T
PRESSURE
ZONE
MICROPHONE
®
he PZM11 LL WR is a weather-
resistant Pressure Zone Microphone
®
with a balanced, line-level output. A
plastic
membrane
inside
the
microphone protects the mic capsule
from water damage. The mic mounts in a
standard electrical outlet box. Applications
include
fast-food
restaurants,
outdoor
intercoms, toll booths, bridges, theme park
security, home automation, and so on.
The microphone can be plugged directly into a
VCR line input - no costly mic preamp is
needed. Output (via screw terminals) can be
balanced or unbalanced. Powering is by 12-24V
ACor DC. The unit can be factory-set for phan-
tom powering by special order.
In the PZM11 LL WR, frequencies below the voice
range are rolled off to reduce traffic rumble. The
high-frequency response is boosted to help
articulation. Because of its tailored response and
PZM construction, the PZM11 LL WR will pick up
conversations or other desired sounds with extra
clarity.
The unit is
“weather resistant,” which means:
• The microphone will work during and after
rainfall.
• The mic’s frequency response will change
temporarily if the membrane gets wet, but will
return to normal when dry.
• If water freezes on the membrane, the mic’s
frequency response will change, but will
return to normal when the ice melts and the
membrane dries.
• High-pressure water sprays directly on the
membrane (through the louvered wall plate)
may damage the membrane.
• The microphone is not designed to be sub-
merged.
Installation
1. Please refer to Figure 3 and locate all the parts
shown. The electrical outlet box and cables are
not included.
2. Run a 2-conductor shielded cable to the
surface where you intend to install the micro-
phone. Install a standard electrical outlet box
there (2-inch minimum depth).
3. The PZM11 LL WR can be powered by 12-24V
ACor DC.
From your power source, run a twisted pair
power cable to the mic location. Run the power
cable through the hole in the electrical box.
Service the end of the power cable.
Specifications
Transducer type:
Electret condenser.
Frequency response (typical):
80 Hz to 10,000 Hz
(see Fig. 1).
Polar pattern:
Hemispherical.
Impedance:
75 ohms, balanced. Recommended
minimum load impedance 1000 ohms.
Open-circuit sensitivity, typical:
1.4 V/Pa.
Power sensitivity, typical:
+8 dBm/Pa.
Equivalent noise level (self-noise):
26 dB SPL typical
(0 dB = .0002 dyne/cm
2
), A-weighted.
S/N Ratio:
68 dB at 94 dB SPL.
Maximum SPL:
100 dB SPL produces 3% THD at
maximum gain.
Operating voltage:
12-24V ACor DC, Phantom
powering by special order.
Polarity:
Positive pressure on diaphragm produces
positive voltage on audio+ terminal with respect to
audio
– terminal
Current drain:
4 milliamperes.
Operating temperature range:
–10 to +60 deg. C, 14
to 140 deg. F. The mic still works at
–40 deg. Cbut
its sensitivity is reduced. When the mic is returned
to normal operating temperature, its sensitivity will
be /
–3 dB of normal.
Output connector:
Screw terminals labeled AUDIO+,
AUDIO
– and GROUND.
Cable:
None supplied. Use 2-conductor shielded mic
cable and twisted-pair power cable.
Materials:
Steel plate and high-impact plastic capsule
holder. Plastic membrane, part no. 127255-1.
Finish:
Silver. If you paint the mic, take care not to
paint inside the louvered wall plate.
Net weight:
2.5 oz. (71 g).
Dimensions:
4.530 x 2.780 x 1.722 inches (LWD)
(see Fig. 2).
* 1 pascal = 10 dynes/cm
2
= 10 microbars = 94 dB SPL.
Fig. 1
Fig. 2
Frequency Response
Frequency in Hz
PZM11 LL WR
