Crown Audio CM-312AE User Manual

POLAR
PATTERN

CM-312AE

HYPERCARDIOID HEADWORN
CONDENSER MICROPHONE

he Crown® CM-312AE is a rugged, lightweight
headworn microphone designed for aerobics,

T

live entertainment, and sports broadcasting. It is

intended for wireless-mic applications that require a
light, inconspicuous mic.

The CM-312AE has no connector; you solder on a
connector that mates with a wireless transmitter of
your choice. Technical Bulletin #3 (included) shows
the correct wiring for various transmitters.

Because the microphone is to the side of the mouth,
breath pops are eliminated. The sound of the
CM-312AE can be tailored to taste by moving the
microphone closer or farther from the corner of the

mouth.

The CM-312AE sounds like the best handheld mi­crophones. Its hypercardioid pickup pattern reduces
feedback and aids isolation. In diffi cult situations, the
Crown CM-311AE headworn mic is recommended
because it picks up even less feedback and leakage

than the CM-312AE.

Designed for comfort, the headband fi ts behind the
head and disappears in use. Both the headband and
boom adjust to fi t any head. Because of the boom’s
unique behind-the-ear design, it does not cover up the

user’s face.

How to adjust for best fi t

For best results, the CM-312AE MUST be custom fi t­ted to one wearer’s head. This simple procedure takes
only a few minutes. Please refer to Fig. 3 and locate

the parts described.

1. If the microphone is for yourself, we suggest that
you use a mirror to double check the fi t 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 adjust the headband to fi t your head. Put the
foam block wire behind your ear.

Start bending the headband wire from the boom
side, moving around to the other ear. The back of the
headband should fi t fi rmly against the back of the
neck. If you can slide a fi nger between the headband
and the back of your neck, then the headband is not
fi tted correctly. For users with smaller or petite heads,
you may have to re-bend the earpiece around the ear,
and cut off extra headband material.

4. Next, adjust the foam pad snug against your head
or neck. To do this, bend the wire that goes into the
foam block. CAUTION! Do not bend the boom itself
– just the foam-block wire. A snug fi t of the foam pad
prevents boom bounce when you move around.

Specifi cations

Transducer type: Electret condenser.

Frequency response (typical): 50 Hz to 17,000 Hz (see

Fig. 1).

Polar pattern: Hypercardioid (see Fig. 2).

Impedance: 6 kilohms unbalanced.

Recommended load impedance: 10 kilohms.

Open-circuit sensitivity, typical, close-talking:

2.9 mV/Pa* (–51 dB re 1V/Pa*).

Power sensitivity, typical, close-talking:

–65 dB re 1 mW/Pa*.

Equivalent noise level (self noise): 31 dB SPL typical

(0 dB = 0.0002 dyne/cm

S/N ratio: 63 dB at 94 dB SPL.

Maximum SPL: 148 dB SPL produces 3% THD.

Operating voltage: 3–9V DC from the transmitter’s battery.

Polarity: Positive pressure on diaphragm produces posi-

tive voltage on white lead with respect to shield.

Current drain: 0.27 mA nominal.

Battery life: Approximately equal to transmitter battery

life.

Operating temperature range: –18° to +57° C, or 0° to

+135° F.

Off-attenuation: 70 dB @ 1kHz.

Output connectors: Supply your own to match your

transmitter.

Cable: 45-inches long (1.14-m), 2-conductor shielded

unbalanced cable, unterminated. In-line with this cable
is a small circuit module that equalizes the microphone
signal. White lead is audio, red lead is DC bias, and
shield is ground.

Materials: High-impact plastic and PVC mic housing,

brass boom, steel wire headband.

Finish: Satin black.

Net weight: 1.5 oz (43 g).

Dimensions: Headband 5.5 in. (13.97 cm) diameter,

adjustable. Boom approximately 5.75 in. (14.61 cm).
See Fig. 6.

Included accessories: Microphone carrying case, WS-7

foam pop fi lter and clothing clip for aerobics.

*1 pascal = 10 dynes/cm2 = 10 microbars = 94 dB SPL.

2

), A-weighted.

Fig. 1

+15
+10

+5

0

dB

-5

-10

-15

-20

-25

-30

-35

20 100

Fig. 2

300°

270°

240°

Fig. 3 Parts

EARPIECE

HEADBAND

WIRE

FOAM BLOCK

WIRE

FOAM BLOCK

THUMBSCREW

TO MOVE MIC

IN OR OUT

Frequency Response

0°, 1.375 in.

0°, 2 ft.

120°, 2 ft.

Frequency in Hz

Polar Response

330°

FRONT

REAR

210°

1K

0°

-0

-5

-10

-15

-20

DETAIL

TO MOVE MIC

UP OR DOWN

TO MOVE MIC

LEFT OR RIGHT

BOOM

20K

10K

30°

60°

90°

120°

1000 Hz
300 Hz
6000 Hz

150°180°

MIC

CM-312AE

The closer the mic is to your mouth, the bassier is the
tone. Adjust the position for the sound you prefer. If
you hear breath pops, move the mic farther to the side
of your mouth (Fig. 4). Tighten the thumbscrew.

Fig. 4

Adjust mic position to prevent breath pops.

Once you’ve adjusted the headset, it should remain in
that position – no further adjustments are needed.

When using the mic for aerobics, you’ll need to keep
the cable in place. To do this, attach the cable to the
clothes clip (included), and clip it to the back of your
shirt. As shown in Fig. 5, be sure that the cable droops
BELOW the clip. That way, sweat drips off the cable
instead of into your transmitter.

Additional clothing clips can be ordered from Crown’s
Parts Department.

How to connect the CM-312AE to a wireless trans­mitter

1. Solder on a connector that mates with your trans­mitter. Technical Bulletin #3 (included) shows the
correct wiring for various transmitters.

2. Plug in the cable. Adjust the trim pot on the trans­mitter input to prevent distortion.

Architects’ and Engineers’ Specifi cations

The microphone shall be the Crown Model CM-312AE
or equivalent. 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 headband, adjustable boom with locking
thumbscrew, and foam pop fi lter.

The microphone shall have a 45-inch (1.14-m),
permanently attached, two-conductor shielded unter­minated cable that can be connected to a transmitter.
Powering shall be 3–9V from the transmitter.

Nominal open-circuit sensitivity shall be 2.9 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-312AE is specifi ed.

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 datasheet.

If you determine that the microphone product is defec­tive, return the complete product in its original pack­aging to Crown Factory Service, 1718 W. Mishawaka

Road, Elkhart, IN 46517-9439. A Service Return
Authorization (SRA) is required for product being
returned for service. An SRA can be completed on
line at:
www.crownaudio.com/support/factserv.htm.

For further assistance or technical support call 800­342-6939.

Fig. 5 Let the cable droop below the clip to

shed moisture.

Fig. 6

Dimensions

Crown International, Inc.
1718 W. Mishawka Rd.
Elkhart, IN 46517-9439
TEL: [phone]
FAX: [phone]FAX
www.crownaudio.com

®

© 2008 Crown Audio
to change without prior notice. Latest information
available at www.crownaudio.com. Crown and
Crown Audio are registered trademarks of Crown
International.

4/08 102547-7A

, Inc. Specifi cations subject