Crown Audio MB-4 - Manual

POLAR
PATTERN
MB-4
MB-4E
T he Crown ® MB-4 is a miniature boundary
microphone for multi-miking applications
such as teleconferencing, distance learning,
boardrooms, courtrooms, and TV or theatrical
applications. Double-sided sticky tape is pro-
vided for attaching the unit under shelves, on
walls, etc.
Thanks to its supercardioid pickup pattern, the
MB-4 greatly reduces ambient noise and pickup
of room reverberation. The result is a clearer
sound.
The MB-4 has a 15-foot attached cable leading
to an XLR-type output connector with built-in
mic electronics. It is powered by 12-48V phan-
tom power, and is low-impedance balanced.
The MB-4E is the same, but without the elec-
tronics/connector.
The MB-4E must be used with the Crown MB-
100 or MB-200 interface (not included). The
interface provides these functions:
• Powers and equalizes up to four mics.
• Provides programmable switching to turn
the mic on or off if desired (switches not
provided).
• The MB-200 interface also has remote
switch sensing via an optical coupler.
• Pluggable microphone inputs.
• Provides balanced outputs from the inter-
face.
Features
• Tiny, inconspicuous.
• Can be used without putting holes in the
table.
• Clean, clear, natural sound.
• Low-Z balanced output prevents hum and
high-frequency loss.
• LED indicates mic on (MB-4E only).
• LED in MB-4E is defeatable.
• Switches can be internally programmed
for touch-on/touch-off, momentary on, or
momentary off.
• Remote sensing of switch closure (in MB-
200 interface).
• Removable grille assembly can be painted.
How to Paint the Microphone
1. Using a small screwdriver, pry open one side
of the grille, then the other side (Fig. 5).
2. Remove foam liner.
3. Wearing a dust mask, spray-paint the grille
assembly. Be sure grille holes are not clogged.
4. Allow paint to completely dry.
5. Make sure the LED is properly aligned.
6. Carefully place the grille assembly over the
LED, and snap in place.
Specifi cations
MB-4 specifi cations are at the mic cable connec-
tor. MB-4E specifi cations are at the interface output
terminals.
Type: Phase Coherent Cardioid.
Element: Electret condenser.
Frequency response (typical): 50 Hz to 15,000 Hz at
30 degrees incidence to surface (see Fig. 1).
Polar pattern: Half-supercardioid (supercardioid in
the hemisphere above the primary boundary). See
Figs. 2 and 3.
Impedance: 150 ohms, balanced (recommended load
impedance 1000 ohms or greater).
Open-circuit sensitivity (typical): 22 mV/Pa* (–33
dB re 1 volt/Pa).
Power sensitivity: –30.5 dB re 1 mW/Pa.* EIA rating
–125 dBm.
Equivalent noise level (self-noise): 22 dB SPL typical
(0 dB=0.0002 dyne/cm 2 ), A-weighted.
S/N ratio: 72 dB at 94 dB SPL.
Maximum SPL: 120 dB SPL at 3% THD.
Polarity (MB-4): Positive (inward) pressure on the
diaphragm produces positive voltage on pin 2 with
respect to pin 3.
Polarity (MB-4E): Positive (inward) pressure on
diaphragm produces positive voltage on interface
output terminal 1 with respect to terminal 3, and on
terminal 4 with respect to terminal 6.
Operating voltage (MB-4): Phantom power, 12-48
volts DC on pins 2 and 3 with respect to pin 1 of
output connector.
Operating voltage (MB-4E): 18-48V phantom power
at interface output.
Current drain (MB-4): 4 mA nominal.
Current drain (MB-4E): 4 mA nominal with LED off, 5
mA nominal with LED on.
Connector (MB-4): 3-pin pro audio, XLR-type.
Connector (MB-4E): Pluggable terminal block (one
block per every two microphones).
Cable: Permanently attached, black, 15-foot (4.572-
m), 2-conductor shielded cable from mic to power
module or interface. No other cable supplied. Use
two-conductor shielded mic cable from power
module to mixer, or from MB-100 Interface to
mixer.
Materials: High-impact molded plastic and steel mesh
mic grille, steel power module.
Finish: Satin black.
Net weight: Microphone: 0.7 ounces (19.8 grams).
Power module: 2.8 ounces (78.6 grams).
Dimensions: See Fig. 4.
Included accessories: Double-sided tape for fastening
under shelves, etc., for theatrical applications.
Optional accessories (MB-4 only): PH-1A phantom
power supply (1 channel, battery or DC-adapter
powered).
Required accessory (MB-4E only): Crown MB-100 or
MB-200 Interface.
*1 pascal = 10 dynes/cm 2 = 10 microbars = 94 dB SPL.
™
Fig. 2
Vertical-Plane Polar Response
Frequency in Hz
Fig. 1
Frequency Response
FRONT REAR
– 20 –15 –10 –5 –0
60˚ 90˚ 120˚
150˚
180˚ 0˚
30˚
+ 5
1 kHz
5 kHz
200 Hz
+15
+10
+5
dB 0
–5
–10
–15
–20
–25
–30
–35
20 100 1K 10K
130˚
0˚
Features
• Ideal for teleconferencing, distance
learning, boardrooms and courtrooms
• Has a 15-foot attached cable leading to an
XLR-type output connector with built-in
mic electronics
• Half-supercardioid polar pattern reduces
feedback, room acoustics and background
noise
• Clear, natural sound
• Small and inconspicuous
MINI-BOUNDARY
MICROPHONE