Page 1
222 HARTREY AVE.. EVANSTON. IL. 60204 U.S.A.
8
8
AREA
CODE
AREA CODE 3121866-2200 CABLE: SHUREMICRO
TWX: 910-231-0048 TELEX:
UNIDIRECTIONAL DYNAMIC MICROPHONES
3121866.2200 CABLE: SHUREMICRO
72-4381
UAIA
1
:K~T
SHEET
I
MODELS 548,548SD,
and
,
and
UNIDYNEm IV
UNIDYNE~
SERIES
SERIES
IV
548SH
548SH
I
I
GENERAL
The UNIDYNEB IV Models 548,548SD, and 548SH are
dual-impedance unidirectional dynamic microphones
shipped connected for low-impedance operation. The
units provide wide range reproduction of music and
voice and can be effectively used outdoors and indoors.
The UNIDYNE
entertainers in high quality theater-stage sound sys-
tems and recording, as well as in critical public-address
systems such as those used in political conventions
and legislatures, convention halls, hotels, public audi-
toriums, stadiums, cathedrals and churches.
The UNIDYNE
directional pickup pattern that provides an effective . Built-in long-life On-Off switch (548SH, 548SD, and
solution to feedback problems in reverberant locations,
permits best utilization of space in small studios,
facilitates orchestral placement,
wanted background noise. the microphone
The UNIDYNE
metal case and a shock-mounted cartridge, insensitive
to handling noise or mechanical vibration.
Models 548 and
microphones or they can be stand-mounted with the
supplied A25B slip-in swivel adapter. Model 548 is
designed for applications -where a switch is not required; Model 548SD is equipped with a magnetic reed
On-Off switch. Model
the attached swivel assembly for stand-mounting.
Model 548SD-CN: Same as Model 548SD, except
supplied with professional three-pin male audio con- fessional audio-connector on equipment end of
nector on equipment end of cable. (See Specifications cable (548SD-CN), and with On-Off switch mounted
for details on cable.)
IV is ideal for use by professional
IV has an exceptionally uniform uni-
and excludes un-
IV features an extremely rugged all
548SD can be used as hand-held
548SH has an On-Off switch on
VARIATION Available in four versions: without switch (548),
Microphone Features:
.
Unusually effective cardioid (unidirectional) pickup
pattern reduces feedback (annoying loudspeaker
"squeals") and prevents echoing (boominess) that
sometimes occurs in partially filled halls. Can also
be used closer to loudspeakers than usual without
creating feedback problems
Response especially effective for announcing, narration, vocal and instrumental music
Shock-mounted cartridge for quiet operation
Convenient selection of either high or low imped-
ance
548SD-CN)
.
Rugged professi~nal three-pin audio connector on
.
Strong, detachable cable especially selected for
effective shielding from hum pickup
.
Supplied with an .050" wrench and a 4-40 socket
setscrew (see Figure 4) to securely lock the microphone to the cable connector (548,
548SD-CN)
.
Versatile-for use in the hand or on a standindoors or outdoors
.
Rugged and dependable under all operating conditions
with magnetic reed On-Off
magnetic reed On-Off switch and three-pin pro-
on attached swivel assembly (548SH).
switch
548SD, and
(548SD), with
Copyright 1980, Shure Brothers
27A1559
(TC)
Inc.
U.S. Patents
3,132,713,
Printed in
and
3,240,883
U.S.A.
Page 2
SPECIFICATIONS
TY pe
Dynamic
Frequency Response
40 to 15,000 Hz (see Figure 1)
.:
6
$
w
ra~au~*~~
t*
%an
TYPICAL
Polar Pattern
Cardioid (unidirectional)-uniform with frequency,
symmetrical about axis (see Figure 2)
Impedance
Dual. Microphone rating impedance is 150 ohms
(240 ohms actual) for connection to microphone
inputs rated at 19 to 300 ohms and "High" for connection to high-impedance microphone inputs. Wired
for low impedance as shipped.
Output Level (at 1,000 Hz)
Open Circuit Voltage*
Power Level**
*O dB = 1 volt per microbar
**0 dB = 1 milliwatt per 10 microbars
Switch
548SD and 548SD-CN: Built-in magnetic reed OnOff switch with lockplate. To lock switch in On
position, remove screw on lockplate and turn
plate 180". Reassemble and tighten screw.
548SH: Built-in slide-to-talk, positive detent On-Off
switch mounted on attached swivel assembly; sup-
plied with accessory lockplate.
Cartridge Shock Mount
Internal rubber vibration-isolator
Swivel
548SH: Positive action, permits tilting microphone
through
135", suitable for mounting on stand with
Ti"-27 thread
Swivel Adapter
548, 548SD, and 548SD-CN: Positive action, adjustable through
easy removal for hand-held use, suitable for mounting on stand with %"-27 thread
Case
Black and satin-chrome finished all-metal case and
grille with stainless steel screen
Cable
548, 548SD, 548SH-4.6m (15 ft) two-conductor
shielded (rubber-jacketed) with a professional
pin female audio connectort on the microphone end
548SD-CN-6.lm (20 ft) two-conductor shielded
(rubber-jacketed) with a professional three-pin fe-
FREQUENCY
FIGURE
POLAR
FIGURE
RESPONSE
1
PATTERN
2
IMPEDANCE
Low
-
. . . . . -76.0 dB
High
-
-54.0 dB
(.I58 mV) (2.0 mV)
.
. . . . . . . . . .
.
-56.0 dB
90" from vertical to horizontal, permits
three-
lock-
male audio connectort on the microphone end and
a professional three-pin male audio
connectort on
the equipment end
t
Designed
A3
(Q.G.)
to
mate
series
with
or
equivalent
Cannon
XL
series,
connector.
Switchcraft
Dimensions
See Figure
3
MODELS
OVERALL
(L5f16 IN.) 41 1
MODEL
548SH
548,
548SD
AND
(1-116 IN
5fV-27
(I-Sf8 IN
3
548SD-CN
I
THD
mm
I
DIMENSIONS
DIMENSIONS
I,
-
OVERALL
FIGURE
Weight
Net
Combined
(less cable) Net Packaged
548SH 4609 7339 9449
&
548SD 31 1 g
548
548SD-CN 31 1
(16 oz)
(1 1 02)
g 7789 9759
(28% oz) (37 oz)
7239 8429
(25% 02) (33 oz)
(1 1 02) (30% oz) (38% oz)
OPERATION
Models 548, 548SD, 548SD-CN, and 548SH are dualimpedance microphones for connection to a 19 to 300
ohm rated input or to a high-impedance input. The microphones are shipped from the factory connected for
low-impedance operation.
The low-impedance connection (as shipped) is
recommended where long cable lengths are required
or under conditions of severe hum disturbance. The
permissible cable length is practically unlimited since
neither response nor level is appreciably affected by
long cables. Shure Model A95 Series Line Matching
Transformers are available for use when a
low-impedance microphone line is desirable but the associated
amplifier has a high-impedance input. These transformers provide a proper impedance match between a
19 to 300 ohm microphone line and a high-impedance
input and are available with various input and output
connectors.
IMPEDANCE SELECTION
Models 548, 548SD, and 548SD-CN are shipped connected for low-impedance operation. To change to
high impedance (see Figures 4 and 5), proceed as
follows:
1. Remove plug element at receptacle end of microphone by turning slotted setscrew in (counterclockwise) and carefully withdrawing plug element from case.
2. Disconnect 2-terminal impedance selection socket from rear of plug element.
Page 3
SLOTTED SET SCREW
r
PLUG
ELEMENT
7
EDANCE SELECTION
SOCKET
MODELS
548,
548SD
AND
IMPEDANCE
SELECTION - RECEPTACLE
FIGURE
CARTRIDGE
GROUND
TERMINAL-,
REED
SWITCH
:CASE GROUND IMPEDANCE POSITIONI
POSITIVE PRESSURE PRODUCES POSITIVE VOLTAGE ON PIN
LOW IMPEDANCE; ON PIN I. HlGH IMPEDANCE.
CARTRKXjE TRbNSFORMER PROFESSIONAL THREE-PIN CABLE
GROUND
TERMINAL-\
,BLACK
ICASE
POSITIVE PRESSURE PRODUCES POSITIVE VOLTAGE 'OCKET IN
ON PIN
TERMIN,#&
[CODED
~TI!
GROUND
2,
LOW IMPEDANCE;
TRANSFORM3 PROFESSIONAL THREE-PIN
rTERMINAL C0DED"A"
BLACK
MODELS
548SD
A
YELLOW
MODEL
INTERNAL
ON
548
CONNECTIONS
PIN I, HlGH IMPEDANCE. IMPEDANCE PoSITION)
-
INTERNAL
FIGURE
548SD-CN
END
4
AUDIO CONNECTORS
..LCE
I SOCKET (SHOWN IN LOW
AND
548SD-CN
AUDIO CONNECTORS
UAl F FFUAl
...
-
...........
'-IMPEDANCE
CONNECTIONS
5
OF
MICROPHONE
2,
F
SELECTION
CABLE
3. Reconnect 2-terminal impedance selection socket in reverse position so that pin 3 of plug element is inserted in socket terminal "H".
4.
Reassemble plug element into microphone and
seat setscrew securely by turning out (clockwise).
Model
548SH is shipped connected for low-impedance operation. To change to high impedance (see
Figure 6), proceed as follows:
1. Remove the two No. 2-56 screws holding the
switch to connector and switch housing.
Remove the nameplate and take the switch out
2.
of the switch housing.
3. Proceed as described in steps 2 and 3 above.
Re-assemble switch and nameplate to switch
4.
housing. Tighten screws securely.
CARTRIDGE TRANSFORMER SWITCH THREE-PIN PROFESSIONAL CABLE
WDlO CONNECTORS
FEMPLE
MALE
bT
SHIELD
I
I
1
i;'o"g~4$
MODEL
548SH
-
INTERNAL
FIGURE
CONNECTIONS
6
CONNECTIONS
When using the microphone in low impedance, the
BLACK and WHITE cable leads are the "hot" conductors for balanced line connections to a low-impedance
amplifier input; the shield is connected to the chassis
or amplifier ground.
When using the microphone in high impedance, the
WHITE cable lead is the "hot" conductor for connection to a high-impedance amplifier input; the shield
is connected to the chassis or amplifier ground. The
BLACK cable lead should be insulated at the equipment end when not used.
PHASING
To test two microphones and/or their cables for
proper phasing, connect them to an amplifier and
talk or sing into them while holding them three or
four inches apart. The sound from the speakers should
be the same when talking into either microphone or
directly between them if they are in phase with each
other. If the sound drops drastically, or if a dead spot
is found when talking between the two microphones,
either the microphones or their cables (low impedance
only) are out of phase. All cables and microphones
should be tested in this manner to insure that they
are in phase with each other.
To change the phase of a low-impedance microphone
cable, either use a Shure
A15PRS Phase Reverser
or interchange the wires connected to pins 2 and 3
of the connector. To change the phase of a microphone, the microphone cartridge leads must be inter-
changed (see Figures 5 and 6). This should be performed by your dealer, the Shure Factory Service
Department, or other qualified service personnel.
FURNISHED ACCESSORIES
Swivel Adapter (548, 548SD, 548SD-CN)
......
.A25B
Connector Locking Kit (548, 548SD,
548SD-CN)
Lockplate (548SH)
...........................
.....................
.90NR1371
90CK1371
OPTIONAL ACCESSORIES
Line Matching Transformer
Windscreen
...............................
.............
.A95 Series
A61WS
Quick Disconnect Adapter
(548,
548SD, 548SD-CN)
(548SH)
Desk Stand
...................................
....................
..............
.S37A, S39A, S40A
.A45, A45B
A47
REPLACEMENT PARTS
Cartridge (all models)
Cable (548,
548SH, 548SD)
(548SD-CN)
Screen and Grille Assembly (all models)
Plug Element (all models)
On-Off Switch (548SD, 548SD-CN)
(548SH)
.........................
.........................
...................
.....
.RK38G
................
..........
.RK169P
RKIO6S
....................
R48
.C59
C50CN
RK32S
ARCHITECTS' SPECIFICATIONS
The microphone shall be a moving coil (dynamic)
type with a frequency response of 40 to 15,000 Hz. The
unit shall have a cardioid polar characteristic. The
cancellation at the sides shall be approximately 6 dB,
and the cancellation at the rear shall be 15 to 20 dB.
The microphone shall be dual impedance with a rated
impedance of 150 ohms for connection to microphone
inputs rated at 19 to 300 ohms and "High" for connec-
tion to high-impedance microphone inputs. (Impedance change shall
be solderless at the microphone
connector.)
Page 4
The microphone output shall be:
Low Impedance
0 dB = 1 milliwatt per 10 microbars
High Impedance .
0 dB = 1 volt per microbar
Models 548SD, 548SD-CN, and 548SH shall be
equipped with a built-in On-Off switch.
Models 548,
with a swivel adapter, adjustable through
vertical ta horizontal, and suitable for mounting on a
stand having a
Model
justable through
a stand having a
Models 548,
with a detachable
cable with a professional three-pin audio connector*
(female) on the microphone end.
Model 548SD-CN shall be provided with a detachable
6.lm (20 ft) two-conductor shielded cable with professional three-pin audio connectors* (male and female)
on the equipment and microphone ends.
The overall dimensions of Models 548,
548SD-CN shall be 157
40 mm
(1-9116 in.) in diameter.
548SD, and 548SD-CN shall be provided
548SH shall be equipped with a swivel, ad-
.
. . .
. .
.
.
. . . . . . . . -56.0
.
. . . . . . . .
%"-27 thread.
135", and suitable for mounting on
%"-27 thread.
548SD, and 548SH shall be provided
4.6m (15 ft) two-conductor shielded
mm (6-3/16
. . . .
. . -54.0 dB
in.)
dB
90" from
548SD, and
in length and
The overall dimensions of Model
mm (4-23/32 in.) in height, 148 mm (5-27132 in.) in
depth, and 39.7 mm
The microphone shall be
548SD, 548SD-CN, 548SH, or equivalent.
*Designed to mate with Cannon
(Q.G.)
series or equivalent connector.
This Shure product is guaranteed in normal use to
be free from electrical and mechanical defects for a
period of one year from date of purchase. Please
retain proof of purchase date. This guarantee includes
all parts and
all other guarantees or warranties, express or implied,
and there shall be no recovery for any consequential
or incidental damages.
Carefully repack the unit and return it prepaid to:
If outside the United States, return the unit to your
dealer or Authorized Shure Service Center for repair.
The unit will be returned to you prepaid.
labor. This guarantee is in lieu of any and
SHIPPING INSTRUCTIONS
Shure Brothers Incorporated
Attention: Service Department
1501 West Shure Drive
Arlington Heights, Illinois 60004
(1-9/16 in.) in width.
GUARANTEE
548SH shall be 120
the Shure Model 548,
XL
series, Switchcraft
A3
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