Shure 444 - User Manual

CONTROLLED MAGNETICm COMMUNICATIONS MICROPHONE
222 HARTREY AVE.. EVANSTON. IL. 60204 U.S.A.
@
AREA CODE 3121866-2200 . CABLE: SHUREMICRO
TWX: 910-231-0048 TELEX: 72-4381
GENERAL
DATA MODEL 444
SHEET
COMMUNICATIONS
MICROPHONE
The Model 444 is a pressure-operated CONTROLLED
MAGNETIC@ microphone. It is specifically designed for
radio communication applications and provides opti-
mum performance from single sideband transmitters
as well as AM and FM units. The response cuts off
sharply below 300 and above 3,000
Hz, with a rising
characteristic to 3,000
Hz. This special response char-
acteristic results in optimum speech intelligibility and
audio punch to cut through noise and interference.
i
Microphone Features:
A response tailored for single sideband transmis-
sions
w
A switch for instantaneous selection of Press-to-
Talk or VOX (voice-operated relay control) oper-
ation
CONNECTIONS
.
Finger-tip control bar (locking or non-locking ac-
Model 444 is designed for use with transmitters or
tion) to actuate microphone and an external relay
amplifiers having high-impedance inputs. The BLACK
or control circuit
cable lead is the
"hot" conductor for the microphone
circuit: the WHITE cable lead controls an external relav
.
~ong-life switch to satisfy severe requirement of
circuit. The shield is common to both the microphone
communication systems
circuit and the external relay circuit. The shield should
be securely grounded to the amplifier or transmitter
Adjustable microphone height chassis ground. (See Figure 1 for internal wiring
w
A sturdy, high impact ARMO-DUR@ base and mi-
diagram of Model 444.)
crophone case
r\
Dependability-under all operating conditions BLACK
GROUNDED TERMINAL
INTERNAL CONNECTIONS
SHIELD 7
PRESS-TO-TALK SWITCH OPERATION
NORMAL-VOX OPERATION
6G-3
OF CARTRIDGE
-
Most amateur equipment is wired to use either VOX
(voice-operated relay control) or a Press-to-Talk switch.
Model 444 has been designed to provide maximum
flexibility for both types of operation. VOX or
Press-
to-Talk operation may be easily selected by the
Normal-Vox slide switch on the bottom side of the
microphone base near the cable entry.
For Press-to-Talk operation of the microphone, the
Normal-Vox switch should be in the "Normal" position.
For VOX operation, the Normal-Vox switch should be
in the "VOX" position, and the Press-to-Talk switch
must be locked in the On position.
The finger-tip control bar can be used as a locking
m-----
i \ !\ BLACK
or nonlocking switch. To use as a nonlocking switch,
I I ; ! WHITE
FIGURE 1
simply depress the control bar and release after trans-
mission. To use as a locking switch, depress the
PRESS-TO- TALK
IMPORTANT
Shure Microphone Cables are selected after ex-
haustive tests to insure superior performance in micro-
phones because of low capacitance, superior shielding
properties and unusually long life under severe use.
Cables with plastic insulation should not be sub-
jected to excessive soldering-iron heat. Carefully clean
and tin the conductors and the connections to which
the conductors are to be soldered. The soldering
operation can then be done with a minimum of heat,
thereby avoiding any possibility of damage to the
cable.
\{
----
!: SHIELD
NORMAL -VOX
Copyright 1978, Shure Brothers Inc.
27A245 (RJ)
(OVER)
control bar and pull it forward. To unlock the switch,
t
SWITCH -
- iO1 ?- I,,) SWITCH SHOWN IN
'NORMAL" POSITION
U.S. Patent D-198,850
Printed in U.S.A.
move the bar back and release.
YELLOW j

Summary

CONTROLLED MAGNETIC COMMUNICATIONS MICROPHONE

GENERAL

The Model 444 is a pressure-operated CONTROLLED MAGNETIC microphone designed for optimal performance in radio communication applications.

Microphone Features

Lists features like tailored response, PTT/VOX switch, adjustable height, and durable construction.

PRESS-TO-TALK SWITCH OPERATION

Explains how to use the finger-tip control bar as a locking or nonlocking switch for transmission.

CONNECTIONS

Details how the Model 444 connects to high-impedance inputs and wiring for relay circuits.

NORMAL-VOX OPERATION

Describes how to select between VOX or Press-to-Talk operation using the Normal-Vox switch.

SPECIFICATIONS

Type

Specifies the microphone type as CONTROLLED MAGNETIC®.

Frequency Response

Details the frequency response curve from 200 to 6,000 Hz, shown in Figure 2.

Polar Pattern

Indicates the microphone has an Omnidirectional polar pattern.

Impedance

States the microphone impedance is 'High' for high-impedance inputs, with load impedance range.

Output Level

Provides output level specifications in dB for open circuit and loaded conditions.

Switch

Describes the function of the Press-to-Talk and Normal-Vox switches.

Cable

Details the non-detachable 2.1m (7 ft) shielded cable.

Case

Specifies the case material as two-tone gray ARMO-DUR®.

Dimensions

Provides overall dimensions of the microphone, illustrated in Figure 3.

Net Weight

States the net weight of the microphone is 680 grams (1.5 lb).

Packaged Weight

States the packaged weight is 964 grams (2.125 lb).

REPLACEMENT PARTS

Lists available replacement parts such as cartridge, cable, and switches.

GUARANTEE

Details the one-year warranty against defects and limitations.

SHIPPING INSTRUCTIONS

Provides instructions for returning the unit for repair or service.

Shure 444 Specifications

General

Type	Dynamic
Polar Pattern	Cardioid
Impedance	150 ohms
Connector	3-pin XLR
Frequency Response	50-15, 000 Hz