Crown Audio MB-4E specifications Features, Ideal for teleconferencing, distance, Specifications

POLAR

PATTERN

MB-4

MB-4E

he Crown® MB-4 is a miniature boundary Tmicrophone 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.

MINI-BOUNDARY™

MICROPHONE

Features		• Half-supercardioid polar pattern reduces
•	Ideal for teleconferencing, distance	feedback, room acoustics and background
	learning, boardrooms and courtrooms	noise
•	Has a 15-foot attached cable leading to an	• Clear, natural sound
	XLR-type output connector with built-in

mic electronics

• Small and inconspicuous

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. 1

Frequency Response

+15
+10
+5		0˚
dB 0
–5
–10		130˚
–15
–20
–25
–30
–35	100	1K	10K
20

Frequency in Hz

Fig. 2

Vertical-Plane Polar Response

60˚		90˚	120˚
			1 kHz
			200 Hz
			5 kHz
30˚			150˚
FRONT			REAR
0˚	–5	–10 –15 –20	180˚
+5 –0