SCALE IS 5 DECIBELS PER DIVISION
Polar Pattern
200 Hz
LEGEND
5 kHz
1 kHz
8 kHz
240
180
210
270
300
330
0
150
120
90
30
60
12" or more on axis
s
100
50
200
LEGEND
10k
5k
1k
500
2k
20k
Frequency in Hertz
Frequency Response
Response in dB
10 dB
• Designed for close-up vocal use
• Silent on-off operation thanks to MagnaLock
™
switch design
• Hi-ENERGY
®
neodymium magnet for improved output and
transient response
• Two-stage ball-type screen reduces wind noise and “popping”
during close use
• Corrosion-resistant contacts from gold-plated XLRM-type
connectors
• Rugged design and construction for reliable performance
• Cardioid polar pattern reduces pickup of sounds from the sides
and rear, improving isolation of desired sound source
Output from the microphone’s XLRM-type connector is low
impedance (Lo-Z) balanced. The signal appears across Pins 2 and 3;
Pin 1 is ground (shield). Output phase is “Pin 2 hot” – positive
acoustic pressure produces positive voltage at Pin 2.
Plug Type
Ground
Audio “+”
Audio “–”
XLR
Pin 1
Pin 2
Pin 3
1
/
4
" “TRS”
Sleeve
Tip
Ring
1
/
4
" Sleeve
Tip
Sleeve
To avoid phase cancellation and poor sound, all mic cables must be
wired consistently: Pin 1-to-Pin 1, etc. For a high-impedance (Hi-Z)
mic input, connect a Lo-Z balanced cable to a Hi-Z matching
transformer (A-T CP8201 or equal) at the equipment input.
When using the PRO 31 in settings with a stage monitor speaker,
the speaker should be located 180° off axis (at the rear of the
microphone). This placement, in conjunction with the microphone’s
uniform cardioid pickup pattern, will virtually eliminate the possibility
of undesired audio feedback.
The PRO 31 utilizes a MagnaLock on/off switch. This specially
designed switch operates silently and may be locked in the “on”
position to prevent accidental turn-off during use. To lock, slide the
switch up into the “on” position (Fig. 1a). Using a small flat-head
screwdriver, rotate the small screw in the center of the switch 90
degrees (
1
/
4
turn) counter-clockwise (Fig. 1b). Never force the screw.
When the screw slot position is horizontal (“across” the microphone
body), the switch is locked. To unlock the switch, turn the screw 90
degrees clockwise until the screw slot position is again vertical (in
line with the microphone body). Never try to turn the switch more
than 90 degrees or
1
/
4
rotation. The switch may only be locked in the
“on” position. Do not try to turn the screw when the switch is in the
“off ” position.
Take care to keep foreign particles from entering the windscreen. An
accumulation of iron or steel filings on the diaphragm, and/or
foreign material in the windscreen’s mesh surface, can degrade
performance.
PRO 31 SPECIFICATIONS
†
ELEMENT
Dynamic
POLAR PATTERN
Cardioid
FREQUENCY RESPONSE
60-13,000 Hz
OPEN CIRCUIT SENSITIVITY
–55 dB (1.7 mV) re 1V at 1 Pa*
IMPEDANCE
600 ohms
SWITCH
MagnaLock
™
on/off
WEIGHT
(less cable and accessories)
11.0 oz (312 g)
DIMENSIONS
7.28" (185.0 mm) long,
2.09" (53.1 mm) head diameter
OUTPUT CONNECTOR
Integral 3-pin XLRM-type
CABLE
15.0' (4.5 m) cable with XLRF-type
connector at microphone end,
XLRM-type connector at equipment
end
ACCESSORIES FURNISHED
AT8470 Quiet-Flex
™
stand clamp for
5
/
8
"-27 threaded stands;
5
/
8
"-27 to
3
/
8
"-16 threaded adapter;
soft protective pouch
†In the interest of standards development, A.T.U.S. offers full details on its test
methods to other industry professionals on request.
*1 Pascal = 10 dynes /cm
2
= 10 microbars = 94 dB SPL
Specifications are subject to change without notice.
Audio-Technica U.S., Inc.,
1221 Commerce Drive, Stow, Ohio 44224
Audio-Technica Limited,
Old Lane, Leeds LS11 8AG England
www.audio-technica.com
P3893-00180 P51677-EN ©2004 Audio-Technica U.S., Inc. Printed in Taiwan
PRO 31
CARDIOID DYNAMIC MICROPHONE
O N
O N
O N
OFF
Fig. 1a
Fig. 1b
Fig.1c
Fig. 1d
Do
not
try
Do
not
turn
to lock switch
Unlocked
Locked
screw clockwise
in the “off ”
Position
Position
to lock
position
