the belt pack to the mixer using a 2-conductor shielded mic cable with XLR-type connectors. If
your mixer lacks phantom power, either turn on the
battery switch on the belt pack, or use a separate
phantom-power supply (such as the Crown PH-1A or
PH-4B).
If you’re using phantom power and the battery
switch is on, the battery will automatically take over if
phantom power fails. Turn off the battery switch
when not in use to prolong battery life.
After 110 hours of use, or if the sound is distorted,
it’s time to replace the battery.
The mic is not shock mounted because a shock
mount would add undesirable size and weight. If you
clip the cable to your clothing to prevent cable
rubbing, you should hear no handling noise.
If the mic is too “hot” or sensitive, you can reduce its
output level by adding a resistor across output
connector pins 2 and 3. Use 200 ohms for 6 dB
loss. Use 65 ohms for 12 dB loss.
How to program the mic on/off switch
The mic on/off switch can be programmed to work in
three ways:
Push-on/push-off (as supplied).
Momentary on (push to talk).
Momentary off (cough button).
To change the switch operation, open the belt-pack case
by removing the three screws. Set the switch as shown
below:
TO XLR
CM-312AHS
Warranty
Crown professional microphones are guaranteed
against malfunction for a period of three years from
date of original purchase. Please refer to the enclosed
full warranty statement for more detail.
Service
If the microphone does not function properly, check
that it is aimed correctly and is connected as described in this data sheet. If the microphone is
defective, return it in the original packaging to Crown
Factory Service, 1718 West Mishawaka Road, Elkhart,
IN 46517. For further assistance or technical support
call 800-342-6939.
Fig.7
(2.7 cm)
1.062"
5.75"
Dimensions
2.593"
6.6 cm
3.745"
(9.5 cm)
2"
.680"
(1.7 cm)
PUSH ON/
PUSH OFF
The LED lights when the mic is on.
MOM OFF
COUGH
MOM. ON
P.T.T.
Architects’ and Engineers’ Specifications
The microphone shall be the Crown Model
CM-312AHS. The microphone shall be a headworn
hypercardioid type of electret-condenser design. The
microphone shall exhibit excellent off-axis response
and gain-before-feedback. The microphone shall have
an adjustable boom with a locking thumbscrew and a
foam pop filter. The microphone shall mount onto
either earpiece of a Sony MDR-7506 or MDR-V6
headphone.
A 4-foot, permanently attached, two-conductor
shielded cable shall connect the microphone to the
belt pack. The belt pack shall include a 3-pin pro
audio (XLR type) connector, battery on/off switch, a
programmable mic on/off switch, and a “Mic On”
LED. The microphone shall be powered by a 9V
battery in the belt pack, or by 18 to 48V phantom
power.
Nominal open-circuit sensitivity shall be 4 mV/Pa.
Maximum SPL shall be 148 dB SPL for 3% THD.
Equivalent noise shall be 31 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 nulls.
The Crown model CM-312AHS is specified.
Crown International, Inc.
P. O. Box 1000
Elkhart, IN 46515-1000
TEL: 574-294-8000
FAX: 574-294-8FAX
www.crownaudio.com
©
2003 Crown Audio, Inc.
Specifications subject to change without prior notice.
Latest information available at www.crownaudio.com.
Crown is a registered trademark of Crown International.
10/03 102549-2
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