Transcript
HYPERCARDIOID CONDENSER MICROPHONE FOR USE WITH SONY MDR-7506 AND MDRV6 HEADPHONES
CM-312AHS
T
he Crown® CM-312AHS is a rugged, lightweight head-worn microphone that mounts on 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 head-worn mic is recommended because it picks up even less feedback and leakage than the CM312AHS. The microphone adjusts to fit any user. It mounts securely on either earpiece of the popular Sony MDR-7506 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 electret-condenser 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. 5. 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. 6 and follow this procedure:
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, closetalking: 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/cm2), Aweighted. 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. 3 and 4. 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.
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.
Changing the mic position changes the ratio of lows to highs. Adjust the position for the sound you prefer.
3. Replace the batttery cover. Connect the belt pack to the mixer using a 2conductor 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 phantompower supply (such as the Crown PH-1A or PH-4B).
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 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.
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.
How to adjust for fit The CM-312AHS can be adjusted to fit any user. Please refer to Fig. 5 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).
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
4. Tighten the thumbscrew. 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.
S3
BT1 9V VCC
W10
W5 W6 D3
RED
C9
FB1
C8
W3
WHT
R13
3 2
SHIELD
R29
R15 C6
8
U3A 1
C12 R22
4
R14
U4 3
C17
R24
W4
Q3
MICROPHONE CAPSULE
VCC
R16 VCC
R12
C5
5
Q4
C10
R19
U2A 14 6 5 1 3 D S Q CLK 2 R Q
C1 C3
C15
R5
4
7 R3
Q5 R17
C19
R18
R26
R21 5 6
U3B 7
C13 R23
R11
1
U1A 2
U1E 5
U1B 4
11
8 C16
C7 E1
R8
W2
3
R1
D1
7
6 U1C
R28
WHT W9
R4 Q1
9
U1D 10
Q2 12 R9
4 3 2
SHIELD W8
C11
VCC
R7
D4
C14
C4
R2
S1
6
R25
R20
C2
GRN W7 R27
7
R10
R6
W1
2 1
4
1 S2
MICROPHONE ELECTRONICS
CM-312AHS Schematic
Fig. 1
Fig. 2
Frequency Response
Polar Response
+15
330˚
0˚, 1.375"
+5
-0
300˚
dB 0
60˚
-5 -10
-5
-15 -20
-10 270˚
-15
90˚
0˚ 2'
-20 -25
120˚, 2'
-30 -35 20
30˚
0˚ FRONT
+10
240˚
100
1K
1000 Hz 300 Hz 6000 Hz
REAR
10K 20K 210˚
Frequency in Hz
Fig. 3
120˚
180˚
150˚
Fig. 4
3"
1.062" (2.7 cm)
2"
5.75"
3.745" (9.5 cm)
.680" (1.7 cm)
Fig. 5 2.593" (6.6 cm)
YOKE
Fig. 6
MOUNT
PIN
BLOCK MIC
Typical mic position at one side of the mouth. If you hear breath pops or a nasal sound, move mic sideways away from mouth.
BLOCK INNER HALF
BOOM
THUMBSCREW THUMBSCREW
BLOCK OUTER HALF
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 beltpack case by removing the three screws. Set the switch as shown below: TO XLR
PUSH ON/ PUSH OFF
MOM OFF (COUGH)
MOM. ON (P.T.T.)
The LED lights when the mic is on. Architects’ and Engineers’ Specifications The microphone shall be the Crown Model CM-312AHS or equivalent. The microphone shall be a head-worn 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 to 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.
CM-312AHS 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 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 Service Department, Plant 2 SW, 1718 West Mishawaka Road, Elkhart, IN 46517. For further assistance or technical support call 800-3426939.
The Crown model CM-312AHS is specified. Warranty
@crown
®
Crown International, Inc. P. O. Box 1000 Elkhart, IN 46515-1000 TEL: 219-294-8000 FAX: 219-294-8FAX
©1997 Crown International, Inc. Specifications subject to change without prior notice. Crown® is a registered trademarks of Crown International, Inc.
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