Crown MINI-BOUNDARY MB-4E User manual

POLAR
PATTERN
MB-4
MB-4E
The 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.
Specifications
MB-4 specifications are at the mic cable connec-
tor. MB-4E specifications 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/cm2), 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/cm2= 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
–3520 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

Crown International
1718 W. Mishawaka Rd.
Elkhart, IN 46517-9439
TEL: [phone]
FAX: [phone]FAX
www.crownaudio.com
©2005 Crown Audio®Inc. Specifications subject to change
without prior notice. Latest information available at www.
crownaudio.com. Mini-Boundary is a trademark, and Crown
and Crown Audio are registered trademarks of Crown
International. Printed in U.S.A.
7/05 103278 -5A
Fig.4
Fig. 3 MB-4
MB-4E
Installation
1. Typical placement for each mic is at arm’s
length from the user. Install one microphone in
front of each person, or one between every two
people.
If the microphone will be used on a lectern,
install it on an open surface. Do not install it in
a cavity or recessed area as the frequency re-
sponse and polar pattern will be degraded.
2. Orient the mic so the word “Crown” is read-
able by the user (right-side-up).
3. MB-4 only: Plug a mic cable with a female
XLR-type connector into the power module.
Connect the other end of the cable to a phantom
power supply. Or if your mixer has phantom
power, connect the mic cable directly to a mic
input and turn on phantom power.
Wire the MB-4E to the MB-100 or MB-200 inter-
face as described in the interface data sheet.
Fig.5
Horizontal-Plane Polar Response
Architects’ and Engineers’ Specifications
The microphone shall be the Crown model MB-
4, MB-4E, or equivalent. The microphone shall
be a half-supercardioid electret condenser type.
The microphone shall use the principle of phase
coherency achieved by mounting a small-diam-
eter element very near a boundary. This elimi-
nates comb filtering in the audible spectrum.
The microphone will exhibit excellent off-axis
response and gain-before-feedback. The MB-
4 shall have a permanently attached 15-foot
(4.572-m) cable connected to an XLR-type con-
nector with built-in mic electronics. Powering
shall be by 12-48V phantom power. The MB-4E
shall have a permanently attached 15-foot
(4.572-m) cable without electronics/connector.
Its powering shall be by the Crown MB-100 or
MB-200 Interface.
At the output connector, nominal sensitivity shall
be 22 mV/Pa. Maximum SPL shall be 120 dB
SPL for 3% THD. Equivalent noise shall be 22
dBA nominal. Frequency response shall be 50
Hz to 15 kHz with a uniform off-axis response,
about 20 dB down at the rear nulls.
The Crown models MB-4 and MB-4E are speci-
fi e d .
Warranty
Crown professional microphones are guaranteed
against malfunction for a period of three years
from date of original purchase. See enclosed
warranty sheet for additional information.
Service
If the microphone does not function properly,
check that it is aimed correctly and is connected
as described in this data sheet. If there is hum
or no signal, first repair or replace the cable. For
the MB-4E only, check the slide-switch setting
in the MB-100 or MB-200 Interface. If the mic is
defective, return the microphone and the inter-
face in their original packaging to Crown Factory
Service, 1718 West Mishawaka Road, Elkhart,
IN 46517-9439. For further assistance or techni-
cal support call 800-342-6939.
FRONT
REAR
0˚ 30˚
60˚
90˚
120
˚
150˚
180˚
210˚
240˚
270˚
300˚
330˚
–20
–15
–10
–5
–0
1 kHz
5 kHz
200 Hz
BOTTOM VIEW
SCREWDRIVER
PRY OPEN HERE AND
ON OPPOSITE SIDE