DIFFEROID® MICROPHONE
WITH ON/OFF SWITCH
CM-310ASW
T
he Crown CM-310ASW Differoid® is a
hand-held noise-canceling microphone
for sporting events or other applications with high ambient sound level. It
features a magnetic reed switch that turns
the mic on and off. The smooth-operating
switch operates silently.
The CM-310ASW uses Crown’s patented
Differoid technology. It is differential or
noise cancelling, so it rejects sounds that
are not close to the microphone. It has a
cardioid polar pattern, so it rejects sounds
from the rear.
These features give the CM-310ASW exceptional gain before feedback. It permits extremely loud P.A. levels before feedback
occurs. The mic also rejects unwanted
background noise. The announcer can sit in
the stands with the audience, with the P.A.
loudspeakers playing loudly, and not experience feedback.
Inside the mic handle, on the PC board is a
DIP switch that sets the frequency response.
It has two settings: music and announcing.
The music setting sounds warm and
smooth, while the announcing setting has
less bass and more highs for extra intelligibility.
The frequency response is tailored for clear,
natural reproduction of the voice. A built-in
pop filter suppresses explosive breath
sounds. Handling noise is very low. The unit
can withstand repeated drops and abuse, as
well as extremely loud sounds without
distortion.
The output of the CM-310ASW is balanced,
low impedance, which allows long cable
runs without hum pickup or high-frequency
loss. The unit can be phantom powered from
a mixer or other remote power supply.
Included with the CM-310ASW is a convenient carrying pouch, the ASA-2 mic stand
adapter, and a foam windscreen for outdoor
use.
Operating Instructions
Using a 2-conductor shielded microphone
cable, plug the microphone into a mixer mic
input with 12 to 48 volts phantom powering
or use a remote phantom power supply.
Crown makes an AC-powered model PH-4B
supply for powering up to four microphones. Also available is a single-channel
Specifications
Transducer type: Electret condenser.
Frequency response (typical): 80 Hz to 15 kHz. See
Figs.1 and 2.
Polar pattern: Cardioid. See Fig. 3.
Impedance: 200 ohms balanced. Recommended
minimum load impedance 1000 ohms.
Open circuit sensitivity, typical, close talking:
1.7 mv/Pa* (–55.5 dBV/Pa).
Power sensitivity, typical, close talking: –54.5
re 1 mW/Pa*.
Equivalent noise level (self-noise): 21.5 dB SPL
typical (0 dB = .0002 dyne/cm2), A-weighted.
S/N ratio: 72.5 dB at 94 dB SPL.
Maximum SPL for 3% THD: 151 dB SPL with 48 V
phantom, 143 dB SPL with 12 V phantom.
Operating voltage: Phantom power, 12 to 48 volts
DC, positive voltage on pins 2 and 3 with respect to
pin 3 of output connector.
Polarity: Positive pressure on the diaphragm
produces a positive voltage on pin 2 with respect
to pin 3 of output connector.
Current drain: 1.5 milliamperes.
Cable: None supplied. Use 2-conductor shielded mic
cable.
Connector: 3-pin professional audio connector (XLR
type).
Switch: Magnetic reed on/off.
Materials: Rugged aluminum alloy housing, steel
grille.
Finish: Satin black.
Net weight: 7.1 oz. (200 g).
Dimensions: See Fig.4.
Included accessories: Carrying pouch, ASA-2 mic
stand adapter and WS-4 windscreen.
Optional accessories: Crown PH-1A phantom power
supply (1 channel, battery or AC adapter powered),
Crown PH-4B phantom power supply (4 channels,
AC powered).
Replacement parts: Field-replaceable CM-310ASW
grille screen is available from Crown’s Parts
Department.
*1 pascal = 10 dynes/cm2 = 10 microbars = 94 dB
SPL.
Fig. 1
Frequency Response
(switch set to “announcing”)
+15
+10
0˚ ¼ inch
+5
dB 0
–5
–10
0˚ 2 feet
–15
–20
–25
–30
–35
20
100
10K
1K
20K
Frequency in Hz
Fig. 2
Frequency Response
(switch set to “music”)
+15
+10
0˚, 0 Inches
+5
dB 0
–5
0˚, 2 Feet
–10
–15
–20
–25
160˚, 2 Feet
–30
–35
20
100
10K 20K
1K
Frequency in Hz
Fig. 3
Polar Response
330˚
0˚
30˚
FRONT
–0
300˚
60˚
–5
–10
–15
–20
270˚
90˚
500-3500 Hz 120˚
250 Hz
10 kHz
240˚
REAR
210˚
180˚
150˚
Fig. 4
CM-310ASW
Fig. 6
2.020"
.840"
7.335"
Fig. 5
tial-type condenser requiring 12 to 48 volts
phantom powering. Included shall be a
magnetic reed switch to turn the microphone on and off. The microphone shall a
have 2-position dip switch for setting the
frequency response for announcing or
music.
1:1 XFMR
TO MIC
1
CT
2
2
3
1
3
TO MIXER
MIC INPUT
+
18V (TWO 9-V ALKALINE)
100mF 25V
TO MIC
1
2
1K
3
A smooth frequency response from 80 Hz to
15 kHz shall be obtained, with a uniform offaxis response. The polar pattern shall be
cardioid. The microphone shall have an
open-circuit sensitivity of 1.7 mV/Pa*. The
microphone shall accept a 151 dB SPL input
while providing no greater than 3% THD
(open-circuit termination). Equivalent noise
shall be 21.5 dBA typical (0 dB = .0002
dyne/cm2). The Crown model CM-310ASW
microphone is specified.
Fig. 7
+
1K
2
100mF 25V
+
1
TO MIXER
MIC INPUT
DIP SWITCH
3
+
18V (TWO 9-V ALKALINE)
MATCH RESISTORS WITHIN 1% (10 OHMS)
battery supply or AC-adapter supply, Crown
model PH-1A. For special applications, you
can make your own battery supply as suggested in Fig. 5.
ANNOUNCING
Since the microphone cancels sounds that
are not close to the mic, you must talk
close to the microphone with lips touching
the grille-screen; talk directly into the
front of the microphone (as in Fig. 6).
MUSIC
1. Remove the screw in the mic handle near
the connector.
2. Using needlenose pliers, pull on the
connector pins to pull out the circuit board.
Be careful not to break the wires soldered to
the board.
To reduce wind noise or breath popping,
place the included foam windscreen on the
microphone. Note: This will reduce the
mic’s noise-canceling ability.
3. Set the DIP switch as shown in Fig. 7 and
reassemble the mic.
Architects’ and Engineers’ Specifications
The microphone shall be the Crown model
CM-310ASW Differoid or equivalent. The
microphone shall be a hand-held differen-
The switch inside the mic is factory-set to
“announcing.” To change the switch to
“music,” you need to pull out the circuit
board in the mic.
Warranty
Crown professional microphones are guaranteed unconditionally against malfunction
from any cause 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 unit fails to work, first replace or
repair the mic cables and check the power
supply. If service is required, return the
microphone in its original packaging to
Crown’s Service Department at Plant 2SW,
1718 W. Mishawaka Road, Elkhart, IN
46517. For further assistance or technical
support call 800-342-6939.
+
W1
B+
Q1
S
R5
R3
S1A
AUDIO
R6
C2 R4
C1
R1
R2
W2
R6
C3
R1
C1
R5
C2
R3
R4
T1
W6
RED
GRN
C8
R10
1
2
W8
Q2
+
S1B
W4
C6
C4
R2
W5
®
BLK
BLU
W5
R7
R9
GND
W6
R8
Q1
W2
W3
TO
CAPSULE
GND
C5
W4
D
+
G
+
TO
CAPSULE
HOT
+
W1
W7
C7
R11
S2
R12
W9
3
P1
OUTPUT
S1C
W3
CAPSULE ELECTRONICS
ELECTRONICS IN HANDLE
1998 Crown International, Inc.
Specifications subject to change without prior notice.
Crown® is a registered trademark of Crown International, Inc.
©
CM-310ASW Schematic
Crown International, Inc.
P.O. Box 1000
Elkhart, IN 46515-1000
TEL: 219-294-8000
FAX: 219-294-8FAX
Internet: http://www.crownaudio.com
9/98
100389-1