Crown Mini-Boundary MB-1 User manual

POLAR
PATTERN
MB-1
MB-1AL
MINI-BOUNDARY
MICROPHONE
Horizontal-Plane Polar Response
Fig. 2
Fig. 1 Frequency Response
The Crown®MB-1 is a miniature bound-
ary microphone for multi-miking applica-
tions such as teleconferencing, distance
learning, boardrooms, and courtrooms.
A low-profile circular microphone, the MB-1 has
a bottom-mounted phone plug. Supplied with
the mic is a table insert with a phone jack that
accepts the mic. The insert flush-mounts in a
hole drilled in the table. After meetings, the mic
can be removed and the insert covered with the
provided disk.
Thanks to its half-supercardioid pickup pattern,
the MB-1 greatly reduces ambient noise and
pickup of room reverberation. The result is a
clearer sound.
The MB-1 must be used with an MB-100 in-
terface (not included). The interface performs
these functions:
• Powers and equalizes up to four mics
• Provides programmable switching to turn
the mic on or off if desired (switches not
provided).
• Pluggable microphone inputs
• Provides balanced outputs from the interface
MB-1 Features
• Painted removable grille assembly
• Miniature mic plugs into jack in table insert
• Clean, clear, natural sound
• Low-Z balanced output prevents hum and
high-frequency loss
• Defeatable LED
• Choice of insert finishes:
Black anodized (MB-1).
Paintable aluminum (MB-1AL)
How to Paint the Microphone
1. Using a small screwdriver, pry open one side
of the base, 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
All specs apply to each output of the interface with a
mic connected.
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 interface output termi-
nal 1 with respect to terminal 3, and on terminal 4
with respect to terminal 6.
Operating voltage (interface): 18-48V phantom power.
Current drain: 5 mA nominal with LED on, 4 mA nomi-
nal with LED off.
Operating temperature range: –10° to +50° C, or +14°
to +122° F.
Mic connector: Stereo phone plug. Mates with stereo
phone jack in supplied insert.
Cable connectors (supplied with MB-100 interface):
• Two pluggable terminal blocks (PTBs) in line with
the microphones. Each input connector handles up
to two mics.
• Two PTBs for output connectors to your mixer.
Each output connector feeds two mixer mic inputs.
• Two PTBs for remote switch sensing. Each PTB
connects to two remote switch sensors.
Cable: None supplied. Use two-conductor shielded mic
cable between phone jack and pluggable terminal
block. Use two-conductor shielded mic cable be-
tween interface output and mixer input. Use twisted-
pair cable between each user switch and interface.
Materials: High-impact molded plastic and steel mesh
mic grille, steel chassis.
Insert Finish: MB-1: black anodized, MB-1AL: alu-
minum.
Net weight: Microphone: 0.7 ounces (19.8 grams).
Table insert: 3.9 ounces (109 grams).
Dimensions: See Figs. 4a and 4b.
Included accessories: Table insert with stereo phone
jack. Disk to cover insert when mic is removed.
*1 pascal = 10 dynes/cm2= 10 microbars = 94 dB SPL.
™
Frequency in Hz
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
+15
+10
+5
dB 0
–5
–10
–15
–20
–25
–30
–35 20 100 1K 10K
130˚
0˚
Features
Perfect for multimiking applications in telecon-
ferencing, distance learning, boardrooms and
courtrooms
Phase Coherent Cardioid®design prevents
coloration from surface sound reflections
Half-supercardioid polar pattern reduces
ambient noise and room reverberation
Very small and inconspicuous
Mic plugs into an insert in the table

Crown International, Inc.
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.
4/08 103275-7
Fig.4a
Fig. 3 Fig.5
Vertical-Plane Polar Response
Installation
1. Typical placement for each mic is at full
arm’s length from the user. Install one micro-
phone 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 in
a cavity or recessed area as the frequency re-
sponse and polar pattern will be degraded.
2. Drill a hole 1.25-in. (3.175-cm) diameter for
each mic’s insert.
3. When you install the insert, make sure that
the locating pin for the microphone is facing
in the desired direction. Orient the mic so the
word “Crown” is readable by the user (right-
side-up).
4. Wire the mic to the MB-100 interface as de-
scribed in the interface data sheet.
5. Plug each mic into its jack. The front of the
mic is indicated by the Crown logo on the mi-
crophone.
6. After use, you may remove the mics and
cover their inserts with the supplied disks.
Architects’ and Engineers’ Specifications
The microphone shall be the Crown model
MB-1 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 shall exhibit excellent off-axis
response and gain-before-feedback. Each mic
shall have a bottom-mounted stereo phone
plug.
A table insert with phone jack shall be included.
The mic shall be used with a pluggable terminal
block and an MB-100 interface (not included).
The interface shall provide operating voltage to
each microphone, and convert its output signal
to low-impedance balanced.
Nominal sensitivity shall be 22 mV/Pa. Maxi-
mum SPL shall be 120 dB SPL for 3% THD.
.680 DIA.
.618"
.153"
.974"
.300"
.379"
1.094 DIA.
1.300 DIA.
1.981"
FRONT
REAR
– 20 –15
–10
–5
–0
60˚ 90˚ 120˚
150
˚
180
˚
0˚
30˚
+5
1 kHz
5 kHz
200 Hz
Fig.4b
1.496" DIA.
(3.8 CM)
.062"
(.2 CM)
1.010"
(2.6 CM)
2.200"
(5.6 CM)
1.025" DIA.
(2.6 CM)
1.250" DIA.
(3.2 CM)
1.130"
(2.9 CM)
BOTTOM VIEW
PHONE PLUG
FRONT
SCREWDRIVER
AFTER REASSEMBLY
RESEAT WASHER
LIFT WASHER AND
PRY OPEN HERE AND
ON OPPOSITE SIDE
Equivalent noise shall be 22 dBA nominal. Fre-
quency 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-1 and MB-1AL are
specified.
Warranty
Crown professional microphone products 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 config-
ured and connected as described in the MB-
100 interface data sheet. Check the slide-switch
setting in the interface. If there is hum or no
signal, first repair or replace the cable.
If it is determined that the microphone needs
additional service and you wish to return it to
Crown, a Service Return Authorization (SRA)
is required. An SRA can be completed online
at www.crownaudio.com/support/factserv.htm.
After securing an SRA, return the microphone
in its original packaging to: Crown Factory
Service, 1718 W. Mishawaka Road, Elkhart,
IN 46517-9439.
For further assistance or technical support call
800-342-6939.
MB-1
MB-1AL