Crown MINI-BOUNDARY MB-4 User manual

POLAR
PATTERN
MB-4
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.
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.
• 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.
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
response and polar pattern will be degraded.
2. Orient the mic so the word “Crown” is read-
able by the user (right-side-up).
3. Plug a mic cable with a female XLR-type con-
nector 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.
.
Specifications
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: Positive (inward) pressure on the diaphragm
produces positive voltage on pin 2 with respect to
pin 3.
Operating voltage: Phantom power, 12-48 volts DC
on pins 2 and 3 with respect to pin 1 of output
connector.
Current drain: 4 mA nominal. .
Connector: 3-pin pro audio, XLR-type.
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.
Materials: High-impact molded plastic and steel mesh
mic grille, steel power module.
Finish: Satin black.
Operating temperature range: –10° to +50° C, or
+14° to +122° F.
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: PH-1A phantom power supply
(1 channel, battery or DC-adapter powered).
*1 pascal = 10 dynes/cm2= 10 microbars = 94 dB SPL.
™
Fig. 2 Vertical-Plane Polar Response
Frequency in Hz
Fig. 1
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
Fig. 3
Horizontal-Plane Polar Response
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
Frequency Response

Crown International
1718 W. Mishawaka Rd.
Elkhart, IN 46517-9439
TEL: [phone]
FAX: [phone]FAX
www.crownaudio.com
©2008 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.
4/08 103278-6
Fig.4
MB-4
Architects’ and Engineers’ Specifications
The microphone shall be the Crown model
MB-4 or equivalent. The microphone shall be a
half-supercardioid electret condenser type. The
microphone shall use the principle of phase co-
herency achieved by mounting a small-diameter
element very near a boundary. This eliminates
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.
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 model MB-4 is specified.
Fig.5
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. If
the mic is defective, return the microphone and
the interface in their original packaging to Crown
Factory Service, 1718 West Mishawaka Road,
Elkhart, IN 46517-9439.
A Service Return Authorization (SRA) is re-
quired for product being sent to the factory for
service. An SRA can be completed on line at
www.crownaudio.com/support/factserv.htm.
For further assistance or technical support call
800-342-6939.
BOTTOM VIEW
SCREWDRIVER
PRY OPEN HERE AND
ON OPPOSITE SIDE