Crown PZM-20R User manual

POLAR
PATTERN
PZM-20R
PZM-20RW
Fig. 2A
®
The Crown®PZM-20R is a Pressure
Zone Microphone®designed for per
manent flush-mounting in tables,
lecterns, pulpits, and judicial benches. Its
unobtrusive appearance and hemispherical
pickup pattern make it ideal for conference
table use. The microphone fits into a 4.59-in.
(11.659-cm) square hole or in a standard
4.0-in. x 4.0-in. (10.16-cm x 10.16-cm) elec-
trical outlet box.
Electronics in the base of the 20R adapt the
microphone for phantom powering. No ex-
ternal power-supply interface is required. The
microphone plugs directly into a phantom
power supply providing 12 to 48 volts.
The wide-range frequency response of the
20R is emphasized at high frequencies for
clarity and articulation. Low frequencies be-
low the voice range are filtered out to reduce
rumble.
Three small guard-posts prevent papers from
sliding underneath the cantilever arm and
altering the frequency response.
Like other Pressure Zone Microphones,
the 20R utilizes the Pressure Recording
Process™ in which a miniature condenser
microphone capsule is arranged very close
to a sound-reflecting plate or boundary, The
capsule is mounted in the “Pressure Zone”
just above the boundary, a region where
sound coming directly from the sound source
combines in-phase with sound reflected
off the boundary. The benefits are a wide,
smooth frequency response free of phase
interference, excellent clarity and “reach,” a
hemispherical polar pattern, and uncolored
off-axis response.
Suggestions For Use
The PZM-20R differs from other PZMs in that
it is a stationary microphone, generally not
moved from one location to another. Before
installing it, first check that the pickup will
be adequate by testing a regular PZM placed
where you plan to install the 20R.
Avoid areas where items might be placed on
top of the microphone. Once you’ve decided
on the microphone position, rout a recessed
hole according to the dimensions in Fig. 2B
on the reverse side.
Specifications
Type: Pressure Zone Microphone.
Element: Electret condenser.
Frequency response (typical): 80 Hz to 20 kHz (see
Fig. 1).
Polar pattern: Hemispherical on an infinite plane.
Open circuit sensitivity: 7 mV/Pa* (–43 dB re 1
volt/Pa).
Power sensitivity: –43 dB re 1 mW/Pa. EIA sensitiv-
ity –135 dBm.
Impedance: 240 ohms balanced. Recommended
minimum load impedance 1000 ohms.
Equivalent noise level: 20 dB SPL (0 dB = 0.0002
dyne/cm2), A-weighted.
S/N ratio: 74 dB at 94 dB SPL.
Maximum SPL: 150 dB SPL at the microphone pro-
duces 3% THD.
Polarity: Positive pressure on the diaphragm pro-
duces positive voltage on terminal 2 with respect to
terminal 3 of the output terminal strip.
Operating voltage: Phantom power, 12 to 48 volts
DC, positive voltage on terminals 2 and 3 with re-
spect to terminal 1 of the output terminal strip.
Current drain: 1.1 mA.
Color: Black.
Connector: Screw terminals. #1 shield, #2 audio in-
polarity, #3 audio return.
Cable: None supplied; use 2-conductor shielded mi-
crophone cable.
Weight: 8.1 ounces (230 grams).
Dimensions: See Figs. 2A and 2B.
Optional accessories: Crown PH-1A phantom power
supply (single channel, battery or AC adapter
powered).
*1 pascal = 10 dynes/cm2= 10 microbars = 94 dB SPL.
Fig. 1
–20
–25
–30
–35
20 100 1K
+15
+10
+5
dB 0
–5
–10
–15
10K
Frequency Response
Frequency in Hz
Low frequency response depends on size of surface.
4.58 in.
11.63 cm
3.42 in.
8.69 cm
.187 in.
.475 cm
.250 in.
.635 cm
1.1 in.
2.695 cm
4.58 in.
11.63 cm
3.42 in.
8.69 cm
Features
• For permanent flush-mounting in tables
• Hemispherical polar pattern picks up every-
one around the microphone
• Frequency response tailored for speech
clarity
• Low-frequency rolloff reduces air-handling
noise
• Screw terminals provide low-cost connec-
tions
PRESSURE
ZONE
MICROPHONE

Crown International, Inc.
1718 W. Mishawaka Rd.
Elkhart, IN 46517-9439
TEL: [phone]
FAX: [phone]FAX
www.crownaudio.com
©2005 Crown Audio®, Inc. Specifications subject to change
without prior notice. Latest information available at
www.crownaudio.com. Crown, Crown Audio, PZM and Pres-
sure Zone Microphone are registered trademarks of Crown
International. Pressure Recording Process is a trademark of
E. M. Long Associates.
9/05 102362-5
PZM-20R
PZM-20RW
Fig. 2B
For small conference tables seating up to
eight people, mount the 20R in the center of
the table. For larger tables, use one 20R in
the middle of every four to six people. Ideally
no person should be more than 3 feet from
the nearest microphone. For maximum clarity
hold the conference in an acoustically “dead”
room with carpeting, acoustic-tile ceiling and
drapes.
Operating Instructions
Using two-conductor shielded microphone
cable, connect the output of the 20R to a
mixer microphone input that provides 12-48
volts phantom powering. This cable may be
of any length because the microphone output
is balanced low impedance.
The 20R has three screw terminals. Connect
screw #1 to the cable shield, #2 to the audio
in-polarity (hot) lead, and #3 to the audio
cold lead. On the equipment end of the cable,
solder the cable to the XLR-type connector as
follows: pin 1: shield, pin 2: audio in-polarity
(hot) lead, pin 3: audio cold lead.
If your mixer or recorder does not provide
phantom powering, you’ll need a microphone
power supply. Crown offers a model PH-4B
power supply for powering up to four PZMs.
Also available is a single channel AC/bat-
tery supply, Crown model PH-1A. Connect
the 20R output to the power-supply input;
connect the power-supply output to your
recorder or mixer mix input.
Architects’ and Engineers’ Specifications
The microphone shall be the Crown Model
PZM-20R or equivalent. The microphone
shall be a Pressure Zone, electret condenser
type, designed for permanent flush-mount-
ing in a 4.59-in. (11.659-cm) square hole or
in a standard 4.0-in. x 4.0-in. (10.16-cm x
10.16-cm) electrical outlet box. A smooth
frequency response from 80 Hz to 20,000 Hz
shall be obtained. The microphone shall have
a sensitivity of –43 dBV/Pa (measured on
an infinite boundary). The microphone shall
accept a 150 dB SPL input while producing
no more than 3% THD (open-circuit termina-
tion). Equivalent noise shall be typically 20
dBA (0 dB = .0002 dyne/cm2). The Crown
model PZM-20R is specified.
Warranty
Crown professional microphones are guaran-
teed against malfunction for a period of three
years from date of original purchase. Please
refer to the enclosed full warranty sheet for
more detail.
Service
If the microphone does not function properly,
replace or repair mic cables and connectors,
check the power supply. If it is determined
that the microphone needs service and you
want 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
West Mishawaka Road, Elkhart, Indiana
46517-9439. For further assistance or techni-
cal support call 800-342-6939.
++
+
+
A
(4) PILOT HOLES FOR ROUTER
0.25 in. (0.635 cm) RADIUS
(USE 0.5 in. (1.27 cm) ROUTER BIT)
A
4.094 in.
10.399 cm
4.59 in. (11.659 cm) SQUARE
0.188 in. (0.476 cm) ROUTER DEPTH
2.75 in. (6.985 cm)
SQUARE
TABLE
TOP
4.094 in.
10.399 cm